A STATOR IN A PROGRESSING CAVITY PUMP

TECHNICAL FIELD

An apparatus and a method for use in positioning a rotor within a stator in a progressing cavity pump.

BACKGROUND OF THE INVENTION

A progressing cavity pump is a rotary pump which is commonly used, amongst other applications, for pumping fluids from a subterranean well.

A progressing cavity pump includes a rotor and a stator. The rotor rotates within the stator. The rotor is typically constructed of metal and has one or more helical lobes on its outer surface. The stator is typically constructed as a tubular metal conduit which is commonly lined with an elastomeric liner. The stator has two or more helical lobes on its inner surface which are defined by the tubular metal conduit and/or by the elastomeric liner. The stator typically has one more helical lobe than the rotor.

During use of a progressing cavity pump, the rotor is received within the stator so that cavities are provided between the rotor and the stator due to the interfacing of the helical lobes on the rotor and the stator. The pump is typically operated by rotating the rotor. Rotation of the rotor causes the cavities to "progress" from one end of the pump to the other end of the pump so that fluids contained in the cavities are moved along the length of the pump. The optimum operation of a progressing cavity pump requires that the rotor be positioned within the stator at an appropriate longitudinal rotor position relative to the stator.

During use of a progressing cavity pump to pump fluids from a subterranean well, the pump is typically positioned in the wellbore adjacent to the fluids to be pumped and the rotor is typically rotated either by a motor located in the wellbore or by a rod string which is connected to the rotor and which is driven by a motor at the surface of the well.

A progressing cavity pump may be deployed in a well by several different methods. In some cases, the stator may be connected to a lower end of a tubing string, the tubing string may be inserted in the well, the rotor may be connected to a lower end of a rod string, and the rod string may be lowered into the tubing string in order to insert the rotor within the stator. In such cases, a challenge exists in ensuring that the rod string is lowered into the well so that the rotor is positioned within the stator at an appropriate longitudinal rotor position relative to the stator.

In other cases, the rotor and the stator may be inserted in the well together as a unit and the stator may be anchored to a casing string or a tubing string at an appropriate depth in the wellbore. In some such cases, after the pump is installed in the well, the rotor must be positioned relative to the stator before the pump can be used. In such cases, a challenge once again exists in ensuring that the rotor is positioned at the appropriate longitudinal rotor position relative to the stator.

During use of a progressing cavity pump to pump fluids from a subterranean well, it may become necessary to remove the rotor from within the stator temporarily in order to perform servicing operations in the well, and then to return the rotor to a position within the stator when the servicing operations are completed. It may also be necessary in some circumstances to "adjust" the longitudinal position of the rotor relative to the stator. It is desirable for these operations to be performed without removing the stator from the well. In these circumstances, a challenge once again exists in ensuring that the rotor is positioned at the appropriate longitudinal rotor position relative to the stator following servicing operations or when the longitudinal rotor position relative to the stator is adjusted.

Positioning the rotor within the stator may require that the rotor be moved longitudinally relative to the stator in a proximal direction and/or in a distal direction until the appropriate longitudinal rotor position is achieved.

Positioning the rotor within the stator may be assisted by a "tagging device" which is associated with the pump. A tagging device is typically comprised of a structure or apparatus which limits the longitudinal movement of the rotor relative to the stator in the distal direction to a particular longitudinal position relative to the stator and/or which provides a tagging indication when the rotor is at a particular longitudinal position relative to the stator. The tagging indication may be comprised of a sudden increase in the reaction force which is exerted on the rod string as the rod string is moved through the wellbore, may be comprised of a decrease in the perceived weight of the rod string, or may be comprised of some other form of indication.

Conventionally, a tagging device may be comprised of a tubular structure connected to the distal end of the stator which includes a "tag bar ^' ' extending across its bore. During longitudinal movement of the rotor in the distal direction, the rotor may pass through the bottom of the stator until the distal end of the rotor engages the tag bar and thus provides a tagging indication which can be sensed at the surface of the well. The rotor is then typically moved in the proximal direction in order to position the rotor at a desired longitudinal rotor position relative to the stator. Unfortunately, the tag bar provides an obstruction at the distal end of the progressing cavity pump which can interfere with fluid flow into the pump, can collect debris, and which renders it difficult or impossible to lower tools through and below the pump. One variation of the conventional tag bar form of tagging device involves including the tag bar (or similar structure) in a rotatable platform so that the rotor may remain engaged with the tagging device during use of the pump, with the result that the tagging indication directly indicates the appropriate longitudinal rotor position relative to the stator and further longitudinal manipulation of the rotor is not required in order to position the rotor. Examples of this variation of the conventional tag bar form of tagging device are described in U.S. Patent No. 6,338,388 (Winkler) and Canadian Patent Application No. 2,433,627 (Jack et al).

Another variation of the conventional tag bar form of tagging device involves providing a "tag shoulder" at a proximal end of the stator and a "stop" at a proximal end of the rotor which engages the tag shoulder to provide the tagging indication. The rotor may then be moved in the proximal direction in order to position the rotor at a desired longitudinal rotor position relative to the stator. An advantage of this variation of the conventional tag bar form of tagging device is that the obstruction provided by the presence of a tag bar at the bottom of the stator is eliminated. Examples of this variation of the conventional tag bar form of tagging device are described in U.S. Patent No. 7,201 ,222 (Kanady et al) and U.S. Patent Application Publication No. US 2009/0136371 Al (Gerling).

There remains a need for other forms of tagging devices and for methods for use in positioning a rotor within a stator of a progressing cavity pump. SUMMARY OF THE INVENTION

References in this document to orientations, to operating parameters, to ranges, to lower limits of ranges, and to upper limits of ranges are not intended to provide strict boundaries for the scope of the invention, but should be construed to mean "approximately" or ^• 'about" or "substantially", within the scope of the teachings of this document, unless expressly stated otherwise. As used herein, "proximal" means located relatively toward an intended

"uphole" end, "upper" end and/or "surface" end of a wellbore or of an apparatus positioned in the wellbore as a point of origin.

As used herein, "distal" means located relatively away from an intended "uphole" end, "upper" end and/or "surface" end of a wellbore or of an apparatus positioned in the wellbore as a point of origin.

As used herein, "fluid" means any fluid which may be pumped using a progressing cavity pump.

The present invention is directed at an apparatus for use in positioning a rotor within a stator of a progressing cavity pump. In some embodiments, the invention may be more specifically directed at a tagging device for use in positioning a rotor within a stator of a progressing cavity pump. In some embodiments, the invention may be directed at a tagging device assembly.

The present invention is also directed at a method for use in positioning a rotor within a stator of a progressing cavity pump. In some embodiments, the method of the invention may be performed using the apparatus of the invention.

In an exemplary apparatus aspect, the invention is a tagging device assembly for a progressing cavity pump of the type comprising a rotor and a stator, wherein the progressing cavity pump has a longitudinal pump axis and wherein the rotor may be moved longitudinally relative to the stator in a proximal direction and in a distal direction in order to position the rotor within the stator, the tagging device assembly comprising: (a) a tagging member associated with the rotor;

(b) a tagging receptacle associated with the stator, for receiving the tagging member; and a tagging latch device, for releasably latching the tagging member with the tagging receptacle when the tagging member is received within the tagging receptacle in order to inhibit relative longitudinal movement between the rotor and the stator.

The tagging latch device may be comprised of any structure, device or apparatus suitable for releasably latching the tagging member with the tagging receptacle.

The tagging latch device may be actuated in any suitable manner in order to latch and/or release the latching of the tagging member with the tagging receptacle. In some embodiments, the tagging latch device may be actuated by manipulating the rotor. In some embodiments, the tagging latch device may be actuated by manipulating the rotor in the proximal direction and/or manipulating the rotor in the distal direction. In some embodiments, the tagging latch device may be actuated by manipulating the rotor in a rotating direction.

In some embodiments, the tagging member may be comprised of a tagging member latch component. In some embodiments, the tagging receptacle may be comprised of a tagging receptacle latch component. In some embodiments, the tagging latch device may be comprised of the tagging member latch component and the tagging receptacle latch component.

The tagging member latch component and the tagging receptacle latch component may be comprised of any structures, devices or apparatus which are capable of cooperating with each other in order to releasably latch the tagging member with the tagging receptacle.

In some embodiments, the tagging latch device may be comprised of at least one radially movable key and at least one recess for receiving the at least one key. In some embodiments, one of the tagging member latch component and the tagging receptacle latch component may be comprised of the at least one key and the other of the tagging member latch component and the tagging receptacle latch component may be comprised of the at least one recess. In some embodiments, the tagging member latch component may be comprised of the at least one key and the tagging receptacle latch component may be comprised of the at least one recess.

In some embodiments, the tagging latch device may be further comprised of a biasing mechanism for radially biasing the at least one key toward engagement with the at least one recess. The biasing mechanism may be comprised of any structure, device or apparatus which is capable of providing the biasing function. In some embodiments, the biasing mechanism may be comprised of at least one spring.

In some embodiments, the tagging receptacle may be further comprised of a tagging receptacle bore for receiving the tagging member. In some embodiments, the tagging receptacle latch component may be comprised of a biasing mechanism for radially biasing the at least one key to protrude into the tagging receptacle bore.

In some embodiments, the tagging device assembly may be further comprised of a release mechanism for releasing the latching of the tagging member with the tagging receptacle. The release mechanism may be comprised of any structure, device or apparatus which is suitable for releasing the latching of the tagging member with the tagging receptacle.

In some embodiments, the release mechanism may be comprised of a shape or contour on the at least one key and/or on the at least one recess. In some embodiments, the release mechanism may be comprised of a sloped shoulder on the at least one key and/or on the at least one recess.

In some embodiments, the at least one key may have a proximal key end and a distal key end, the at least one recess may have a proximal recess end and a distal recess end, at least one of the proximal key end and the proximal recess end may be comprised of a sloped shoulder for permitting the at least one key to move in the proximal direction relative to the at least one recess in response to a latching release force exerted on the rotor in the proximal direction, and the release mechanism may be comprised of the sloped shoulder. In some embodiments, the tagging device assembly may be further comprised of a no-go device for limiting the longitudinal movement of the rotor in the distal direction. The no-go device may be comprised of any structure, device or apparatus which is suitable for performing the function of the no-go device.

In some embodiments, the no-go device may be comprised of a no-go shoulder and a no-go surface for engaging the no-go shoulder. In some embodiments, the no-go device may be associated with the tagging member and/or with the tagging receptacle. In some embodiments, the tagging receptacle may be further comprised of a no-go shoulder and the tagging member may be further comprised of a no-go surface.

In some embodiments, the tagging device assembly may be further comprised of a fluid bypass for allowing a fluid to pass through the tagging receptacle when the tagging member is received in the tagging receptacle. The fluid bypass may be comprised of one or more passages in the tagging member and/or in the tagging receptacle. In some embodiments, the fluid bypass may be comprised of one or more fluid bypass passages in the tagging receptacle.

In some embodiments, the tagging device assembly may be further comprised of one or more fluid release ports for allowing a fluid to pass from an interior of the tagging device assembly to an exterior of the tagging device assembly. In some embodiments, the one or more release ports may be located proximal to the tagging latch device. In some embodiments, the one or more fluid release ports may be defined by the tagging receptacle. In some embodiments, the one or more fluid release ports may be comprised of fluid release passages which are angled relative to the longitudinal pump axis. In some embodiments, the one or more fluid release ports may be comprised of fluid release passages which are angled in the proximal direction from the interior of the tagging device assembly to the exterior of the tagging device assembly. In some embodiments which are comprised of one or more fluid release ports, the tagging device assembly may be further comprised of plugs for plugging the one or more fluid release ports when the fluid release ports are not required. In some embodiments, the plugs may be threaded plugs which are configured to engage with threaded bores in the one or more fluid release ports. The tagging device assembly may be configured to be associated with any portions, sections or areas of the rotor and the stator which enable the tagging device assembly to perform a tagging function. In some embodiments, the tagging device assembly may be configured to be associated with a proximal end of the rotor and a proximal end of the stator.

In some embodiments, the tagging device assembly may be configured to be associated with a distal end of the rotor and a distal end of the stator.

The tagging member may be associated with the rotor in any suitable manner. As non-limiting examples, the tagging member may be connected with the rotor directly or indirectly by a threaded connection, by welding, and/or in some other manner, or the tagging member may be integrally formed with the rotor.

The tagging receptacle may be associated with the stator in any suitable manner. As non-limiting examples, the tagging receptacle may be connected with the stator directly or indirectly by a threaded connection, by welding, and/or in some other manner, or the tagging receptacle may be integrally formed with the stator.

In some embodiments, the tagging member may be connected with the distal end of the rotor directly or indirectly with a rotor to rod coupler. In some embodiments, the tagging receptacle may be connected with the distal end of the stator directly or indirectly with a tubing collar.

In embodiments in which the tagging latch device is comprised of at least one key and at least one recess, the tagging latch device may be comprised of a single key and a single recess, a plurality of keys and a plurality of recesses, a plurality of keys and a single recess, or a single key and a plurality of recesses.

In embodiments in which the tagging latch device is comprised of at least one key and at least one recess, the at least one key may have any shape and/or configuration which is suitable for enabling the key and recess to perform the releasable latching function.

In some embodiments, the at least one key may be generally circular in plan view and generally cylindrical in shape. In such embodiments, the at least one key may have a shoulder around its periphery. In some such embodiments, the shoulder may be a substantially ninety degree shoulder. In some such embodiments, the shoulder may be a sloped shoulder. In some such embodiments, a portion of the shoulder may be a substantially ninety degree shoulder and a portion of the shoulder may be a sloped shoulder. In some such embodiments in which the release mechanism is comprised of a sloped shoulder, the proximal key end may be comprised of a sloped shoulder. In some such embodiments, the distal key end may be comprised of a sloped shoulder.

In some embodiments, the at least one key may be generally rectangular in plan view and generally prism shaped. In such embodiments, the at least one key may have a shoulder around its periphery. In some such embodiments, the shoulder may be a substantially ninety degree shoulder. In some such embodiments, the shoulder may be a sloped shoulder. In some such embodiments, a portion of the shoulder may be a substantially ninety degree shoulder and a portion of the shoulder may be a sloped shoulder. In some such embodiments in which the release mechanism is comprised of a sloped shoulder, the proximal key end may be comprised of a sloped shoulder. In some such embodiments, the distal key end may be comprised of a sloped shoulder. In some such embodiments, the at least one key may be stepped in side view so that the at least one key defines one or more major protruding sections and one or more minor protruding sections. In some embodiments, only the one or more major protruding sections may be configured to be received in the at least one recess.

In embodiments in which the tagging latch device is comprised of at least one key and at least one recess, the at least one recess may have any shape and/or configuration which is compatible with the shape and configuration of the at least one key and which is suitable for enabling the key and recess to perform the releasable latching function.

In some embodiments, the at least one recess may be comprised of at least one slot. In some embodiments, the at least one recess may be comprised of at least one groove. In some embodiments, the at least one recess may be comprised of at least one continuous circumferential groove. In some embodiments, the at least one recess may be comprised of a single continuous circumferential groove.

In some embodiments, the tagging member may be comprised of an outer tagging member surface, the tagging member may have a tagging member circumference, the at least one recess may be comprised of at least one groove defined by the outer tagging member surface, and the at least one groove may extend around the entire tagging member circumference.

In some embodiments, the at least one key may be a plurality of keys spaced circumferentially around the tagging receptacle bore, the at least one recess may be a single groove extending around the entire tagging member circumference, and the tagging latching device may be configured so that the plurality of keys are received in the single groove when the tagging member is latched with the tagging receptacle.

The at least one key may be positioned in the tagging receptacle in any suitable manner. In some embodiments, the tagging receptacle may be comprised of at least one key cavity for retaining the at least one key and the at least one key may be retained in the at least one key cavity. In some embodiments in which the at least one key is a plurality of keys, the tagging receptacle may be comprised of a plurality of key cavities and one of the plurality of keys may be retained in each of the key cavities. In some such embodiments, the biasing mechanism may be comprised of a plurality of springs and at least one of the plurality of springs may be contained in each of the key cavities in order to bias the plurality of keys to protrude into the tagging receptacle bore.

In an exemplary method aspect, the invention is a method for positioning the rotor within the stator in a progressing cavity pump of the type comprising a rotor and a stator, wherein the progressing cavity pump has a longitudinal pump axis and wherein the rotor may be moved longitudinally relative to the stator in a proximal direction and in a distal direction, the method comprising:

(a) providing a tagging member, wherein the tagging member is associated with the rotor;

(b) providing a tagging receptacle for receiving the tagging member, wherein the tagging receptacle is associated with the stator;

(c) providing a tagging latch device, for releasably latching the tagging member with the tagging receptacle when the tagging member is received within the tagging receptacle in order to inhibit relative longitudinal movement between the rotor and the stator; (d) moving the rotor in the distal direction in order to receive the tagging member within the tagging receptacle and releasably latch the tagging member with the tagging receptacle;

(e) exerting a tagging testing force on the rotor in the proximal direction in order to confirm that the tagging member is releasably latched with the tagging receptacle;

(f) exerting a latching release force on the rotor in the proximal direction in order to release the latching of the tagging member with the tagging receptacle; and

(g) moving the rotor in the proximal direction in order to position the rotor within the stator at a desired longitudinal rotor position relative to the stator.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a longitudinal section assembly drawing of an exemplary embodiment of a tagging device assembly according to the invention and of components of a progressing cavity pump which are associated with the tagging device assembly.

Figure 2 is a longitudinal section assembly drawing of the tagging device assembly depicted in Figure 1 , showing the tagging member, the tagging receptacle and the tagging latch device in isolation.

Figure 3 is a schematic longitudinal section drawing of an alternate embodiment of a tagging receptacle within the scope of the invention, in which the tagging receptacle is comprised of a fluid bypass for allowing a fluid to pass through the tagging receptacle when the tagging member is received within the tagging receptacle.

Figure 4 is a schematic longitudinal section drawing of an alternate embodiment of a tagging receptacle within the scope of the invention, in which the tagging receptacle has been lengthened to accommodate the use of tongs with the tagging assembly, and in which the tagging receptacle includes a plurality of fluid release ports for allowing a fluid to pass from an interior of the tagging device assembly to the exterior of the tagging device assembly. DETAILED DESCRIPTION

The present invention is directed at an apparatus and at a method for use in positioning a rotor within a stator in a progressing cavity pump. Referring to Figures 1 -2, an exemplar}' embodiment is depicted of a tagging device assembly (20) according to the apparatus of the invention.

In the exemplary embodiment, the tagging device assembly (20) is associated with a progressing cavity pump (22). More particularly, the progressing cavity pump (22) is comprised of a rotor (24) and a stator (26).

In the exemplary embodiment, the stator (26) is comprised of a tagging housing (28). The tagging housing (28) is comprised of a tubular structure which provides a distal extension of the stator (26) below the helical lobes (not shown) of the stator (26). A function of the tagging housing (28) is to house the rotor (24) during positioning of the rotor (24) within the stator (26). The tagging housing (28) may be a connectable component of the stator (26) or may be integrally formed with the stator (26).

The progressing cavity pump (22) has a longitudinal pump axis (30). In Figures 1-2, the tagging device assembly (20) and the progressing cavity pump (22) are depicted as they would be if they were deployed in a wellbore (not shown).

When deployed in a wellbore, the stator (26) is typically connected to a distal end of a tubing string (not shown). The tubing string typically extends through the interior of a casing string (not shown) to a proximal end (i.e., surface end) of the wellbore. When deployed in a wellbore, the rotor (24) is typically connected to a distal end of a rod string (not shown). The rod string typically extends through the interior of the tubing string to the proximal end of the wellbore. The rotor (24) and the rod string may be moved longitudinally relative to the stator (26) in a proximal direction and in a distal direction in order to position the rotor (24) within the stator (26). The tagging device assembly (20) is comprised of a tagging member (40), a tagging receptacle (42) and a tagging latch device (44).

In the exemplary embodiment, the tagging member (40) is threadably connected with a distal end (50) of the rotor (24) with a rotor to rod coupler (52) which in turn is welded to the distal end (50) of the rotor (24).

In the exemplary embodiment, the tagging receptacle (42) is threadably connected with a distal end (54) of the tagging housing (28) with a tubing collar (56). The tagging receptacle (42) is comprised of a tagging receptacle bore (60) for receiving the tagging member (40). In the exemplary embodiment, the tagging receptacle bore (60) is generally circular and extends from a proximal end (62) of the tagging receptacle (42) to a distal end (64) of the tagging receptacle (42), thereby providing a passage through the tagging receptacle (42).

In the exemplary embodiment, the tagging receptacle (42) is further comprised of a sloped no-go shoulder (66) which extends into the tagging receptacle bore (60) at a location between the ends (62, 64) of the tagging receptacle (42). The portion of the tagging receptacle bore (60) which is proximal to the no-go shoulder (66) is a tagging member receiving section (68) of the tagging receptacle bore (60). The portion of the tagging receptacle bore (60) which is distal to the no-go shoulder (66) is a no-go section (70) of the tagging receptacle bore (60).

In the exemplary embodiment, the tagging receptacle (42) is further comprised of a tagging receptacle latch component (80). Referring to Figures 1 -2, in the exemplary embodiment the tagging receptacle latch component (80) is comprised of three radially movable keys (82) which are retained in three key cavities (84) spaced circumferentially around the tagging receptacle bore (60). The keys (82) are radially biased to protrude into the tagging receptacle bore (60) by a biasing mechanism. In the exemplary embodiment, the biasing mechanism is comprised of three springs (86), one of which is contained each of the three key cavities (84). The keys (82) and the springs (86) are maintained in the key cavities (84) with a key retaining sleeve (88) which is threadably connected with the exterior of the tagging receptacle (42). The keys (82) are prevented from passing completely into the tagging receptacle bore (60) by key retaining flanges (90) which support the keys (82) in the key cavities (84).

The tagging member (40) is sized and configured to fit within the tagging receptacle bore (60). In the exemplary embodiment, the tagging member (40) is therefore generally cylindrical in shape between a proximal end (96) of the tagging member (40) and a distal end (98) of the tagging member (40), and the tagging member (40) has an outer tagging member surface ( 100) and a tagging member circumference (102) which are generally complementary to the tagging receptacle bore (60).

In the exemplary embodiment, the tagging member (40) is further comprised of a sloped no-go surface (104) which is located at the distal end (98) of the tagging member (40). The no-go surface (104) is configured to engage the no-go shoulder (66) on the tagging receptacle (42) when the tagging member (40) is received fully in the tagging member receiving section (68) of the tagging receptacle (42). In the exemplary embodiment, the no-go surface ( 104) on the tagging member (40) also assists in guiding the tagging member (40) through the stator (26) and into the tagging receptacle bore (60) as the tagging member (40) is moved in the distal direction.

In the exemplary embodiment, the tagging member (40) is further comprised of a tagging member latch component (1 10), which is comprised of at least one recess for receiving the keys (82). Referring to Figures 1-2, in the exemplary embodiment the at least one recess is comprised of a single continuous circumferential groove ( 1 12) which is defined by the outer tagging member surface (100) and which extends around the entire tagging member circumference (102).

The tagging receptacle latch component (80) and the tagging member latch component (1 10) cooperate with each other to releasably latch the tagging member (40) with the tagging receptacle (42). The tagging receptacle latch component (80) and the tagging member latch component (1 10) are therefore complementary to and compatible with each other. Referring to Figures 1 -2, in the exemplary embodiment the three keys (82) are substantially identical to each other. Each of the keys (82) is generally rectangular in plan view and is generally prism shaped. Each of the keys (82) has a proximal key end (120), a distal key end (122), and a shoulder (124) around its periphery. The portion of the shoulder (124) at the proximal key end (120) is a sloped shoulder. The portion of the shoulder (124) at the distal key end (122) is also a sloped shoulder. The portions of the shoulder (124) along the sides of each key between the proximal key end (120) and the distal key end (122) are substantially ninety degree shoulders.

In the exemplary embodiment, each of the keys (82) defines a major protruding section (126) and a minor protruding section (128). In the exemplary embodiment, the major protruding section (126) is at the proximal key end (120) and the minor protruding section (128) is at the distal key end (122).

In the exemplary embodiment, the three keys (82) are located at the same longitudinal position between the proximal end (62) of the tagging receptacle (42) and the distal end (64) of the tagging receptacle (42).

In the exemplary embodiment, the groove (1 12) is shaped and configured to receive simultaneously the major protruding section (126) of each of the keys (82) when the tagging member (40) is received within the tagging receptacle (42) and the keys (82) are longitudinally aligned with the groove (1 12).

In the exemplary embodiment, the groove (1 12) has a proximal recess end ( 136) and a distal recess end (138). In the exemplary embodiment, the groove (1 12) has a shoulder (140) at the proximal recess end (136) and a shoulder (142) at the distal recess end (138). The shoulder (140) at the proximal recess end (136) is a sloped shoulder. The shoulder ( 142) at the distal recess end (138) is also a sloped shoulder.

In the exemplary embodiment, the tagging device assembly (20) is further comprised of a release mechanism (150) for releasing the latching of the tagging member (40) with the tagging receptacle (42). In the exemplary embodiment, the release mechanism (150) is comprised of the sloped shoulder (124) at the proximal key end (120) of each of the keys (82) and/or is comprised of the sloped shoulder (140) at the proximal recess end (136) of the groove (1 12). Either or both of these sloped shoulders (124, 140) permit the keys (82) to move in the proximal direction relative to the groove (1 12) in response to a latching release force which may be exerted on the rotor (24) in the proximal direction.

In the exemplary embodiment, the magnitude of the latching release force is dependent upon the size and configuration of the groove (1 12), the size and configuration of the keys (82), the angle of the sloped shoulder (124) at the proximal key end (120) of the keys (82), the angle of the sloped shoulder (140) at the proximal recess end (136) of the groove (1 12), and the biasing force provided by the springs (86).

In the exemplary embodiment, the tagging device assembly (20) may be further comprised of a fluid bypass (not shown in Figures 1 -2) for allowing a fluid (not shown) to pass through the tagging receptacle (42) when the tagging member (40) is received in the tagging receptacle (42).

Referring to Figure 3, a schematic depiction is provided of an alternate embodiment of a tagging receptacle (42) which includes a fluid bypass comprising a plurality of fluid bypass passages ( 160) extending through the tagging receptacle (42), wherein the fluid bypass passages (160) are spaced circumferentially around the tagging receptacle bore (60) between the key cavities (84). Alternatively or additionally, in the exemplary embodiment, the tagging device assembly (20) may be further comprised of one or more fluid release ports (not shown in Figures 1-2) for allowing a fluid (not shown) to pass from the tagging member receiving section (68) of the tagging receptacle bore (60) to the exterior of the tagging device assembly (20).

Referring to Figure 4, a schematic depiction is provided of an alternate embodiment of a tagging receptacle (42) which includes a plurality of fluid release ports comprising three fluid release passages (166), wherein the fluid release passages (166) are longitudinally spaced from and aligned with the key cavities (84). As depicted in Figure 4, the fluid release passages (166) are angled about sixty degrees in the proximal direction from the tagging receptacle bore (60) to the exterior of the tagging receptacle (42).

As depicted in Figure 4, the diameter or cross-sectional area of the fluid release passages (166) increases toward the exterior of the tagging receptacle (42). As depicted in Figure 4, the fluid release passages ( 166) are provided with threaded bores (168) toward the exterior of the tagging receptacle (42) so that the fluid release passages (166) may be plugged with threaded plugs (not shown) if the fluid release passages (166) are not required. Referring again to Figure 4, the alternate embodiment of the tagging receptacle

(42) is longer than the tagging receptacles (42) depicted in Figures 1 -3. In particular, the tagging receptacle (42) depicted in Figure 4 is extended on both sides of the tagging receptacle latch component (80) in comparison with the tagging receptacles (42) depicted in Figures 1 -3 in order to accommodate the use of tongs (not shown) such as tubing power tongs on the tagging receptacle (42).

In some embodiments, the method of the invention may be performed using the apparatus of the invention. In some embodiments, the method of the invention may be performed using one of the exemplary embodiments of the apparatus of the invention which are depicted in Figures 1 -4.

An exemplary embodiment of the method of the invention is now described. In the exemplary embodiment of the method of the invention, the method is performed using the exemplary embodiment of the apparatus of the invention which is depicted in Figures 1 -2.

In the exemplary embodiment of the method of the invention, the tagging member (40) is connected with the distal end (50) of the rotor (24) and the tagging receptacle (42) is connected with the distal end (54) of the tagging housing (28) of the stator (26). The rotor (24) and the stator (26) are components of a progressing cavity pump (22).

A tubing string is deployed in a wellbore. The stator (26), with the tagging receptacle (42) at its distal end, is connected with the tubing string at or near the distal end of the tubing string. The stator (26) may be connected with the tubing string before the tubing string is deployed in the wellbore or after the tubing string is deployed in the wellbore. The stator (26) is positioned at a desired longitudinal position within the wellbore. A rod string is deployed in the wellbore. The rotor (24), with the tagging member at its distal end, is connected with the distal end of the rod string. The rotor (24) and the rod string may be deployed in the wellbore with the stator (26) or may be deployed in the wellbore after the tubing string and the stator (26) are deployed in the wellbore.

The method of the invention may be performed during installation of the progressing cavity pump (22) for the purpose of positioning the rotor (24) within the stator (26), or may be performed after servicing of the well for the purpose of repositioning the rotor (24) within the stator (26).

The rotor (24) may be moved longitudinally relative to the stator (26) in a proximal direction (toward the ground surface) and in a distal direction (away from the ground surface) in order to position the rotor (24) within the stator (26).

A goal of the method of the invention is to position the rotor (24) at a desired longitudinal rotor position relative to the stator (26). In the performance of the method of the invention, the desired longitudinal rotor position may be a longitudinal rotor position which will enable optimum operation of the progressing cavity pump (22), or may be some other longitudinal rotor position.

The rotor (24) is moved in the distal direction by manipulating the rod string in order to receive the tagging member (40) within the tagging receptacle (42) so that the tagging latch device (44) releasably latches the tagging member (40) with the tagging receptacle (42). In the exemplary embodiment, the tagging latch device (44) releasably latches the tagging member (40) with the tagging receptacle (42) when the keys (82) in the tagging receptacle (42) are longitudinally aligned with the groove (1 12) in the tagging member (40).

In the exemplary embodiment, the rotor (24) is prevented from moving too far in the distal direction by the no-go shoulder (66) on the tagging receptacle (42) and the no-go surface ( 104) on the tagging member (40), which together provide a no-go device which limits the longitudinal movement of the rotor (24) relative to the stator (26) in the distal direction.

The latching of the tagging member (40) with the tagging receptacle (42) may provide a tagging indication which may be sensed in the manipulation of the rod string. The tagging indication may be comprised of a sudden increase in the reaction force which is exerted on the rod string as a result of the latching, may be comprised of a sudden decrease in the perceived weight of the rod string as a result of the latching, or may be comprised of some other form of indication.

The latching of the tagging member (40) with the tagging receptacle (42) represents a particular longitudinal position of the rotor (24) relative to the stator (26) which is known due to the configuration of the progressing cavity pump (22) and the tagging device assembly (20). As a result, once the latching of the tagging member (40) with the tagging receptacle (42) has been achieved, the rotor (24) may be moved in the proximal direction by a known distance in order to position the rotor (24) at the desired longitudinal rotor position relative to the stator (26).

In the exemplary embodiment, the latching of the tagging member (40) with the tagging receptacle (42) may be confirmed by exerting a tagging testing force on the rod string and the rotor (24) in the proximal direction. In the exemplary embodiment, the tagging testing force is a force which can be resisted by the tagging latch device (44) because of the configuration of the components of the tagging latch device (44) without releasing the latching of the tagging member (40) with the tagging receptacle (42).

In the exemplary embodiment, once the latching of the tagging member (40) with the tagging receptacle (42) has been confirmed, a latching release force may be exerted on the rod string and the rotor (24) in the proximal direction in order to release the latching of the tagging member (40) with the tagging receptacle (42). In the exemplary embodiment, the latching release force is a force which will allow the keys (82) to move in the proximal direction relative to the groove ( 1 12) because of the sloped shoulder ( 124) at the proximal key ends (120) and/or the sloped shoulder ( 140) at the proximal recess end ( 136) and thereby release the latching of the tagging member (40) relative to the tagging receptacle (42). Once the latching of the tagging member (40) with the tagging receptacle (42) has been released, the rotor (24) may be moved in the proximal direction in order to position the rotor (24) at the desired longitudinal rotor position relative to the stator (26). The rotor (24) is moved a known distance having regard to the configuration of the progressing cavity pump (22) and the tagging device assembly (20). In the exemplary embodiment, the rotor (24) is moved in the proximal direction by moving the rod string in the proximal direction. Once the rotor (24) has been positioned at the desired longitudinal rotor position relative to the stator (26), the position of the rotor (24) may be fixed by securing the rod string at the surface of the well or in any other suitable manner in order to maintain the position of the rotor (24) relative to the stator (26).

In the event that the rotor (24) subsequently requires repositioning without removing the progressing cavity pump (22) from the wellbore, the sequence described above may be repeated as is necessary.

In this document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that there be one and only one of the elements.