WELL CELLAR EXCAVATING DEVICE AND METHOD

BACKGROUND OF THE INVENTION

1. Field of Invention

[0001] The present disclosure relates to excavating in a cellar circumscribing a wellhead. More specifically, the present disclosure relates to excavating a wellhead cellar with a segmented device that circumscribes the wellhead.

2. Description of Prior Art

[0002] Hydrocarbon producing wellbores extend subsurface and intersect subterranean formations where hydrocarbons are trapped. Some type of hardware is typically mounted at the opening of each wellbore during drilling, and over the remaining life of the wellbore. During the time the wellbore is being drilled, the wellhead assembly usually is made up of a wellhead housing mounted over conductor pipe, and with a blow-out prevented (“BOP”) mounted on an upper end of the wellhead housing. Also during one stage of drilling, conductor pipe is added which lines an upper portion of the wellbore. After drilling is complete, and prior to producing from the wellbore; the BOP is usually replaced with a production tree for controlling the flow of fluids produced from the wellbore.

[0003] A cellar is often formed around an opening of a wellbore, and that extends into the ground a few feet below the Earth’s surface. Wellhead cellars are sometimes used as a workspace for operations personnel to access valves and other fluids handling equipment associated with the wellhead assembly. Occasionally, cellars are also configured to capture and collect fluids leaking from wellhead equipment, or that has spilled around the wellhead. Without a cellar, the leaking/spilled fluids might otherwise contaminate the ground around the well. The types of leaking fluids that are collected generally include one or more of drilling fluid, oil, lubricants, or completion fluids. To ensure fluid is collected properly, a cellar is typically lined with sheet metal, fiberglass, or concrete. Because wellbore cellars circumscribe a portion of the associated wellbore, difficulties arise when excavating in an existing wellbore cellar, or when forming a new cellar around a wellbore during production.

SUMMARY OF THE INVENTION

[0004] Disclosed herein is an example of a system for excavating around a wellbore, which includes a selectively rotatable excavating unit that is driven by a motor. The excavating unit of this example includes an annular body having a cutting surface selectively disposed in cutting engagement with ground that circumscribes the wellbore, inserts disposed on the cutting surface, a bin removably disposed in a recess the body, a slot formed in the body that extends from the cutting surface to the recess, and a receptacle in the bin that selectively receives cuttings formed by contacting ground around the wellbore with the inserts. When the motor is in an operating mode, the excavating unit is rotating and excavating the cuttings from the ground. In an alternate embodiment, the receptacle receives the cuttings through an opening formed in a sidewall of the bin. In this alternate embodiment, a planar cover is set adjacent the opening when the bin is disposed in the recess, and the cover is urged adjacent the cover when the bin is removed from the recess to define a barrier to communication of cuttings through the opening. In an alternative to this embodiment, a ledge is formed at a location on an inner surface of the recess to be in interfering contact with the cover to space the cover away from the opening when the bin is disposed in the receptacle. In another embodiment, the motor is rotatingly engaged with the excavating unit with a belt. In another embodiment, the annular body is made up of angular segments that each extend along a portion of a circumference of the annular body, and optionally each segment includes a forward wall that is in a forward plane that intersects and is substantially parallel with an axis of the annular body, and a rearward wall that is in a rearward plane that intersects and is substantially parallel with the axis, and wherein the forward plane is oblique with the rearward plane. Further optionally, the angular segments are releasably coupled to one another to form the annular body. In another embodiment, the inserts are disposed rearward of an intersection of the slot and the cutting surface.

[0005] Another example of a system for excavating around a wellbore is described, and which includes a motor and an excavating unit. The excavating unit of this example is made up of an annular body that selectively rotates in response to a rotational force received by the motor, a cutting surface defined on an axial end of the body, inserts on the cutting surface that are in selective excavating contact with ground around the wellbore, a bin removeably disposed in the body, and a slot in the body that extends from the cutting surface to the bin, and which receives cuttings formed by the excavating contact of the inserts and the ground. In an alternate embodiment, the body includes curved segments that each form a circumferential portion of the body, and optionally each segment is attached to an adjacent segment by a coupling, and further optionally, each segment has a planar forward wall that attaches to a planar reward wall formed on the adjacent segment.

[0006] Also disclosed herein is an example method of excavating around a wellbore, which includes handling an excavating unit that is made up of an annular body, a cutting surface, a receptacle in the body, and a slot that extends from the cutting surface to the receptacle. The method of this example includes mounting the excavating unit around the wellbore so that the cutting surface is in contact with ground circumscribing the wellbore, excavating cuttings from the ground by rotating the body, and directing the cuttings into a receptacle disposed in the body. In an alternate method, excavating cuttings from the ground involves forming a new cellar around the wellbore or deepening an existing cellar that is around the wellbore. Another alternate method further includes removing the receptacle from the body, and emptying the cuttings from the receptacle, and optionally further includes blocking communication between the slot and the receptacle when the receptacle is removed from the body. In another alternative, the body has segments that each circumscribe a portion of the wellhead, and wherein mounting the excavating unit includes assembling the excavating unit by attaching the segments to one another. In another alternative, a wellhead assembly is coupled with the wellbore while the excavating unit is being mounted around the wellbore. In another alternative, the wellbore is a first wellbore and the excavating unit is removed from the first wellbore, and the excavating unit is then mounted around a second wellbore that is spaced away from the first wellbore, and ground from around the second wellbore is excavated with the excavating unit.

BRIEF DESCRIPTION OF DRAWINGS

[0007] Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:

[0008] Figure 1 is a side partial sectional view of an example of an excavating unit excavating in a wellbore cellar.

[0009] Figure 2 is a partially exploded perspective view of an example of the excavating unit of Figure 1

[0010] Figures 3A and 3B are side sectional schematic views of an example of excavating with the excavating unit of Figure 1.

[0011] While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF INVENTION

[0012] The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term “about” includes +/- 5% of a cited magnitude. In an embodiment, the term “substantially” includes +/- 5% of a cited magnitude, comparison, or description. In an embodiment, usage of the term “generally” includes +/- 10% of a cited magnitude.

[0013] It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.

[0014] Shown in a side partial sectional view in Figure 1 is an example of a cellar excavating system 10 excavating in a wellbore cellar 12. As shown, the wellbore cellar 12 extends into ground 14 that circumscribes a portion of a wellbore 15. Mounted above wellbore 15 is an example of a wellhead assembly 16, and the portion of wellbore 15 depicted is circumscribed by a conductor pipe 17 that depends downward from wellhead assembly 16. Included in the excavating system 10 is an annular excavating unit 18, which as described in more detail below is made up of segments 20i, 20 ₂ that each form an angular portion along a circumference of the excavating unit 18. When combined, segments 20i, 2O ₂ define a body 21; and as shown segments 20i, 2O ₂ join one another along an interface 22i, which follows a path parallel with an axis Ax of excavating body 18. An optional coupling 23 ₁ is shown mounted across interface 22 ₁ and for providing a coupling means for attaching segments 20 ₁ , 2O ₂ together.

[0015] Motors 24 _1,2 are shown above ground 14 and outside of wellbore cellar 12, and which respectively couple with excavating unit 18 by belts 26 _1,2 . Belts 26 _1,2 are elongate flexible members formed into a continuous loops, and with sufficient structural integrity to exert a force that causes rotation of excavating unit 18 within wellbore cellar 12. As illustrated by arrow A _R , excavating unit 18 is rotated within wellbore cellar 12 by forces generated by operation of motors 24 _1,2 and their coupling with the belts 26 _I,2 , which transfers the forces to the excavating unit 18. Alternate embodiments exist where a single motor 24 and single belt 26 are used for driving the excavating unit 18. The cellar bottom 28 is formed on a lowermost surface within wellbore cellar 12 and distal from wellhead assembly 16.

[0016] Shown in Figure 2 is a perspective partially exploded view of the excavating unit 18, and illustrating that the segments 201-3 making up the body 21 each extend roughly same angular distance around the circumference of unit 18; but embodiments exist where the particular segments 20 _1-3 each extend a different angle about axis Ac. As illustrated in Figure 2, each segment 20 _1-3 includes a housing 30i- ₃ having a recess 32 _I-3 ; each recess 32 _I-3 is open on an upper end, is closed on a lower end, and has sidewalls spanning between the upper and lower ends, and which extend along a portion of the axial length of each of the segments 2O _1-3 . In one embodiment, radial widths of each of the recesses 32 _I-3 is substantially the same along their respective azimuths and depths. In the example of Figure 2, for the purposes of illustration segment 2O ₃ is shown detached from segments 20 _I,2 . Also shown is a bin 34 ₃ shown having a semi-circular wedge-like configuration similar to segment 2O ₃ is spaced above segment 2O ₃ . In this example, each recess 32 _I-3 receives a bin 34 _I-3 that is selectively removable from within their respective recesses 32 _I-3 . Similar to the recesses 32 _I-3 , each of the bins 34 _I-3 is open on their respective upper axial ends, and closed on their lower ends; which defines receptacles 36 _1-3 within each of the bins 34 _I-3 . In Figure 2, bin 34 ₃ is shown outside of its recess 32 ₃ for purposes of illustration. As shown, bin 34 ₃ includes an inner wall 38 ₃ facing radially inward towards the conductor pipe 17 (when installed), and an outer wall 40 ₃ on a side radially spaced away from inner wall 38 ₃ . A planar rearward wall 42 ₃ spans between the inner and outer walls 38 ₃ , 40 ₃ and upward from the lower closed end. When bin 34 ₃ is set within recess 32 ₃ , rearward wall 42 ₃ is in a plane that intersects with axis Ac. A planar forward wall 44 ₃ spans upward from the lower closed end and between ends of the inner and outer walls 38 ₃ , 40 ₃ opposite from rearward wall 42 ₃ , forward wall 44 ₃ lies in a plane that also intersects axis Ac. As shown, forward wall 44 ₃ is arranged substantially oblique to rearward wall 42 ₃ .

[0017] In the example of Figure 2 an opening 46 ₃ is shown in a dashed outline, which is formed through forward wall 44 ₃ ; a cover 48 ₃ is shown set over opening 46 ₃ , and which blocks communication from within receptacle 36 ₃ past forward wall 44 ₃ through opening 46 ₃ . A retaining means 50 ₃ is shown coupled with cover 48 ₂ and also with forward wall 44 ₃ for retaining the cover 48 ₃ in the position over opening 46 ₃ . In one example, retaining means 50 ₃ is a resilient member, such as a spring, and in an example will deform under an applied force and allow sliding movement of cover 48 ₃ away from opening 46 ₃ . Still referring to Figure 2, a slot 52 ₃ is shown in dashed outline formed through the housing 30 ₃ of segment 2O ₃ . Slot 52 ₃ extends from a cutting surface 54 which is on a side of the excavating unit 18 opposite from the upper open ends of the recess 32 _I-3 and the bins 34 _I-3 - Also shown in dashed outline in on cutting surface is an insert 56 ₃ which provides an excavating function for cutting through the ground 14 by rotation R of the excavating unit 18.

[0018] Still referring to Figure 2, the exploded example illustrates that similar to the bin 34 ₃ , segment 2O ₃ includes a planar inner wall 58 ₃ which is curved and on a side of segment 2O ₃ facing radially inward towards conductor pipe 17. Radially outward from inner wall 58 ₃ is a planar outer wall 6O ₃ . Planar rearward and forward walls 62 ₃ , 64 ₃ extend upward from a lower wall of segment 2O ₃ and radially between opposing edges of inner wall 58 ₃ and outer wall 6O ₃ . When segment 2O ₃ is installed with excavating unit 18 each of the rearward and forward ends 62 ₃ , 64 ₃ are in planes that are parallel with and intersect axis Ax, and rearward and forward walls 62 ₃ , 64 ₃ are oblique with one another. Shown on rearward and forward walls 62 ₃ , 64 ₃ is an alternate embodiment of an attachment for coupling together adjacent segments 2O _1-3 and which is made up of lugs 66 ₃ shown as members projecting generally perpendicular from the rearward and forward walls 62 ₃ , 64 ₃ and having cylindrically shaped portions. Further optionally as shown in Figure 2, the body 21 may be made up axial segments as well as angular segments; where each axial segment extends along a portion of the axis Ax of excavating unit 18. An example of a radial interface 67 ₃ is illustrated indicating where axial segments of angular segment 2O ₃ are joined, to demonstrate an embodiment of angular segment 2O ₃ being made up of axial segments.

[0019] Referring now to Figures 3 A and 3B, shown in a side sectional view is a non-limiting example of the excavating unit 18 being rotated over the ground 14 to excavate within the wellbore cellar 12. More specifically, referring to Figure 3A, a portion of segment 20 ₁ is shown being rotated in a direction represented by arrow R _D . The rotation causes insert 56i to scrape along a surface of ground 14, the scraping interaction between insert 56i and ground 14 removes pieces of the ground to produce cuttings 68; which are shown being directed into receptacle 36i of bin 34i. As depicted in Figure 3 A, bin 34 ₁ set within recess 32i and cover 48 ₁ is spaced away from opening 46i and in a retracted configuration. In the example of Figure 3 A, a ledge 70i is shown that extends radially along a forward facing sidewall of recess 32i and is where an angular length of recess 32i transitions lower. The portion of bin 341 below the bottom of cover 481 is insertable into the portion of recess 32i below ledge 70i. However, in the illustrated embodiment, the dimensions of this lower portion are insufficient to accommodate the bin 341 with the cover 481, which results in cover 48i landing on ledge 70i when bin 34i inserts into recess 32i. Interference between ledge 70i and cover 48i urges cover 481 into the retracted configuration and away from opening 46i; which allows registration between slot 52i and opening 46i to allow communication of the cuttings 68 through body 21 and into bin 34i. Also noted is the configuration and placement of insert 56i on a downward side of where slot 52i intersects with cutting surface 54i. Positioning of insert 56i on the downward side in one example helps guide cuttings 68 into an opening of slot 52i and for easing their travel into the receptacle 361.

[0020] In the example of Figure 3B receptacle 34i is being removed from recess 32i for the emptying of the cuttings 68. In this example, at a point in time when an amount of cuttings 68 has entered the bin 34i to occupy a designated amount of space within receptacle 36i a force F is applied to the bin 34i and pull it from recess 32i. In this example, optional eyehooks 72i are provided with the bin 34i to provide a place where force F is applied. Also noted in the example of Figure 3B is that as the bin 34i is drawn from within the recess 32i, interfering contact between ledge 70i and cover 481 is removed so that the urging means 50i draws cover 481 back adjacent opening 461 to block the escape of the cuttings 68 through opening 461. After emptying the cuttings 68 from within bin 38i, bin 34i is placed back into recess 32i for further excavation of cellar.

[0021] Referring back to Figure 1, in one non-limiting example of operation, segments 20i- ₃ of excavating unit 18 are handled and positioned proximate the wellhead assembly 16. As noted above, the configuration of the excavating unit 18 with the multiple segments 201-3 allows for assembly of the excavating unit 18 onsite and at a wellhead assembly 16. One or both motors 261,2 are coupled with the assembled excavating unit 18 and rotation is imparted upon unit 18 to begin excavating cuttings 68 (Figure 3A) from ground 14 so that wellbore cellar 12 is either deepened or newly formed. As noted above, a designated amount of cuttings 68 occupy the receptacle 36i- ₃ the associated bin 34I- ₃ is temporarily removed and the cuttings 68 emptied therefrom. Further in this example, after placing the emptied bin 34I- ₃ back into its recess 32I- ₃ , excavation within wellbore cellar 12 resumes. At a time when a wellbore cellar 12 of a designated depth is achieved, the cellar excavating system 10 is disassembled and removed; and in one example taken to a second wellhead assembly 16A which is spaced away from wellhead assembly 16. In this example, cellar excavating system 10 is reassembled as for deepening or creating a new cellar adjacent wellhead assembly 16A.

[0022] The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.