RELATED APPLICATIONS

[0001 ] This application claims priority to and claims the benefit of U.S. Application Serial No. 62/245.194 fi led on October 22, 2015, which is hereby incorporated by reference in its entirety.

[0002] This application is related to and claims priority from co-pending U.S. Patent Application No. 14/485,478 filed on 9/ 1 2/2014 entitled ^" Centralizer and Locking Collar' by Napoleon Arizmendi, which claims priority to provisi onal patent application No. 61 /877,91 3, filed on 9/ 1 3/2013 and is assigned to the assignee of the present invention.

[0003] This application is also related to and claims priority from co-pending U.S. Patent Application No. 14/485,464 filed on 9/12/201 4 entitled "Locking Centralizer by Napoleon Arizmendi, which claims priority to provisional patent application No. 61 /877,909, filed on 9/13/2013 and is assigned to the assignee of the present invention.

[0004] This application is also related to and claims priority from co-pending U.S. Patent Application No. 14/485,448 filed on 9/12/201 4 entitled "Locking Collar" by Napoleon Arizmendi which claims priority to provisional patent application No. 61 /877,904. filed on 9/13/2 13 and is assigned to the assignee of the present invention.

TECHNICAL FIELD

[0005] Embodiments described are related to a wellbore pipe, or casing, centralizer that is self-locking onto a wellbore pipe.

CENTER-005 BACKGROUND

[0006] Within the area of subterranean well construction, centralizers are often used to keep the casing centered in the wellbore to faci litate placement of the casing in the bore and to prevent cementing the pipe against a side of the borehole. Centralizers isolate the outer surface of the wellbore pipe from the inner surface of the wellbore. Additionally, in long horizontal sections of wellbore. centralizers provide support of the tubular casing section, preventing the w ellbore pipe from laying on the lower inner surface of the horizontal wel I bore.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate various embodiments and, together with the Description of

Embodiments, serve to explain principles discussed below. The drawings referred to in this brief descri ption of the drawings should not be understood as being drawn to scale unless specifically noted.

[0008] FIG. 1 is an isometric vie of an embodiment of a lock collar illustrated in accordance with principles of the present invention descri bed herein.

[0009] FIG. 2 is an isometric view of a spring member for use with the lock collar of FIG. 1.

[0010] FIG. 3 is an isometric view of the lock collar illustrated with the spring member of FIG. 2 in place

CENTER-005 [0011] FIG. 4 is an isometric sectioned view of the lock collar illustrated with the spring member of FIG. 2 in place.

[0012] FIG. 5 is an isometric vie of a second embodiment of a lock collar illustrated in accordance with principles of the present invention descri bed herein.

[0013] FIG. 6 is an isometric view of a spring member for use with the lock collar of FIG.

5.

[0014] FIG. 7 is a cross-sectional view of the lock collar of FIG. 5.

[0015] FIG. 8 is a cross-sectional view of the lock collar of FIG. 5. showing the function of the wedge surface in response to axial force against the lock collar.

[0016J FIG. 9 is an isometric view of an embodiment of a centralizer body illustrated in accordance with principles of the present invention descri bed herein.

[0017] FIG. 10 is an isometric view of a spring member for use w ith the centralizer body of FIG. 9.

[0018] FIG. 1 1 is an isometric view of the centralizer i l lustrated with the spring member of FIG. 10 in place.

[0019] FIG. 12 is an isometric cross-sectional view of the centralizer illustrated with the spring member of FIG. 10 in place.

CENTER-005 [0020] FIG. 13 is a cross-sectional side view of the centralizer 1 10 that defines a section E-E through which both end positions of the spring may be seen.

[0021 ] FIG. 14 is an axial cross-section of the centralizer, illustrated as mounted on a tubular, and illustrated inside a well bore, i llustrated at a section line that permits viewing of both ends of the spring member, with the spring in the installed, uncompressed state.

[0022] FIG. 15 is an axial cross-section of the centralizer, illustrated as mounted on a tubular, illustrated at a section line that permits viewing of both ends of the spring member, shown with the central izer rotated counterclockwise and loading the spring against the internal wedge surface.

|0023] FIG. 1 is an isometric view of a second embodiment of a centralizer body illustrated in accordance with principles of the present invention described herein.

[0024] FIG. 17 is an isometric view of a spring member for use with the centralizer of FIG. 16.

[0025] FIG. 18 is an isometric vi ew of the centralizer illustrated with the spring member of FIG. 1 7 in place.

[0026] FIG. 19 is an isometric cross-sectional view of the centralizer illustrated with the spring of FIG. 17 in place.

CENTER-005 [0027] FIG. 20 is a cross-sectional side view of the centralizer of FIGS. 16- 19.

[0028] FIG. 21 is an isometric view of an embodiment of a centralizer body illustrated in accordance with principles of the present invention described herein.

[0029] FIG. 22 is an isometric view of a spring member for use with the centralizer body of FIG. 21 .

|0030] FIG. 23 is an isometric view of the centralizer illustrated with the spring member of FIG. 22 in place.

[0031 ] FIG. 24 is an isometric cross-sectional view of the centralizer illustrated with the spring member of FIG. 22 in place.

|0032] FIG. 25 is a cross-sectional side view of the centralizer that defines a section E-E through which both end positions of the spring may be seen.

[0033] FIG. 26 is an axial cross-section of the centralizer. illustrated as mounted on a tubular, and illustrated inside a well bore, illustrated at a section line that permits viewing of both ends of the spring member, with the spring in the installed, uncompressed state.

[0034] FIG. 27 is an axial cross-section of the centralizer, illustrated as mounted on a tubular, illustrated at a section line that permits viewing of both ends of the spring member, show n with the centralizer rotated counterclockwise and loading the spring against the internal wedge surface.

CENTER-005 [0035] FIG. 28 is an isometric view of a second embodiment of a centralizer body illustrated in accordance with principles of the present invention described herein.

[0036] FIG. 29 is an isometric view of a spring member for use with the centralizer of FIG. 28.

[0037] FIG. 30 is an isometric view of the centralizer illustrated with the spring member of FIG. 29 in place.

|0038] FIG. 31 is an isometric cross-sectional view ⁷ of the centralizer illustrated with the spring of FIG. 29 in place.

|0039] FIG. 32 is a cross-sectional side view of the centralizer of FIGS. 28-3 1 .

[0040] FIG. 33 is an isometric view of a third embodi ment, being for a lock col lar.

[0041] FIG. 34 is an isometric view for the centralizer.

[0042] FIG. 35 is an end view of the lock collar mounted on the centralizer.

[0043) FIG. 36 an isometric view of the lock collar mounted on the centralizer.

[0044] FIG. 37 is an illustration of an exemplary centralizer in accordance with an embodiment.

CENTER-005 [0045] FIG. 38 is a sectional view of and exemplar)' centralizer showing a first locking mechanism and a second locking mechanism in a retracted position, in accordance with an embodiment.

[0046J FIG. 39 is a sectional view of and exemplaiy centralizer having a retaining member maintaining a first locking mechanism and a second locking mechanism in a retracted position, in accordance with an embodiment.

[0047] FIG. 40A shows an initial disabled state of an exemplaiy centralizer in accordance with an embodiment.

[0048] FIG. 40B shows an intei median state of an exemplaiy centralizer in accordance with an embodiment.

[0049] FIG. 40C shows a locked or enabled state of an exemplaiy centralizer in accordance with an embodiment.

[0050] FIG. 41 shows a sectional view of an exemplaiy centralizer having a gripping edge that is helically disposed about a circumference of the slip spring in accordance with an embodiment.

[0051 ] FIG. 42 is a flow diagram of an exemplaiy method for attaching a centralizer to a tubular in accordance with an embodiment.

CENTER-005 [0052] FIG. 43 is a flow diagram of an exemplary method for using a wellbore pipe centralizer in accordance with an embodiment.

[0052a] FIG. 44 is a perspective view of a twisted square wire.

DETAILED DESCRIPTION

[0053] Reference will now be made in detail to embodiments of the subject matter, examples of which are illustrated in the accompanying drawings. Wh i le the subject matter discussed herein will be described in conjunction with various embodiments, it wi ll be understood that they are not intended to limit the subject matter to these embodiments. On the contrary, the presented embodiments are intended to cover alternatives, modifications and equ ivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the Detailed Description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present subject matter. However, embodiments may be practiced without these specific details. In other instances, well known methods, procedures, and components have not been described in detai l as not to unnecessarily obscure aspects of the described embodiments.

Notation and Nomenclature

[0054] Any use of "top," "bottom," "above," "below," other directional terms, and variations of these terms is made for convenience, but does not require any particular orientation of the components. The terms "helical" and "spiral" are not i ntended to require perfectly mathematical helix or spirals, and are also particularly intended to include square ended, closed ended, and ground versions of springs of these types, various screw thread forms, and also as the channels that would receive any of these shapes.

CE NTER-005 [0055] Embodiments described herein relate to a centralizer that can be used to center a wellbore pipe, such as for example a well casing or tubing, within a wellbore. In one embodiment, the centralizer described herein attaches to an outside surface of a pipe section without requiring conventional attachment procedures such as instal ling locking pins, lightening a retaining device or any other conventional installation practice that requires an externally applied force, such as for example pounding with a hammer, to lock a centralizer to a pipe section. These conventional installation practices usually rely on using an applied force to either tighten a retaining device such as in driving securing pins. Embodiments described herein do not require an extemally applied force to secure the centralizer to a pipe segment, as with conventional centralizers.

[0056] Embodiments described herein include a centralizer that comprises a first self locking mechanism including a spring that is able to passively, such as with only the tension in the spring, grip onto a pipe section once positioned. The spring mechanism in one embodiment restricts axial movement of the central izer with respect to a pi pe section. In one embodiment, the centralizer further comprises a second sel f locking mechanism that augments the gripping of first self locking mechanism to also restrict movement of the centralizer with respect to a pipe section.

[0057] In one embodiment, the second self locking mechanism restricts rotational movement of the centralizer with respect to the pipe section. In one example, the second self locking mechanism includes one or more twisted square wires having ridges or sharp wickers in a helix formation about the wire that provide a gripping and / or frictional force between

CENTER-005 the centralizer and the pipe section that resists a rotational movement of the centralizer. See for Example Twisted Square Wire 4400 in FIG. 44.

[0058] FIG. 1 is an isometric view of a first embodiment of a lock collar 10 illustrated in accordance with principles of the present invention described herein. Referring to FIG. 1. lock collar 1 has a cyl indrical body 12 with a hollow interior. Lock collar 10 has an interior surface 14 and an exterior surface 1 6. Interior surface 14 may be wedge shaped, having a circumferential peak 1 5 A fi rst interior channel 1 8 is located on interior surface 14. A second interior channel2() is located on interior surface 14. A first aperture 22 extends between exterior surface 1 and first channel I S. A second aperture 24 extends between exterior surface 1 and second channel 20.

[0059] FIG 2 is an isometric vie of a typical first and second expandable spring member 30 and 40. respecti vely, having a pair of opposing ends 32 (42) and 34 (44).

[0060| FIG. 3 is an isometric vie of lock col lar 1 i llustrated with first spring member 30 located in first channel 1 8. Opposing ends 32 and 34 of first spring 30 are positioned adjacent to aperture 22 Second expandable spring member 40 is located in second channel 20.

Opposing ends 42 and 44 of second spring 40 are positioned adjacent to aperture 24.

[0061 ] A first retaining pin 50 is removably located in first aperture 22, between ends 32 and 34 of first spring 30 so as to hold first spring 30 in an expanded position. A second retaining pin 52 is removably located in second aperture 24 between ends 42 and 44 of second spring 40 so as to hold second spring 40 in an expanded position.

CENTER-005 [0062] With first and second springs 30 and 40 held in the expanded position by their respective retaining pins 50 and 52, lock collar 10 may be placed over the exterior surface of the down hole well tubular to which it will lock. This is possible because the interior diameter of first and second springs 3 0 and 40 in the expanded state is equal to or greater than the exterior diameter of the tubular.

[0063] As illustrated, first and second retaining pins 50 and 52 are removable from exterior surface 16 side of lock collar 10. The interior diameter of first and second springs 30 and 40 in an unexpanded state is less than the exterior diameter of the tubular over whi ch lock collar 10 will be located. In this manner, removal of retaining pins 50 and 52 wil l release spring members 30 and 40 such that they will grip the exterior surface of the do nhole well tubular.

|0064] FIG. 4 is an isometric sectioned view of lock collar 1 0 illustrated with spring members 30 and 40 held in channels 1 8 and 20 by retainers 50 and 52. Circumferential peak 1 5 creates a wedge shape to which a wedge surface 26 urges spring 30 outwardly. Similarly, circumferential peak 15 creates a wedge shape to which a wedge surface 28 urges spring 40 outwardly. Wedges 26 and 28 discourage axial movement of springs 30 and 40 in relationship to circumferential peak 15, thus strengthening the gripping force of lock col lar 1 on the tubular to which it is attached.

|0065] In another embodiment, springs 30 and 40 may have a knurled or profi led surface to assist in gripping the pipe OD.

|0066] FIG. 5 is an isometric view of a second embodiment of a lock col l ar i l lustrated in CENTER-005 accordance with principles of the present invention described herein. As illustrated in FIG. 5, lock collar 100 has a cylindrical body 102 with a hollow interior. Lock collar 100 has an exterior surface 104 and an interior surface 106. Interior surface 1 6 may be wedge shaped, having a circumferential peak 1 8. Peak 108 forms opposing wedge surfaces 1 10 and 1 12. A generally helical interior channel 1 14 is located on interior surface 1 6.

[0067] A first aperture 122 (not visible) extends between exterior surface 104 and helical channel 114. A first retaining pin 150 is removably located in first aperture 122. A second aperture 124 (not visi ble) extends between exten or surface 1 04 and channel 1 14. A second retaining pin 152 is removably located in second aperture 124.

[0068] FIG 6 is an isometric view of an expandable helical spring member 130, having a first end 132 and an opposite second end 134. Spring 1 30 is ill ustrated in an embodiment in which it has open ends, and is not ground. Referring back to FIG. 5. spring member 1 30 is located in channel 1 14. between retaining pins 150 and 1 52.

[0069] FIG. 7 is a cross-sectional view of lock collar 1 0 illustrated with spring member 130 located in cham l el l 14. End 132 of spring 130 is in engagen l ent with retaining pin 150. End 1 34 of spring 1 30 is in engagement with retaining pin 152. Spring 1 30 engages interior wedges 1 1 and 1 12. The open end. or not ground design, of spring 1 30 requires less axial force for lock collar 1 00 to grip the pipe OD due to the "point load" contact between the end of the last coil and wedge 1 10 and 1 12 surfaces.

[0070] With spring 130 held in the expanded position by retaining pins 150 and 152. lock collar 100 may be placed over the exterior surface of the downhole w ell tubular to which it CENTER-005 will lock. This is possible because the interior diameter of spring 130 in the expanded state is equal to or greater than the exterior diameter of the tubular.

[0071 ] First and second retaining pins 150 and 152 are removable from exterior surface 104 side of lock col lar 100. The interior diameter of spring 130 in an unexpanded state is less than the exterior diameter of the tubular over which lock collar 1 0 will be located. In this manner, removal of retaining pins 1 50 and 152 will release spring member 130 such that it will grip the exterior surface of the downhole well tubular.

[0072] FIG. 8 is a cross-sectional M ew of lock collar 100 illustrated with spring member 1 30 located in channel 1 14. Circumferential peak 108 separates interior wedges 1 10 and 1 12. Wedges 1 10 and 1 12 discourage axi al movement of spring 130 in relationship to circumferential peak 1 8. thus strengthening the gripping force of lock collar 100 on the tubular to w hich it is attached. In another embodiment, spring 130 may have a knurled or profi led surface to assist in gripping the pipe OD. As shown in FIG. 8, lock collar 100 I nay become slightly offset from the pipe diameter as the load is increased; the "point contact" will become a "l ine contact" betw een the last coil and the wedge surfaces 1 10 and 1 1 2. See Gap 'A' and Gap 'B' of FIG. 8.

[0073] FIG. 9 is an isometric view of a first embodiment of a centralizer 2010 i llustrated in accordance with principles of the present invention described herein. Referring to FIG. 9. centralizer 2010 has a cyl indrical body 2012. comprising an exterior surface 2014 and stabilizing fins 2016 extending outwards from exterior surface 2014. Body 2012 has a hollow interior with an interior surface 201 , a first edge 2020, and a second edge 2022 formed between exterior surface 2014 and interior surface 201 8.

CENTER-005 [0074] A first ramp 2024 is formed on interior surface 2018, proximate to first edge 2020, and a second ramp 2026 (see FIG. 1 1 ) is formed on interior surface 201 8, proximate to second edge 2022. A general ly helical interior channel 2030 is provided on interior surface 201 8, extending between first ramp 2024 and second ramp 2026. A fi rst aperture 2032 extends between exterior surface 2014 and first ramp 2024. A second aperture 2034 (see FIG. 1 1. aperture 2034 shown receiving retaining pin 2052) extends between exterior surface 2014 and second ramp 2026.

[0075] FIG. 10 is an isometric vie of a spring member 2040 for use w i th centralizer 2010.

Expandable spring member 2040 is provided with a first tab 2042 at one end and a second tab 2044 at its opposite end.

[0076) FIG. 1 1 is an isometric view of centralizer 201 , illustrated with spring member 2040 in place. As seen in this view, spring 2040 is located in channel 2030. A fi rst retaining pin 2050 is removably located in first aperture 2032 such that retaining pin 2050 is in engagement with first tab 2042. A second retaining pin 2052 is removably located in second aperture 2034 for engagement with second tab 2044 such that retaining pin 2052 is in engagement with second tab 2044.

|0077| FIG. 12 is an isometric cross-sectional view of centralizer 201 . In this view, the intersection of channel 2030 with first ramp 2024 and second ramp 2026 is readily visi ble. It is also seen that spring 2040 is compressed between retaining pins 2050 and 2052.

CENTER-005 [0078] FIG. 13 is a cross-sectional side view of centralizer 2010 that defines a section E-E through which both end positions of the spring may be seen.

[0079j FIG. 14 is an axial cross-section of centralizer 2010, i llustrated as mounted on tubular 20100, illustrated at a section line that permits viewing both tabs 2042 and 2044 of spring member 2040 in relationship to slopes 2024 and 2026, respectively. In this embodiment, an exemplars' angle of 2046 degrees is provided between first tab 2042 and second tab 2044. As seen in FIG. 14, rotalion in either direction will have the result of further securing centralizer 201 0 against tubular 201 00.

[0080] FIG. 15 is another axial cross-section of centralizer 201 , illustrated as mounted on tubular 20100, illustrated at section line E-E, shown with tubular 20100 rotated clockwise (centralizer 2010 rotated relatively counterclockwise) and loading spring tab 2042 against ramp 2024 to limit additional relative rotation between tubular 20100 and centralizer 2010.

[0081 ] FIG. 16 is an isometric vi ew of a second embodiment of a centralizer body 201 10 ill ustrated in accordance with principles of the present invention described herein. Referring to FIG. 16, centralizer 201 1 0 has a cylindrical body 201 12, comprising an e.xterior surface 201 14 and stabilizing fins 201 16 extending outwards from exterior surface 201 14. Body 201 12 has a hollow interior with an interior surface 201 18. a fi rst edge 201 20, and a second edge 20122 formed between exterior surface 201 14 and interior surface 201 1 8.

[0082] A first ramp 20124 is formed on interior surface 201 18, proximate to first edge 201 20, and a second ramp 201 26 is formed on interior surface 201 1 8. proximate to second edge 201 22. A first ramp 20124 is formed on interior surface 201 1 8, proximate to first edge CENTER-005 20120. A second ramp 20126 is formed on interior surface 20118, proximate to second edge 20126.

[0083] At the position where first ramp 20124 engages side 20] 20, a first slot 20170 is formed. A second slot 201 72 is formed where second ramp 20126 engages side 20122.

[0084) A third ramp 20128 is centrally formed on interior surface 201 18. A first interior circumferential wedge 20134 is formed on interior surface 201 18 and extends between first ramp 20124 and third ramp 201 28. A second interior circumferential wedge 201 36 is formed on interior surface 201 1 8 and extends between second ramp 20126 and third ramp 201 28. An aperture extends betw een exterior surface 201 1 2 and third ramp 201 28.

[0085] FIG. 17 is an isometric view of a spring member 20140 for use with centralizer 201 10 of FI G. 16. Expandable spring member 20140 has a first helical section 20142 and a second helical section 20144 connecled by a bridge portion 20146. A first tab 20148 extends outward from fi rst hel ical section 20142. A second tab 20150 extends outward from second helical section 2 144.

[0086] FIG. 1 is an isometric vi ew of centralizer 201 1 illustrated with spring member 20140 of FIG. 17 in place. FIG. 1 is an isometric cross-sectional view of centralizer 201 10 as illustrated in FIG. 1 .

[0087] Referring to FIGS. 18 and 19. it is seen that first helical section 20142 is located on first wedge 201 34. Second helical section 20144 is located on second wedge 20136. A retaining pin 201 60 is removably located in aperture 20136 for engagement with bridge CENTER-005 20146 of spring 20140. As will be seen in FIGS. 17 and 18, slots 20170 and 20172 provide a rotational limit for spring 20140 when pre-tensioning spring member 20140 against retaining pin 20160.

|0088] FIG. 20 is a cross-sectional side view of centralizer 201 1 0. In summary of the operation, when retainer pin 20160 is removed, spring 20140 is preloaded against the surface of tubular 20100, holding it in place. This prevents axial movement of centralizer 201 10 relative to tubular 20100. Clockwise rotation of tubular 20100 relative to centralizer 201 10 engages tab 2 148 between first ramp 20124 and tubular 201 0 to limit further rotation. Counterclockwise rotation of tubular 20100 relative to centralizer 201 10 engages tab 20150 between second ramp 20126 and tubular 20100 to limit further rotation. The surface of spring 20140 may be knurled or profiled to increase resistance to sliding relative to tubular 20100.

[0089) FIG. 21 is an isometric view of a first embodiment of a centrali zer 3010 i llustrated in accordance with principles of the present invention described herein. Referring to FIG. 21 . centrali zer 3010 has a cylindrical body 301 2, comprising an exterior surface 3014 and stabilizing fins 3016 extending outwards from exterior surface 3014. Body 301 2 has a hollow interior with an interior surface 3018, a first edge 3020, and a second edge 3022 formed between exterior surface 3014 and interior surface 301 8.

[0090] A first ramp 3024 is formed on interior surface 3018, proximate to first edge 3020. and a second ramp 3026 (see FIG. 23) is formed on interior surface 301 8, proximate to second edge 3022. A generally helical interior channel 3030 is provided on interior surface 301 . extending between first ramp 3024 and second ramp 3026. A fi rst aperture 3032 extends between exterior surface 3014 and first ramp 3024. A second aperture 3034 (see FIG. CENTER-005 23, aperture 3034 shown receiving retaining pin 3052) extends between exterior surface 3014 and second ramp 3026.

[0091 ] FIG. 22 is an isometric view of a spring member 3040 for use with centralizer 3010. Expandable spring member 3040 is provided w ith a first tab 3042 at one end and a second tab 3044 at its opposite end.

[0092] FIG. 23 is an isometric view of centralizer 3010. illustrated with spring member 3040 in place. As seen in this view, spring 3040 is located in channel 3030. A first retaining pin 3050 is removably located in first aperture 3032 such that retaining pin 3050 is in engagement with fi rst tab 3042. A second retaining pin 3052 is removably located in second aperture 3034 for engagement with second tab 3044 such that retaining pin 3052 is in engagement with second tab 3044.

[0093] FIG. 24 is an isometric cross-sectional view of centralizer 3010. In this view, the intersection of channel 3030 with first ramp 3024 and second ramp 3026 is readily visi ble. It is also seen that spring 3040 is compressed between retaining pins 3050 and 3052.

[0094] FIG. 25 is a cross-sectional side view of centralizer 301 0 that defines a section E-E through which both end positions of the spring may be seen.

[0095] FIG. 26 is an axial cross-section of centralizer 301 0. i llustrated as mounted on tubular 30100. illustrated at a section line that permi ts view ing both tabs 3042 and 3044 of spring member 3040 in relationship to slopes 3024 and 3026. respectively. In this embodiment an exemplar},' angle of 3046 degrees is provided betw een first tab 3042 and CENTER-005 second tab 3044. As seen in FIG. 26, rotation in either direction will have the result of further securing central izer 3010 against tubular 30100.

[0096] FIG. 27 is another axial cross-section of central izer 3010. illustrated as mounted on tubular 30100. i l lustrated at section line E-E, shown with tubular 301 00 rotated clockwise (centralizer 3 10 rotated relatively counterclockwise) and loading spring tab 3042 against ramp 3024 to limit additional relative rotation between tubular 30100 and centralizer 3010.

[0097] FIG. 28 is an isometric view of a second embodiment of a centralizer body 301 10 illustrated in accordance with principles of the present invention described herein. Referring to FIG. 28, centralizer 301 1 0 has a cylindrical body 301 12, comprising an exterior surface 301 14 and stabilizing fins 301 16 extending outwards from exterior surface 301 14. Body 301 12 has a hollow interior w ith an interior surface 301 18, a first edge 30120, and a second edge 30122 formed between exterior surface 301 14 and interior surface 301 1 8.

[0098] A first ramp 301 24 is formed on interior surface 301 1 8, proximate to first edge 301 20, and a second ramp 301 26 is foimed on interior surface 301 1 8, proximate to second edge 30122. A first ramp 30124 is formed on interior surface 301 18, proximate to first edge 30120. A second ramp 30126 is l ormed on interior surface 301 1 8, proximate to second edge 301 26.

[0099] At the position w here first ramp 30124 engages side 3 120, a first slot 30170 is formed. A second slot 30172 is formed where second ramp 30126 engages side 30122.

CENTER-005 [00100] A third ramp 30128 is centrally formed on interior surface 301 18. A first interior circumferential wedge 30134 is formed on interior surface 301 18. and extends between first ramp 30124 and third ramp 30128. A second interior circumferential wedge 30136 is formed on interior surface 301 1 8 and extends between second ramp 30126 and third ramp 301 28. An aperture extends between exterior surface 301 12 and third ramp 301 28.

[00101 ] FIG. 29 is an isometric view of a spring member 30140 for use with centralize! ^" 301 10 of FIG. 28. Expandable spring member 30140 has a first helical section 30142 and a second helical section 30144 connected by a bridge portion 30146. A first tab 30148 extends outward from first helical section 30142. A second tab 301 50 extends outward from second helical section 30144.

[00102] FIG. 30 is an isometric view of centralize! ^" 301 10 illustrated w ith spring member 30140 of FIG. 29 in place. FIG. 3 1 is an isometric cross-sectional vie of centralizer 301 10 as il lustrated in FIG. 30.

[00103] Referring to FIGS. 30 and 31 , it is seen that first helical section 30142 is located on first wedge 30134. Second helical section 30144 is located on second wedge 30136. A retaining pin 301 60 is removably located in aperture 301 36 for engagement with bridge 30146 of spring 30140. As will be seen in FIGS. 29 and 30. slots 301 70 and 301 72 provide a rotational limit for spring 30140 when pre-tensioning spring member 30140 against retaining pin 30160.

|00104] FIG. 32 is a cross-sectional side view of centralizer 301 1 0. In summary of the operation, when retainer pin 301 60 is removed, spring 30140 is preloaded against the surface CENTER-005 of tubular 30100, holding it in place. This prevents axial movement of centralizer 301 10 relative to tubular 30100. Clockwise rotation of tubular 30100 relative to centralizer 301 10 engages tab 30148 between first ramp 30124 and tubular 30100 to limit further rotation. Counterclockwise rotation of tubular 30100 relative to centralizer 301 1 engages tab 30150 between second ramp 30126 and tubular 30100 to limit further rotation. The surface of spring 30140 may be knurled or profiled to increase resistance to sliding relative to tubular 30100.

[00105] FIG. 33 is an isometric view of a third embodiment, being for a lock collar 30200. Lock collar 30200 has all the same inten l al configurations of the self-locking centralizer 301 10 described in the preceding paragraphs, and these components are occasionally numbered the same for reference purposes, but will not otherwise be descri bed herein as their design and operation is the same.

100106] FIG. 33 is an illustration of a body 30212 of lock col lar 30200. Body 30212 has an external surface 30214 and a plurality of body tabs 302 16 extending outward from one end thereof. Body tabs 30216 are separated by intermittent body sl ots 3021 .

[00107] FIG. 34 is an isometric view for a conventional centralizer 30300. Centralizer 30300 has a cylindrical body 3031 2, comprising an exterior surface 30314 and stabilizing fins 30316 extending outward from exterior surface 30314. Body 30312 has a hollow interior with an interior surface 303 1 8 for fitting over a tubular 301 0 (not shown).

[00108] FIG.35 is an end view of lock collar 30200 mounted on centralizer 30300, illustrating body tabs 3021 6 positioned over exterior surface 303 14 of centralizer 30300 and

CENTER-005 between stabilizing fins 30316 of centralizer 30300. In this position, stabilizing fins 30316 are engaged with body slots 30218 of lock collar 30200.

[00109J FIG 36 an isometric vi ew of lock collar 30200 mounted on centralizer 30300. The internal locking system of l ock collar 30200 secures lock collar 30200 to tubular 30100. The engagement of lock collar 30200 with stabilizing fins 30316 of centralizer 30300 works to prevent rotation of centralizer 30300 relative to lock collar 30200 and tubular 30100.

[001 10] FIG. 37 is an i llustration of an exemplary centralizer 40100 in accordance with an embodiment. Referring to FIG. 37, centrali zer 40100 has a cylindrical body 40199, comprising an exteri or surface 401 04 and an inner cavity 40102. Central izer 40100 also comprises a first locking mechanism 40108 and a second lockmg mechanism 401 10. In one embodiment, the first locking mechanism 40108 is a helical spring and the second locking mechanism is a "C ^" shaped spring comprising a rectangular cross section wire (in one embodiment substantially square), which also acts as a slip or wedge when released from its expanded installation position and into its enabled position.

[0011 1 ] In one embodiment, the first locking and second locking mechanism are retained in an expanded, unlocked or disabled position by retaining member 401 12. In one embodiment, retaining member 401 12 is secured by a set screw 401 14. It is appreciated that the set screw ⁷ 401 14 could be any type of retaining device and is not limited to a screw. For example, in one embodi ment, the set screw 401 14 is configured to be uninstalled without requiring the use of a tool and may comprise a pull-tab shaft having a frangible plastic thread (not shown) engaging an interior portion of the body 40199.

CENTER-005 [00112] In one embodiment, removing set screw 401 14 from retaining member 401 12, and from a threaded portion of the body 40199 below the retainer 401 12 (as show n in section in Figure 38) where such removal enables separation of the retaining member from the body 401 9. In response to the retaining member 401 12 being removed, the first and second lock mechanisms are released from the expanded position and automatical ly (due to spring force) move to an enabled or locked position. When installing the centralizer. the centralizer is located in the desired location and the retaining member 401 12 is then removed to allow the centralizer to lock in place.

|001 13] In one embodiment, the centralizer described herein is configured such that the centrali er 40100 can be freely slipped over the outer diameter of a cylindrical member, such as a well pipe, when the locking mechanism(s) is in a disabled, expanded or unlocked position. When the retaining member 401 12 is properly positioned and attached to the body 401 9. the centralizer 401 00 is considered to be in an unlocked or disabled position.

Accordingly, when the retaining member 401 12 is removed from the body 401 99. the centralizer or device 40100 is considered to be in a locked or enabled position. A direction indicator 401 1 can be used to aid in installation of the centralizer 401 00 by showing a proper orientation of installation relative to the well pipe.

[001 14] In one embodiment, the inner surface 40102 of housing 401 99 comprises a tapered inner diameter, such that the inner diameter of the housing is larger proximate a central position of the inner diameter, as measured in an axial direction from end to end of the centralizer, and smaller towards an outer edge of the inner diameter of the housing. This inner surface may have a variable diameter such that it is tapered and creates a space that provides room for one or more locking expanded mechanisms. Such a tapered inner surface CENTER-005 can be seen in area 40204 of FIG. 38. In one embodiment, the angle of the taper is in the range of 10-25 degrees. In one embodiment, the inner surface is conical and the angle of the taper with respect to the housing's axis is in the range of 10-25 degrees. In another embodiment the inner surface is toroidal, and the angle of the taper with respect to the housings axis varies from between 0 - 15 degrees on end and 1 -60 degrees on the other end.

[00115] In one embodiment, the first lock mechanism 40108 comprises a spring. The spring may include one or more coils of spring w ire that are configured to slide freely over an outer diameter of pipe when in an expanded or disabled position and configured to provide a gripping or frictional force betw een the centrali/er 40100 and an outer surface of a pipe when in an enabled or semi-relaxed position. When the retaining member is installed, the first spring mechanism is in a retracted or disabled position and can slide freely over an outer surface of a pipe section. Once the retaining member 401 12 is removed, the first spring mechanism moves to a semi-relaxed or enabled position and provides a frictional force on an outer surface of a pipe section that restricts axial movement of the centrali/er with respect to the pipe section. In one embodiment, the first spring mechanism or first locking mechanism 108 includes a helically wound flat wire spring.

[00116] In one embodiment, the inner surface 40204 of the centralizer includes a recess diameter area 40173 proximate a mid-portion as measured axially from either end of the centralizer. The recess diameter area 401 73 comprises a secti on of inner di ameter slightly greater than adjacent inner diameter. The axial width of the recess diameter area 4 1 73 is slightly greater than the stack w idth of the locking mechanisms. In one embodiment shown in Figure 38 the recess diameter area 40273 length is sl ightly greater than the slack height of the expanded and retained first locking mechanism 401 08 and two second locking mechanisms CENTER-005 401 10. As shown the recess diameter is bordered at each end by a shoulder portion 40156 of the inner surface 40204. The shoulder portion 40156 helps retain the first locking mechanism 40108 and/or the second locking mechanism 401 10 in a tightly stacked (axially) position within the centralizer when the locking mechanisms are expanded tightly against the inner diameter of the recess.

[00117] In one embodiment, the second lock mechanism 40110 comprises a spring which may function as a slip or wedge for operating in conjunction with a tapered surface 40102 or 40204 of the inner diameter of the centralizer for enhanced gripping of the well pipe when the sl ip spring is enabled. The slip spring may include one or more lengths of wi re that are configured to sl ide freely over an outer diameter of pipe when in an expanded or retracted (to a larger inner diameter) position and configured to provide a gripping force between the centralizer 401 00 and an outer surface of a pipe when in an enabled or semi-relaxed (toward a smal ler inner diameter) position. While in the retracted position, one or more surface, such as open end surfaces (e.g. 40306. 40308) of the slip spring may abut against one or more portion of the retaining member where the interposition of the retaining member 401 12 between the open end surfaces retains an expanded condition in the spring such that the spring assumes a larger diameter and a stored energy state. When the retaining member is removed, the stored energy causes the spring to move toward a smaller (semi-relaxed) diameter condition, w hich in use will place it in contact with a pipe on which the centralizer is being instal led.

[001 IS] In one embodiment, the slip spring has one or more gripping edges 40135 that provide a gripping force that impedes motion of the centralizer with respect to a wel l pipe. A gripping edge could be an edge of machined grooves or could be an edge of a square or CENTER-005 rectangular wire, for example. When the retaining member is installed, the second spring mechanism 401 10 is in a retracted (expanded by interposition of retaining member as described above) or disabled position and can slide freely over an outer surface of a pipe section. In one example embodiment, one or more portion of the first and/or second spring mechanisms comprises hardened metal such as spring steel . For example, in one embodiment, the gripping surfaces of the first and second locking mechanisms have a Rockwell C scale hardness of at least 30. In one embodiment, the gripping surfaces of the first and second locking mechanisms have a Rockwell C scale hardness between 40-45.

[001 19] Once the retaining member 401 12 is removed, the second spring mechanism 401 1 0 is in a semi-relaxed or enabled position and provides a frictional or gripping force on an outer surface of a pipe section that restricts movement of the centralizer with respect to the pipe section. In one embodiment, the second locking mechanism 401 10 restricts rotational movement of the centralizer with respect to the pipe section. In this embodiment, (he slip spring descnbed above may be formed in and / a twisted or helical configuration.

[00120] For example, in the case the slip spring is formed from a square wire, the square wire would be twisted helically wherein the corners of the square wire become gripping edges that are disposed helically along a circumferential length of the slip spring. When in an engaged position, the helically disposed gripping edges dig into an outer surface of a wellbore pi pe and prevent rotational movement of the centralizer with respect to the well bore pipe.

[00121 ] In another embodiment, the second locking mechanism 401 10 restricts axial movement of the centralizer with respect to the pipe section. In this embodiment, the slip CENTER-005 spring described above may be disposed as a non-twisted square or rectangular wire. For example, in FIG. 38, the slip spring 401 10 is formed from a non-twisted square wire and one or more corners formed by grooves on the inner surface of the square wire become gripping edges that prevent axial movement of the centralizer with respect to a wellbore pipe.

[00122] In one embodiment, the second spring mechanism includes a square or rectangular wire and in one embodiment, the square or rectangular wire is twisted and formed in a helix shape. In this embodiment, the edges of the twisted square or rectangular wire form a helix and the edges of the helix provide a frictional force between the centralizer bod}- 401 9 and the outer surface of a pipe section.

[00123] In one embodiment, the outer surface 40104 of the centralizer body comprises one or more ridges or blades 40106 that are contoured to induce a non-laminar flow of material, such as casing cement that flows past the cenlralizer 401 00 when installed on a pipe section within a borehole. In one embodiment, the blades 40106 direct material, such as casing cement, in multiple directions when flowing past the centralizer. In one embodiment, the ridges 40106 facilitate proper cementing and reduce problems such as cement channeling within a borehole.

[00124] In one embodiment, one or more blades 40106 are of a tapered or teardrop profile. For example, the blades may have an apparent outer diameter that is larger at one end of the centralizer than the other and a taper or teardrop profi le may extend between the differing diameter ends. In one embodi ment the larger outer diameter is configured to be on the lower or down-hole side of the centralizer as the well pipe is lowered into the well bore. Such a configuration helps to minimize the possibility of wedge sticking of the centralizer in tight

CENTER-005 well diameters or "keyholes. ^" In one embodiment a central portion (toward the axial middle, end to end of the centralizer) of the blades includes a reduced apparent outer diameter to facilitate decreased fluid by pass pressure drop during the running of pipe into the well or fluid circulation such as cementing operations.

[00125] FIG. 38 shows a sectional view of centralizer 40100 having the first locking mechanism 40108 and the second locking mechanism 401 10 in an expanded position. In FIG. 38. the first locking mechanism 40108 comprises a plurality of helically wound coils 401 23. The helical ly wound coi ls 40123 of 401 08 are rectangular in cross section. The inner diameter edge 401 56 of the w ire includes a substantially sharpened edge and the "flat ^" wire comprises spring steel having, in one embodiment, a Rockwell C scale hardness of 38-42. The second locking mechanism is shown to comprise at least one substantially rectangular wire ring 401 10. The embodiment of Figure 38 includes a rectangular or semi-rectangular cross section ring 401 10 on each axial side of the first locking mechanism 40108. The wire ring 401 10 includes at least one raised and substantially sharp circumferential reduced contact area gripping profi le 401 35 having the form of a "tooth ^" or "wicker ^" profi le 401 35 for enhanced gripping of an exterior of a well pipe on which the centralizer is install ed. In one embodiment the raised wicker comprises a material having a Rockwell C scale hardness of 38-42.

|00126] Retaining member 401 12 retains the first and second lock mechanisms in a retracted position. In the retracted position, an inner diameter 4021 of the first and second lock mechanisms is larger than the outer diameter of a well bore pipe which allows the centralizer 401 00 to be freely positioned axially along a length of well bore pipe.

CENTER-005 [00127] When the retaining member is removed, the first lock mechanism 40108 is allowed to contract to an enabled or locked position and the resulting inner diameter 40410 of the more relaxed spring coils in the enabled position is smaller than the inner diameter 40210 when in the retracted (expanded due to reaction force retaining strain energy within the spring and applied axial ly at the ends of the coiled or circumferentially bent spring wire) or disabled position.

[00128] The smaller diameter in the locked position results in the spring coils of the first locking mechanism gripping the outer surface of a wellbore pipe with a frictional force that restricts movement of the centralizer with respect to the w el lbore pipe w hen in the engaged or locked position. In one embodiment, the first locking mechanism 401 08 restricts axial movement o the centralizer with respect to a wellbore pipe. In one embodiment the coil or coils of 40108 "lean ^" slightly when subjected to relative axial movement between the outer housing and the wellbore pipe. When such coi ls 108 are so ^" leaned ^" or canted in a pal l like fashion, the edges, in one embodiment sharp and hardened (e.g. 40 RC). of the coil bite into the outer diameter of the wellbore pipe thereby increasing the gripping load that can be borne by the locking mechanism 40108.

[00129] In one embodiment, when the retaining member, which also holds the second lock mechanism in an expanded position via axial reaction force applied to the spring wire as described above, is removed, the second lock mechanism 401 10 is allowed to contract to an enabled or locked positi on and the resulting inner diameter of the lock ring in the enabled position is smaller than the inner diameter when in the retracted or disabled position. The smaller inner diameter in the locked position results in the lock ring o the second locking mechanism gripping the outer surface of a wellbore pipe with a frictional or gripping force CENTER-005 that restricts movement of the centraiizer with respect to the wellbore pipe when in the engaged or locked position.

[00130] In one embodiment, the second locking mechanism 401 10 includes a

circumferentially bent or ^" coiled ^" (e.g. ^" coiled ^" in at least one partial coi l) helically twisted square or rectangular wire member thai restricts rotational movement of the centraiizer with respect to a wellbore pipe. In another embodiment, the second locking mechanism 401 10 includes a coiled non-twisted square or rectangular wire member that augments the force of the first locking mechanism and also restricts axial movement of the centraiizer with respect to a wellbore pipe

[00131] In one embodiment, the inner surface 40102 of the centraiizer body 40199 includes at least one tapered inner diameter surface 40204 and as shown may include a tapered surface on each side of the center locking mechanism recess area. In one embodi ment the tapered surface comprises a non-linear (e.g. not straight taper) diameter surface 40204 that includes a variable diameter. The tapered surface, w hether straight or non-linear, is configured to interact with a portion of the second l ocki ng mechanism such that the second locking mechanism becomes wedged between the tapered surface 40204 of the centraiizer body 401 9 and an outer surface of a wellbore pipe. Axial movement of the centraiizer body 401 9 relative to the pipe wil l further w edge the second locking mechanism between the diminishing inner diameter of the taper and the outer diameter of the w ell pipe. An axial wedge mechanism as descri bed herein w ould however operate in a conceptual ly similar fashion.

CENTER-005 [00132] In one embodiment the non-linear taper forms an inner diameter than decreases at an increasingly rapid rate (such as for example a curve of exponentially decreasing radius) as it progresses toward an end of the centralizer. In one embodiment the angle of the taper, relative to the central axis of the centralizer. toward the inner end or center of the tapered section is 5 degrees and toward the outer end of the tapered section is 30 degrees or greater. The increasing angle faci litates a reduced radial load component (resulting from the wedging), in relation to axial load on the centralizer body, on the second locking mechanism thereby reducing any l ikelihood that the well pipe will be collapsed locally or that the centrali zer body wi ll be burst local ly by the radial wedge loading of the second locking mechanism. The curve or angle variation of the taper may be designed to optimize gripping load w hi le minimi zing the possibi l ity of failed casing or centralizer body due to overloading of the w edge under high axial centralizer load (as might occur when ninning the centralizer into a down-hole obstruction w hile low ering pipe into the wellbore).

|00133] In one embodi ment, the first 401 08 and second 401 1 locking mechanisms are activated in stages. The first locking mechanism performs as a first stage lock and the second locking mechanism performs as a second stage lock wherein the second stage lock augments the force applied by the first stage lock to restrict movement of the centralizer with respect to a w ell bore pipe.

|00134) In one embodiment, the second locking mechanism 401 10 is w edged in response to an axial force being applied to a centralizer outer body that is initial ly held to a wellbore pipe by the first locking mechanism 401 08. When both the first and second locking mechanisms are deployed into gripping engagement with an outer diameter of the wellbore pipe the first locking mechanism may. in one embodiment, move axially within the centralizer outer body. CENTER-005 When an axial force overcomes the gripping force applied by the first locking mechanism, the central izer may then shift axially along the wellbore pipe. The first locking mechanisms will tend to stay engaged with the well pipe and retain its axial location thereon. As the outer centralizer body moves, taking the first second locking mechanisms axially therewith, one of the second locking mechanisms (corresponding to the end of the centralizer body moving closer to the first locking mechanism) will abut the first locking mechanism and be retained thereby even as the centralizer body continues to move. As the centralizer body moves relative to the retained second locking mechanism, that mechanism will be forced into the inner diameter wedge section of the centralizer body and will be wedged into tight gripping engagement with the outer surface of the w ell pipe. As such the second locking feature augments the first locking mechanism by providing an additional griping force that resists movement.

[00135] In one embodiment, when the second locking mechanism includes a non-twisted member, the second locking member restricts axial movement of the centralizer with respect to a wellbore pipe. In another embodiment, w hen the second locking mechanism includes a twisted member, the second locking member restricts axial and rotational movement of the centralizer with respect to a wellbore pipe. It is appreciated that the second locking mechanism may restrict axial and / or rotational movement of the centralizer with respect to a well bore pipe in one or more directions.

|00136] In one embodiment, the centralizer body 401 9 comprises a substantial ly cylindrical outer body having a first inner diameter at each end thereof and a second inner diameter located intermediate of the ends, wherein the second inner diameter is greater than the first inner diameter. This is shown in FIG. 38 as the inner diameter of the centralizer CENTER-005 body 40199 is larger proximate the locking mechanisms 40108 and 401 10 than the inner diameter of the centralizer body near the ends. This difference in diameters creates a surface 40204 that is configured to interact with the second locking mechanism to wedge a portion of the second locking mechanism between the outer surface of a wellbore pipe and the inner surface of the centralizer.

[00137] In one embodiment, the first locking mechanism comprises a spring that comprises a helically wound wire having at least one coil and a first wire end and a second wire end and is positioned substantially co-axially within the centralizer body and proximate the larger inner diameter of the centralizer housing. In one embodiment, the spring has a spring expanded position such that an inner di ameter of the at least one coil of the spring is substantially equal to or greater than the smaller inner diameter at either end of the centralizer housing and also has a spring released position such that the inner diameter of the at least one coil would be smal ler than the inner diameter at either end of the centralizer housing were the spring unrestrained.

[00138] As shown in FIGS. 39 through 40C. in one embodiment, the retainer member 401 12 has a first retainer position wherein it extends through apertures 40209 and 40209a in the outer body 401 9 and has a leg portions 4021 and 4021 a abutting at least one of the first 40302 and second 40304 wire ends of a first spring locking mechanism such that the spring is restrained in the spring expanded position and also has a second retainer position as indicated in FIG. 40C wherein at least one of the leg porti on is removed from abutment with the at least one of the first and second wire ends such that the spring may move to its spring released position.

CENTER-005 [00139] In one embodiment, the coil spring of the fu st locking mechanism is helically wound with the first wire end 40304 pressing on or abutted against retainer leg portion 40219a from a first direction and the second wire end 40302 pressing or abutting against the retainer leg portion 40219 from a second direction that is opposite the first direction. The opposing forces of the wire ends 40302 and 40304 induce reactive loads within the retainer leg portions 40219 and 4021 a in the retracted position or unlocked position of the first locking mechanism.

[00140] FIGS. 40A, 40B and 40C are perspective views showing various locking states that are controlled by the retaining member 401 12. For clarity, only the first locking mechanism 108 is shown, however, it is appreciated that the retaining member 401 12 could also control similar locking states of the second locking mechanism 401 10 and an inner diameter 40210 of the w ire spring is maintained.

|00141 ] FIG. 40A shows an initial unlocked or disabled-state where the retaining member 401 12 is fully positioned in the central izer housing and abuts a first wire end 40302 and a second wire end 40304 to keep the first locking mechanism in a retracted (diameter expanded) state. In the retracted or disabled stale, wire end 40302 presses against the retaining member in direction 40402A and wire end 40304 presses against the retaining member in direction 40404A.

[00142] FIG. 40B shows an intermediary state where the retaining member is partial ly removed from the centralizer housing while still abutting the first wire end 40302 and the second wire end 40304 to keep the first locking mechanism in a diameter expanded (retracted state). In the intermediary state, wire end 40302 still presses or abuts against the retaining CENTER-005 member in direction 40402B and wire end 40304 presses against the retaining member in direction 40404B.

[00143] FIG 40C shows a locked or enabled state (diameter semi-relaxed to engage well pipe) where the retaining member is fully removed from the centralizer housing. When the retaining member 401 12 is removed, the locking device automatically moves into and remains in a locked or enabled position w ithout requiring an additional outside applied force. Figure 40C shows the first wire end 40302 and the second wire end 40304 in a locked or enabled state. In the enabled state, wire end 40302 may overlap wire end 40304. The overlapping of the wire ends 40302 and 40304 results in the smaller inner diameter 40410 of the wire spring compared to its diameter 402 10 in the disabled state described above. The reduced inner diameter of the wire spring provides a gripping force to resist movement of the centralizer with respect to a wellbore pipe

[00144] FIG. 41 shows a side view centralizer 401 00 having a second locking mechanism 401 10 with a twisted wire member. In this example, a twisted square or rectangular wire slip spring is used to resist rotational movement of the centralizer with respect to a well bore pipe. As provided above, the second lock mechanism of FIG. 38 included a non-twisted slip spring that resists axial movement of the centi alizer with respect to a wellbore pipe. With respect to FIG. 41 , the twisted or helix form of the slip spring of the second locking mechanism 401 10 provides a gripping force on a well bore pipe that resists rotational and axial movement of the centralizer 401 00 with respect to the well bore pipe when in an enabled position.

[00145] In one embodiment, the retainer member 401 12 has a first retainer position wherein it extends through an aperture 40209 in the outer body 401 9 and has a leg portion 40219 abutting at least one of a first and second wire ends of the second lock mechanism 401 10 CENTER-005 such that slip spring is restrained in an expanded position and also has a second retainer position wherein the leg portion is removed from abutment with the at least one of the first and second wire ends such that the spring may move to its spring released position.

[00146J In one embodiment, the wellbore pipe centralizer 40100 comprises a substantially cylindrical outer body 4 1 9 having a first inner diameter 4021 1 at each end thereof and a second inner diameter located intermediate of the ends, wherein the second inner diameter is greater than the first inner diameter. FIG. 37 shows the tapered surface of the inner surface 4 1 02 of the outer body that forms a tapered surface or "non-planar" section 40204.

[00147J The well pipe centralizer 40100 further comprises a spring 40108 comprising a helically wound wire having at least one coil and a first wire end 40302 and a second wire end 40304, positioned substantially co-axially within the outer body 40199 and proximate the second diameter, the spring 40108 having a spring expanded position (shown in FIG. 40A) such that an inner diameter of the at least one coil of the spring is substantially equal to or greater than the first diameter, and having a spring released position (shown in FIG. 40C) such that the inner diameter of the at least one coil would be smaller than the first diameter were the spring unrestrained.

[00148] The well pipe centralizer further comprising a retainer member 401 12 having a first retainer position (Shown in FIG. 40A) wherein it extends through an aperture 40209 in the outer body 401 9 and has a leg portion 40219 abutting at least one of the first and second wire ends such that the spring is restrained in the spring expanded position and having a second retainer position (shown in FIG. 40C) wherein the leg portion is removed from

CENTER-005 abutment with the at least one of the first and second wire ends such that the spring may move to its spring released position.

[00149] In one embodiment, the outer body of the wellbore pipe central i/.er further includes at least one inner diameter taper (shown in area 40204 of FIG. 38) located axially between the second inner diameter and at least one of the first inner diameters, and wherein the centralizer further comprises a slip spring 401 10. positioned substantially co-axially within the outer body and proximate the spring, and having a slip spring expanded position such that an inner diameter of the slip spring is substanti al ly equal to or greater than the first diameter, and having a slip spring released position such that the inner diameter of the slip spring would be smaller than the first diameter were the slip spring unrest ained.

[00150] In one embodiment, the slip spring 401 10 comprises at least one circumferentially distributed pipe gripping edge, and a first slip wire end and a second slip wire end In one embodiment, the pipe gripping edge is proximate an inner diameter of the slip spring.

[00151] In one embodiment, the slip spring 401 1 0 is restrained in the slip spring expanded position (shown in FIG. 40A) by one of the retainer and a second retainer.

[00152] In one embodiment, the slip spring 401 10 is movable betw een a first taper location and a second taper location (for example, area 40204) when the slip spring is in the slip spring released position and where (he first taper location inner diameter is greater than the second taper location inner diameter.

CENTER-005 [00153] In one embodiment: the slip spring 401 10 comprises wire having a substantially rectangular cross-section as shown in FIG. 38. In one embodiment, the slip spring 401 10 comprises a ci cumierential body having at least one raised portion including the gripping edge thereon.

[00154] FIG. 41 shows a side vie of an exemplars' central izer having a gripping edge that is helically disposed about a circumference of the slip spring.

|00155] In one embodiment, the centrali/er includes a first inner diameter taper and a first slip-spring movable therein, w herei n the first slip spring is movable between an initial first taper location 40225 of FIG. 41 and an ending first taper location 40235 of FIG. 41 when the first slip spring is in the slip spring released position and where the initial first taper location inner diameter is greater than the ending fi rst taper location inner diameter, and a second inner diameter taper and a second sli spring movable therein, wherein the second slip spring is movable between an initial second taper location and an ending second taper location when the second slip spring is in the slip spring released position and where the initial second taper location inner diameter is greater than the ending second taper location inner diameter.

[00156| In one embodiment, the spring 1 08 comprises a flat wire spring as shown in FIGS. 38 and 41 . In one embodiment, the flat wi re spring is wound having its long cross sectional axis substantially aligned in a radial direction and further where the flat wire spring includes at least one sharp gripping edge proximate the inner diameter.

CENTER-005 (00157] In one embodiment, one or more components of the centralizer 40100 are hardened. For example, in one embodiment, the flat wire 40108 comprises spring steel having a Rockwell C scale hardness of at least 40.

|00158] In one embodiment, the second locking mechanism includes at least one twisted square wire (shown in FIG. 41 ) having a first wire end and a second wire end and positioned proximate the second diameter, the twisted square wire configured to provide a gripping force between an inner surface of the outer bod)' of the wellbore pipe centralizer and an outer surface of the well bore pipe when the first wire end and the second wire ends are in a released position.

[00159] In one embodiment, the outer body 40199 comprises at least one ridge 40106 on an outer surface for inducing a non-laminar flow of material past the centralizer. For example, once a centralized pipe is disposed within wel lbore. cement is used to secure the pipe within the borehole. The cement is disposed between the well pipe and the borehole. The ridges 401 6 direct the flow of cement in multiple directions to improve cement flow ⁷ and to reduce the chances of improper cementing.

|00160| In one embodiment, the retainer member 401 12 is removably coupled to the substantially cylindrical outer body by a retaining nut 401 14.

|001611 In one embodiment, the locking centralizer 401 00 includes a multiple stage locking system that includes a first stage lock 40108 configured such that when in a first unlocked position, the first stage lock allows axial movement of the cylindrical housing with respect to the tubular member and when in a locked position, the first stage lock provides a first CENTER-005 gripping force that restricts axial movement of the housing with respect to the tubular member. The locking centralizer also includes a second stage lock 401 10 configured such that when in a second locked position, the second stage lock provides a second gripping force that further prevent the axial movement of the housing with respect to the tubular member, the second gripping force also restricts movement of the locking centralizer with respect to the tubular member.

METHODS OF OPERATION

[00162] FIG. 42 is a flow diagram of an exemplary method 40600 for attaching a centralizer to a tubular member. In one embodiment method 40600 is perfomied without requiring the use of an applied force to secure the centralizer to the tubular member.

[00163] At 40602, method 40600 includes placing a central izer housing onto a tubular member, the cenlralizer housing comprising an inner cavity con figured to slide over an outer surface of the tubular member, the housing comprising an outer surface for centering the tubular member within a borehole.

[00164] At 40604, method 40600 includes accessing a first locking mechanism coupled w ith the inner cavity, the first locking mechanism configured such that when retained in a retracted position by a retaining member, the locking mechanism allows axial movement of the cenlralizer housing with respect to the tubular member and when the retaining member is removed and the first locking mechanism is in an enabled position, the locking mechanism provides a gripping force that restricts axial movement of the housing with respect to the tubular member.

CENTER-005 [00165] At 40606, method 40600 includes releasing the retaining member to attach the centralizer to the tubular member.

|00166] In one embodiment, method 40600 also includes axially moving the centralizer housing with respect to the tubular member and engaging a second locking mechanism coupled with the inner cavity and configured such that when in a locked position, the second locking mechanism provides a second gripping force that further restricts the axial movement of the centralizer housing with respect to the tubular member.

[00167] In one embodiment, method 40600 further includes preventing rotation of the centralizer with respect to the tubular member with the second locking mechanism.

[00168] In one embodiment, the first locking mechanism moves to the enabled position without requiring use of an applied force.

[00169] FIG. 43 is a flow diagram of an exemplary method 40700 method for using a well bore pipe central izer. At 40702, method 40700 includes positioning a central izer housing onto a wellbore pipe, the centralizer housing comprising an inner cavity configured to slide over an outer surface of the wellbore pipe, the housing comprising an outer surface for centering the wellbore pipe within a wel lbore.

[00170] At 40704. method 40700 includes accessing a first locking mechanism coupled with the inner cavity, the first locking mechanism configured such that when retained in a retracted position by a retaining member, the locking mechanism enables free movement of the central izer housing with respect to the wel l bore pipe and when the retaining member is CENTER-005 removed and the first locking mechanism is in an enabled position., the first locking mechanism provides a frictional force between the wellbore pipe and the centrahzer housing that restricts axial movement of the centrahzer housing with respect to the wellbore pipe.

[00171 ] At 40706, method 40600 includes removing the retaining member to attach the centrahzer to the wellbore pipe.

[00172] At 40708, method 40700 includes moving axially the centrahzer housing with respect to the wel lbore pipe.

[00173] At 407 10. method 40700 includes engaging a second locking mechanism coupled with the inner cavity and configured such that when in an unlocked position, the second locking mechanism provides a second gripping force that restricts rotational movement of the centrah zer housing with respect to the wellbore pipe.

[00174j In one embodiment, method 40700 includes the first locking mechanism moving to the enabled position without requiring an applied force.

[00175| In one embodiment, method 40700 includes maintaining the first locking mechanism in the enabled position without requiring an applied force.

Example Embodiments

[00176] In one embodiment, a wellbore pipe centrahzer includes a substantially cylindrical outer body having a first inner diameter at each end thereof and a second inner diameter located inteimediate of the ends, wherein the second inner diameter is greater than the first CENTER-005 inner diameter; a spring comprising a helically wound wire having at least one coil and a first wire end and a second wire end. positioned substantially co-axially within the outer body and proximate the second diameter, the spring having a spring expanded position such that an inner diameter of the at least one coil of the spring is substantial ly equal to or greater than the first diameter, and having a spring released position such that the inner diameter of the at least one coil would be smaller than the first diameter were the spring unrestrained; and a retainer member having a first retainer position w herein it extends through an aperture in the outer body and has a leg portion abutting at least one of the fi rst and second wire ends such that the spring is restrained in the spring expanded position and having a second retainer position wherein the leg portion is removed from abutment with the at least one of the first and second wire ends such that the spring may move to its spring released position.

[00177] In one embodiment, the outer body further includes at least one inner diameter taper located axially between the second inner diameter and at least one of the first inner diameters, and wherein the centralizer further comprises a sli p spring, positi oned substantially co-axially within the outer body and proximate the spring, and having a sli p spring expanded position such that an inner diameter of the slip spring is substanti al ly equal to or greater than the first diameter, and having a slip spring released position such that the inner diameter of the slip spring would be smaller than the first diameter w ere the slip spri ng unrestrained.

|00178] In one embodiment, the slip spring comprises at least one circumferential ly distributed pipe gripping edge, and a first slip w ire end and a second slip wire end.

[00179] In one embodiment, the pipe gripping edge is proximate an inner diameter of the slip spring.

CENTER-005 [00180] In one embodiment, the slip spring is restrained in the slip spring expanded position by one of the retainer and a second retainer.

[00181 ] In one embodiment, the slip spring is movable between a first taper location and a second taper location when the sl ip spring is in the slip spring released position and where the first taper location inner diameter is greater than the second taper location inner diameter.

[00182] In one embodiment, the slip spring comprises wire having a substantially rectangular cross-section.

[00183] In one embodiment, the gripping edge comprises at least one corner edge of the wire.

[00184] In one embodiment, the slip spring comprises a circumferential body having at least one raised portion incl uding the gripping edge thereon.

[00185] In one embodiment, the gripping edge is helically disposed about a circumference of the sli p spring.

[00186] In one embodiment, the well bore pipe centralizer further comprising a first inner diameter taper and a first sl ip-spring movable therein, wherein the first slip spring is movable between an initial first taper location and an ending first taper location when the first slip spring is in the slip spring released position and where the initial first taper location inner diameter is greater than the ending first taper location inner diameter, and a second inner CENTER-005 diameter taper and a second slip spring movable therein, wherein the second slip spring is movable between an initial second taper location and an ending second taper location when the second slip spring is in the slip spring released position and where the initial second taper location inner diameter is greater than the ending second taper location inner diameter.

|00187] In one embodiment, the spring comprises a flat wire spring.

[00188] In one embodiment, the flat wire spring is wound having its long cross sectional axis substantially aligned in a radial direction and further where the flat wire spring includes at least one sharp gripping edge proximate the inner diameter.

[00189] In one embodiment, the flat wire comprises spring steel having a Rockwell C scale hardness of at least 40.

[00190] In one embodiment, the wellbore pipe centralizer further comprises at least one twisted square wire having a first wire end and a second wire end and positioned proximate the second diameter, sai d tw isted square wire configured to provide a gripping force betw een an inner surface of said outer body of said wellbore pipe centralizer and an outer surface of the wellbore pipe when said first wire end and said second wire ends are in a released posi tion.

[00191 ] In one embodiment, the substantially cylindrical outer body comprises at least one ridge on an outer surface for inducing a non-laminar flow of material past said centralizer.

CENTE -005 [00192] In one embodiment, the retainer member is removably coupled to said substantially cylindrical outer body by a retaining nut.

[00193] In one embodiment, the spring is configured to move to said second released position by a spring force of said spring

[00194] In one embodiment, the spring is configured to remain in said second released position without requiring an outside force.

[00195] In one embodiment, the wel l bore pipe centralize! ^' comprises a substantially cylindrical outer body having a first inner diameter at each end thereof and a second inner diameter located intermediate of the ends, wherein the second inner diameter is greater than the first inner diameter; a spring comprising a circumferential body having a first circumferential axis end and a second ci rcumferential axis end, the spring positioned substantially co-axially within the outer body and proximate the second diameter, and further having a spring expanded position such that an inner diameter of the spring is substantially equal to or greater than the first diameter, and having a spring released position such that the inner diameter of the spring would be smaller than the first diameter were the spring unrestrained; and a retainer member having a first retainer positi on wherein it extends through an aperture in the outer body and has a leg portion abutting at least one of the first and second circumferential axis ends such that the spring is restrained in the spring expanded position and having a second retainer position wherein the leg portion is removed from abutment with the at least one of the first and second circumferential axis ends such that the spring may move to its spring released position.

CENTER-005 [00196] In one embodiment, a lockmg centralizer comprises a housing with an inner cavity configured to slide over an outer surface of a tubular member, said housing comprising an outer surface for centering said tubular member within a borehole; a first locking mechanism coupled with said inner cavity and configured such that when in a disabled position, said first locking mechanism does not prevent axial movement of said housing with respect to said tubular member and when in an enabled position, said first locking mechanism provides a first gripping force that restricts axial movement of said housing with respect to said tubular member: and a second locking mechanism coupled with said inner cavity and engageable concurrently with said first locking mechanism that when in an enabled position, said second locking mechanism augments said first gripping force of said first locking mechanism and further restricts movement of said housing with respect to said tubular member.

[00197] In one embodiment, the second locking mechanism provides a second gripping force that restricts axial movement of said housing with respect to said tubular member.

[00198] In one embodiment, the second locking mechanism provides a second gripping force that restricts rotational movement of said housing with respect to said tubular member.

[00199] In one embodiment, the first locking mechanism comprises a flat wire spring.

[00200] In one embodiment, the second locking mechanism comprises at least one twisted square wire.

CENTER-005 [00201 ] In one embodiment, the locking centralize! ^' further comprising a lock retainer coupled with said housing and configured for securing said first locking mechanism and said second lock mechanism in disabled positions.

|00202] In one embodiment, the lock retainer is removable and configured for al lowing enablement of said first locking mechanism and configured for allowing enablement of said second lock mechanism when removed from said housing.

|00203] In one embodiment, the first locking mechanism and said second locking mechanism are enabled simultaneously in response to removing said lock retainer.

[00204] In one embodiment, the inner cavity of said housing comprises a variable diameter surface that w edges said second locking mechanism against said outer surface of said tubular member.

[00205J In one embodiment, axial movement of the housing impinges the second locking mechanism axially against the first locking mechanism thereby further w edging the second locking mechanism against the outer surface of the tubular member.

[00206) In one embodiment, the outer surface of said housing further comprises at least one ridge for inducing flo ' turbulence in material flow ing past said locking central i/er.

[00207] In one embodiment, the first locking mechanism is configured to move to said enabled position without requiring a force externally applied to the housing.

CENTE -005 [00208] In one embodiment, the first locking mechanism is configured to remain m said enabled position without requiring an externally applied force.

[00209] In one embodiment, a locking central izer compri ses a cylindrical housing with a concaved inner surface configured to house a locking mechanism that is configured to slide over an outer surface of a tubular member, said cylindrical housing comprising an outer surface for centering said tubular member within a borehole; said a locking mechanism comprising: a first stage lock configured such that w hen in a first unlocked position, said first stage lock allows axial movement of said cylindrical housing with respect to said tubular member and when in a locked position, said first stage lock provides a first gripping force that restricts axial movement of said housing w ith respect to said tubular member; and a second stage lock configured such that when in a second locked position, said second stage lock provides a second gripping force that further prevent said axial movement of said housing with respect to said tubular member, said second gripping force also restricts movement of said locking central izer with respect to said tubular member.

[00210] In one embodiment, the second stage lock restricts rotational movement of said locking centralize!" with respect to said tubular member.

[0021 1 ] In one embodiment, the second slage lock comprises one or more helical ridges that restrict said rotational movement of said locking centralizer with respect to said tubular member.

[00212] In one embodiment, the first stage lock comprises a heli cally wound fiat wi re spring with at least one coil.

CENTER-005 [00213] In one embodiment, the second locking mechanism comprises at least one twisted square wire.

[00214] In one embodiment, the twisted square wire comprises hardened metal.

[00215] In one embodiment, the locking centralizer further comprising a lock retainer coupled with said cylindrical housing and configured for securing said first stage lock and said second stage lock in disabled positi ons.

[00216] In one embodiment, the lock retainer is removable and configured for enabling said first stage lock and enabling said second stage lock when removed from said housing.

[00217] In one embodiment, the first stage lock and said second stage lock are engaged simultaneously in response to removing said lock retainer.

[00218] In one embodiment, the concaved inner surface of said housing comprises a variable diameter surface that wedges said second stage lock against said outer surface of said tubular member.

[00219| In one embodiment, the outer surface of said housing further comprises at least one ridge for inducing a non-laminar flow of material past said locking centralizer.

[00220] In one embodiment, the first locking mechanism is configured to move to said locked position without requiring an applied force.

CENTER-005 [00221] In one embodiment, the first locking mechanism is configured to passively remain in said locked position without requiring an outside force.

[00222] In one embodiment, a method for attaching a centralizer to a tubular member is

provided. The method includes placing a centralizer housing onto said tubular member, said centralizer housing comprising an inner cavity configured to slide over an outer surface of said tubular member, said housing comprising an outer surface for centering said tubular

member within a borehole; accessing a first locking mechanism coupled with said inner

cavity, said first locking mechanism configured such that when retained in a retracted

position by a retaining member, said locking mechanism allows axial movement of said

centralizer housing with respect to said tubular member and when said retaining member is removed and said first locking mechanism is in an enabled position, said locking mechanism provides a gripping force that restricts axial movement of said housing with respect to said

tubular member; and releasing said retaining member to attach said centralizer to sai d tubular member.

[00223] In one embodiment, the method further comprises axial ly moving said centralizer housing with respect to said tubular member; and engaging a second locking mechanism

coupled with said inner cavity and configured such that when in a locked position, said

second locking mechanism provides a second gripping force that further restricts said axial movement of said central izer housing with respect to said tubular member.

[00224] In one embodiment, the method further comprises preventing rotation of said

centralizer with respect to said tubular member with said second l ocking mechanism. *

CENTER-005 [00225] In one embodiment, the first locking mechanism moves to said enabled position without requiring use of said applied force.

[00226] In one embodiment, the first locking mechani sm remains in said enabled position without requiring said applied force.

[00227] In one embodiment, a method for using a w ellbore pipe centralizer is provided. The method includes positioning a centralizer housing onto said well bore pipe, said centralizer housing comprising an inner cavity configured to slide over an outer surface of said wellbore pipe, said housing comprising an outer surface for centering said wellbore pipe within a wellbore; accessing a first locking mechanism coupled w ith said inner cavity, said first locking mechanism configured such that when retained in a retracted position by a retaining member, said locking mechanism enabl es free movement of said centralizer housing with respect to said wel l bore pipe and when said retaining member is removed and said first locking mechanism is in an enabled position, said first locking mechanism provides a frictional force between said w ellbore pipe and said centralizer housing that restricts axial movement of said centralizer housing w ith respect to said w ellbore pipe; removing said retaining member to attach said centralizer to said w ellbore pipe: moving axially said centralizer housing with respect to said w el lbore pipe: and engaging a second locking mechanism coupled with said inner cavity and configured such that when in an unlocked position, said second locking mechanism provides a second gripping force that restricts rotational movement of said centralizer housing with respect to said wellbore pipe.

CENTER-005 [00228] In one embodiment, the first locking mechanism moves to said enabled position without requiring an applied force.

[00229] In one embodiment, the first locking mechanism remains in said enabled position without requiring an appl ied force.

[00230] Although illustrative embodiments have been described in detail herein with reference to the accompanying drawings, variations to specific embodiments and details are encompassed by this disclosure. It is intended that the scope of embodiments descri bed herein be defined by claims and their equivalents. Furthermore, it is contemplated that a particular feature descri bed, either individually or as part of an embodiment, can be combined with other individually described features, or parts of other embodiments

[00231 ] All elements, parts and steps described herein are preferably included. It is to be understood that any of these elements, parts and steps may be replaced by other elements, parts and steps or deleted altogether as will be obvious to those skilled in the art.

100232] This writing discloses at least the following: A wellbore pipe centralizer including a substantially cylindrical outer body having a first inner diamter at each end thereof and a second inner diameter located intermediate of the ends, wherein the second inner diameter is greater than the first inner diameter, a spring comprising a helically wound wire having at least one coil and a first wire end and a second wire end, positioned substantially co-a\ially within the outer body and proximate the second diameter, the spring having a spring expanded position such that an inner diameter of the at least one coil of the spring is substantially equal to or greater than the first diameter, and having a spring released position such that the inner diameter CENTER-005 of the at least one coil would be smaller than the first diameter were the spring unrestrained and a retainer member having a first retainer position wherein it extends through an aperture in the outer body and has a leg portion abutting at least one of the first and second wire ends such that the spring is restrained in the spring expanded position and having a second retainer position wherein the leg portion is removed from abutment with the at least one of the first and second wire ends such that the spring may move to its spring released position.

CONCEPTS

This writing also presents at least the following concepts.

1 . A wellbore pipe centralizer comprising: a substantially cylindrical outer body having a first inner diameter at each end thereof and a second inner diameter located intermediate of the ends, wherein the second inner diameter is greater than the first inner diameter; a spring comprising a helical ly wound wire having at least one coil and a first wire end and a second wire end, positioned substantially co-axially with in the outer body and proximate the second diameter, the spring having a spring expanded position such that an inner diameter of the at least one coi l of the spring is substantially equal to or greater than the first diameter, and having a spring released position such that the inner diameter of the at least one coil would be smaller than the first diameter were the spring unrestrained; and a retainer member having a first retainer position wherein it extends through an aperture in the outer body and has a leg portion abutting at least one of the first and second wire ends such that the spring is restrained in the spring expanded position and having a second retainer position wherein the leg portion is removed from abutment with the at least one of the first and second wire ends such that the spring may move to its spring released position.

2. The wellbore pipe central izer of concept 1 wherein the outer body further includes at least one inner diameter taper located axial ly between the second inner diameter and at least one of the first inner diameters, and wherein the centralizer further comprises a slip spring, positioned substantially co-axial ly with in the outer body and proximate the spring, and having a sl ip spring expanded position such that an inner diameter of the sl ip spring is substantially equal to or greater than the first diameter, and having a sl ip spring released position such that the inner diameter of the slip spring would be smaller than the first diameter were the sl ip spring unrestrained.

3. The wellbore pipe centrahzer of Concept 2 wherein the slip spring comprises at least one circumferentially distributed pipe gripping edge, and a first slip wire end and a second slip wire end.

4. The wel lbore pipe centrahzer of Concept 3 wherein the pipe gripping edge is proximate an inner diameter of the sl ip spring.

5. The wel lbore pipe centrahzer of Concept 3 wherein the slip spring is restrained in the sl ip spring expanded position by one of the retainer and a second retainer.

6. The wel lbore pipe centrahzer of Concept 2 wherein the slip spring is movable between a first taper location and a second taper location when the slip spring is in the slip spring released position and where the first taper location inner diameter is greater than the second taper location inner diameter.

7. The wel lbore pipe centrahzer of Concept 3 wherein the slip spring comprises wire having a substantially rectangular cross-section.

8. The wel lbore pipe centrahzer of Concept 7 wherein the gripping edge comprises at least one corner edge of the wire.

9. The wellbore pipe centrahzer of Concept 3 wherein the slip spring comprises a circumferential body having at least one raised portion including the gripping edge thereon.

1 0. The wellbore pipe centrahzer of Concept 6 further comprising a first inner diameter taper and a first sl ip-spring movable therein, wherein the first slip spring is movable between an initial first taper location and an end ing first taper location when the first sl ip spring is in the sl ip spring released position and where the initial first taper location inner diameter is greater than the ending first taper location inner diameter, and a second inner diameter taper and a second slip spring movable therein, wherein the second slip spring is movable between an initial second taper location and an ending second taper location when the second slip spring is in the slip spring released position and where the initial second taper location inner diameter is greater than the ending second taper location inner diameter.

1 1 . A locking centralizer comprising: a housing with an inner cavity configured to slide over an outer surface of a tubular member, said housing comprising an outer surface for centering said tubular member within a borehole; a first locking mechanism coupled with said inner cavity and configured such that when in a disabled position, said first locking mechanism does not prevent axial movement of said housing with respect to said tubular member and when in an enabled position, said first locking mechanism provides a first gripping force that restricts axial movement of said housing with respect to said tubular member; and a second locking mechanism coupled with said inner cavity and engageable concurrently with said first locking mechanism that when in an enabled position, said second locking mechanism augments said first gripping force of said first locking mechanism and further restricts movement of said housing with respect to said tubular member.

12. The locking central izer of Concept 1 1 wherein said second locking mechanism provides a second gripping force that restricts axial movement of said housing with respect to said tubular member. 13. The locking mechanism of Concept 1 1 wherein said second locking mechanism provides a second gripping force that restricts rotational movement of said housing with respect to said tubular member.

14. The locking centralizer of Concept 1 1 wherein said second locking mechanism comprises at least one twisted square wire.

15. The locking centralizer of Concept 1 1 further comprising a lock retainer coupled with said housing and configured for securing said first locking mechanism and said second lock mechanism in disabled positions.

16. The locking centralizer of Concept 15 wherein said lock retainer is removable and configured for allowing enablement of said first locking mechanism and configured for allowing enablement of said second lock mechanism when removed from said housing.

17. The locking centralizer of Concept 1 1 wherein said inner cavity of said housing comprises a variable diameter surface that wedges said second locking mechanism against said outer surface of said tubular member.

18. The locking centralizer of Concept 17 wherein axial movement of the housing impinges the second locking mechanism axially against the first locking mechanism thereby further wedging the second locking mechanism against the outer surface of the tubular member.

19. A locking centralizer comprising: a cylindrical housing with a concaved inner surface configured to house a locking mechanism that is configured to slide over an outer surface of a tubular member, said cylindrical housing comprising an outer surface for centering said tubular member within a borehole; said a locking mechanism comprising: a first stage lock configured such that when in a first unlocked position, said first stage lock allows axial movement of said cylindrical housing with respect to said tubular member and when in a locked position, said first stage lock provides a first gripping force that restricts axial movement of said housing with respect to said tubular member; and a second stage lock configured such that when in a second locked position, said second stage lock provides a second gripping force that further prevent said axial movement of said housing with respect to said tubular member, said second gripping force also restricts movement of said locking centralizer with respect to said tubular member.

20. The locking centralizer of Concept 19 wherein said second stage lock restricts rotational movement of said locking centralizer with respect to said tubular member.

21 . The locking centralizer of Concept 19 wherein said second stage lock comprises one or more helical ridges that restrict said rotational movement of said locking centralizer with respect to said tubular member.

22. The locking centralizer of Concept 19 wherein said first stage lock comprises a helically wound flat wire spring with at least one coil.

23. A method for attaching a centralizer to a tubular member, said method comprising: placing a centralizer housing onto said tubular member, said centralizer housing comprising an inner cavity configured to slide over an outer surface of said tubular member, said housing comprising an outer surface for centering said tubular member within a borehole; accessing a first locking mechanism coupled with said inner cavity, said first locking mechanism configured such that when retained in a retracted position by a retaining member, said locking mechanism allows axial movement of said central izer housing with respect to said tubular member and when said retaining member is removed and said first locking mechanism is in an enabled position, said locking mechanism provides a gripping force that restricts axial movement of said housing with respect to said tubular member; and releasing said retaining member to attach said central izer to said tubular member.