GB2323616A - Shifting tool and downhole sleeve - Google Patents

Abstract

A downhole sleeve (74) having a groove (72) is provided, with a tool for shifting the sleeve (74), comprising a body and a biased linkage (62). The biased linkage (62) is pivotally movable between a first retracted position and a second position in contact with the sleeve (74). The linkage (62) comprises a gripping link, longitudinally asymmetric and having a depression (75), which is rotatable between the two positions. When in the first position, a bottom surface (78) of the depression (75) has an inward inclination with respect to the sleeve (74). Rotation of the gripping link brings the depression (75) into substantial alignment with a projection (88) on said sleeve (74). A retaining element may be provided to retain the linkage (62) in the first position, and said element may be overcome by fluid-actuated means allowing the biased linkage (62) to move between the first and second positions.

Description

SHIFTING TOOL The field of this invention relates to tools useful for shifting sleeves and similar equipment downhole.

Sliding sleeves arc frequently employed in downhole operations. The sliding sleeves are incorporatcd in tubing or casing, and when properly positioned in the weilbore such sleeves need to be shifted to open or close ports to accomplish a wide varicty of downhole operations. Generally, sleeves have had an internal groove at eithcr end so that a shifting tool could be oriented in one direction to engage one of the grooves and oriented in the well in an inverse oricntation to engage the other groove on the shifting sleeve so that movement in the opposite direction could be achieved. These internal shifting grooves on sliding sleeves were engaged by dogs or collets that generally were radially loaded with coil & leaf springs so mat they could pass over the end of the shifting sleeve and spring back into the shifting groove for a connection to the sleeve to move it in one direction or the other. Typical of such prior designs are U.S. Patenis 4,917,191; 5,211,241; 5,183,114; 5,305,833; 5,090,481; and 5,156,210.

The drawback of prior designs is that, as they are biased further outward radially, the motive force keeping them in that position decreases as the coil or lear spring extends further and further. As a result, the force keeping the dogs, which engage the shifting sleeve in the engaged position, decreases as the dogs move radially outwardly, allowing the springs which drive them to expand. In many prior designs, the dogs were retained in a retracted position until the shifting tool reached the desired location. at which point a retainer would be moved out of the way, allowing the dogs to move outwardly into the shifting grooves on the sliding sleeve.

These prior designs had the drawbacks of not only a reduced pushing force on the dogs as they moved outwardly radially, but also the inherent unreliability of the small coil or leaf springs that had to be used in a very confined space in applications that called for a significant biasing force. Frequently, these springs would be subject to premature failure due to stress aacidng or attack from surrounding contaminants.

The use of springs behind the locking dogs to drive them further outwardly also entailed designs which had fairly large profiles, making that type of layout difficult to use in applications requiring smaller diameters where a more compact design was necessary.

The apparatus of the present invention was developed to address the shortcomings of these prior designs. In the present design, a pivoting linkage is employed to engage the shifting grooves in the shifting sleeve. As the linkage expands further outwardly, a greater locking force is applied to the shifting groove.

Jarring movements further increase the grip of the shifting tool of the present invention on the shifting sleeve. Additionally, the layout of the components is such that the pivoting linkage can be placed in an expanded position as the shifting tool is lowered toward the shifting sleeve, thereby allowing the linkage to compress as required to clear any obstructions along the way while springing out when finally contacting the groove on the shifting sleeve. The present design moves away from the leaf or small wire springs that had been previously used, and instead adopts a hydraulic actuation system which further involves the use of larger coil springs which provide greater flexibility to adjust the resulting force on the pivoting linkage when contacting the shifting sleeve.

According to the invention there is provided in combination a downhole sleeve having a groove and a tool for downhole shifting the sleeve, the tool comprising a body; a biased linkage selectively movable by pivoting action between a first retracted position and a second extended position in contact with the sleeve; said linkage comprising a gripping link which rotates on a pivot between said first and second positions, said gripping link having a longitudinally asymmetric shape and a depression, said depression, when said gripping link is in its said first position, having a bottom surface with an inward inclination with respect to the sleeve, where upon rotation of said gripping link said depression presents itself in substantial alignment with a projection on said sleeve.

The shifting tool is preferably hydraulically actuated. A built-up hydraulic force overcomes a retaining piston, which in turn frees up a pivoting linkage whose movements are opposed by a coil spring. The coil spring urges the pivoting linkage outwardly where contact can be made with the internal groove on a shifting sleeve. The shifting tool can be run in with the linkage in the expanded position since the parts are configured to allow the linkage to retract to dear any internal obstructions before rcaching the shifting grooves in the shifting sleeve. The pivoting action of the grip on the groove in the shifting sleeve increases the gripping force when jarring occurs. The parts are configured so that there is a minimum of movement of shifting parts which have seals to further reduce potential wear on these pressure seals. A compact design is provided which can be uscful on sleeves with a range of internal bores. The coil springs used in the preferred embodiment, which act against the linkage, can be easily replaced to adjust the force of engagemcnt with the internal groove on the shifting sleeve.

Figure 1 is a sectional view of the shifting tool in the run-in position.

Figure 2 is the vicw in Figure 1, with the tool in the shifted or engaged position with the groove on the sliding sleeve.

Figure 3 is similar to the view of Figure 1, but with hydraulic pressure applicd as the tool is being run in to indicate that the tool can assume the nm-in position when it encounters an obstruction during run iz Figure 4 illustrates the apparatus A in section view, showing in more detail the position of the components when it is engaged in the sleeve.

Figure 5 is the view of Figure 4 aftcr an emergency shcar release, showing the movement of the parts after the pin is sheared.

DFrAIl DESCRIPTION OF TE PREFERRED EMBODIMENT The apparatus A is shown in the nm-n position in Figure 1. It has a mandrel 10 having a central passageway 12. A ball seat 14 is disposed in passage 12 and is formed to accept a ball or sphere 16 so as to obstruct passage 12 for subsequent pressure build-up. While a ball and seat combination has bccn described, other mechanisms for obstructing or restricting the passage 12 to facilitate pressure build-up are within the purview of the invention, such as an orifice which creates backpressur: when flow is pumped through it A lateral port 18 comniunicates with vaiiable-volume cavity 20. Seals 22, 24, and 26 effectively seal cavity 20. Seals 24 and 26 are located in retaining piston 28. Retaining piston 28 has an outwardly oriented shoulder 30 which is aligned uith a shoulder 32 of linkage piston 34. Spring 3G is mounted over mandrel 10 and is supported by ring 38, whose position is retained by retainer 40 against shoulder 42 on mandrcl 10. One end of spring 36 bears on ring 38 while the other end bears on retaining piston 28. Sleeve 44 is mounted over mandrel 10, with scal 22 therebetween to sealingly close off one end of cavity 20. Sleeve 44 has an inwardly-oriented shoulder 46, which is aligned with the bottom 48 of linkage piston 34. In the preferred cmbodimcnt, springs 36 and 50 are coil springs, with spring 36 being stiffer thazi spring SO. Spring 50 is disposed between bottom 48 and shoulder 46, and is normally rctained in the compressed position shown in Figure 1 due to the greater force extended against retaining piston 25 by spring 36.

Because of this force imbalance, shoulder 30 firmly provides a travel stop to the linkage piston when its shoulder 30 engages shoulder 32 on the linlrvgc piston.

As shown in Figure 1, the linkage piston 34 can bc made of several compo nexts and includes an upper segment S2 which contains a depression 54 adjacent its cod. Adjacent the depression 54 is a projection 56. Proiection 56 is mounted into depression 58 on link 60. Link 60 has a projection 63 which cxtends into depression 54 of upper segment 52. As can be seen by comparing Figures 1 and 3 link 60 translates when the linkage piston 34 is allowed to move, as will be :explained below. Link 60 is pivotally connected to link 62 at pin 64. Link 62 is pivotally connected to link 66 by pin 68. Finally, link 66 is fixedly pinned at pin 70 for rotation about pin 70. However, longitudinally pin 70 is stationary. It should be noted that the distance from the ctntcrlinc 73 to the pin 68 is greater than the distance between the centerline 73 and the pin 61. As a result of this centerline distance difference. translational movement of linkage piston 34 puts an outward force on pin 64, encouraging it to move in the manner illustrated in Figure 2.

Link 66 has a special shape so that it may engage a groove 72 in the sleeve 74 which is to be shifted. In the position shown in Figure 2 the sleeve 74 can be urged downwardly to either open or close an opcning in a casing (not shown).

Those skilled in the art will appreciate that sleeve 74 has a groove similar to groove 72 at its other end. The apparatus A can be inserted in a reverse orientation to that snown in Figure 3 so that it may engage the scimitar groove on the sleeve 74 located at the other cnd of the sleeve from groove 72 for movement of the sleeve in an opposite dircction. The apparatus A can be run in the orientation shown in Figure 2 and at a later time rerun in the welibore in a reversed orientation to move the sleeve 74 in the opposite direction. Alternatively, an assembly can be put together so that the apparatus A can be stacked upon itself with one of the assemblies oriented in a manner shown in Figure 2 and the other in m arctoned orientation. In that situation, one or more ball seats, such as 14, can be provided, having differing dimensions to allow sequential operations of various assemblies of the apparatus A at different times as desired. Restricting orifices can be used as an alternate.

Referring now to Figures 1 and 2, it should be noted that the link 66 has an outwardly facing groove 75 which is defined by surfaces 76, 78, and 80. The angle between the surfaces 76 and 78 is close to a 900 angle ranging to an acute anglc. The angle between surfaces 78 and 80 is obtuse. As a result, surface 76, along with surface 82, dennes a projection 84 which, when link 66 is rotated to the position shown in Figure 2, extends into groove 72 of sleeve 74. In the retracted or first position shown in Figure 3 for link 66, surface 78 is oriented with a negative slope, i.e. with an inward inclination toward the longitudinal axis, indicated in Figure 3 by arrows 108.

When link 66 rotates to engage sleeve 74, surfaces 82 and 86, surface 86 forming the bottom of groove 72, windup facing each other in a parallel or nearly parallel orientation to facilitate grip on the sleeve 74. It should be noted that the angle cr movement of link 66 is fairly small, in the range of approximately 100, at the time surface 82 extends into groove 72. At that time, it is preferred that the alignment of surface 82 is parallel to surface 86 which forms a part of groove 72. With the parts so configured, the rotational motion of link 66 puts surfacc 82 into groove 72 in the same orientation as if the groove 75 tanslated radially outwardly. The angular rotation of link 62 is greater than the angular rotation of link 66 and is in the ordcr of approximatcly 30e in the position shown in Figure 2 in the preferred ernbodimenL The translational movement of link 60 is quite small, in the order of three eighths of an inch (0.95 cm). This minimal longitudinal movement of linkage piston 34 reduces wear on seals 24 and 26. It should be noted that prior designs involving shifting sleeves, which in one way or the other were uxd in conjunction with spring-loaded dogs, involve longitudinal movetneflts of such sleeves of as much as two inches (5.08 an) and norse, which caused a greater wear rate on the sealing nrechanis involved.

In the preferred embodiment, it is desirable to have the groove 75 in alignment with projection 88 which forms the end of the sleeve 74 to be shifted. When the links 62 and 66 are extended to the position shown in Figure 2 and are aligned as previously described, jarring motions in the direction of arrow 89 further ia- crease the grip of the linkage, comprised of links 62 and 66, to the sleeve 74.

It should be noted that while one linkage and actuating mechanism have becn illustrated, a plurality of linkages distributed around the circumference of the tool is contemplated. Each of the linkages has an equivalent to the links illustrated in Figures 1 and 2. Each such linkage is in turn connected to upper segment 52 of the linkage piston 34 for tandem actuation. When disposcd, as in the preferred embodiment, at 900 intervals and simultaneously actuated bv the linkage piston 34, the outward movement of the identical linkages 62 and 66 acts to centralize the apparatus A within the sleeve 74, as well as to distribute the forces all around the sleeve 74 to facilitate its movement in the uphole or downhole direction with an application of a uniform force around its circumference.

In operation, the passage 12 should be obstructed so that hydraulic pressure can be built up in passageway or pon 18. This is accomplished by dropping a ball or sphere 16 onto a ball seat 14 or in any othcr way obstructing the passage 12.

A restricting orifice which creates a backpressure is another way to build pressure.

Pressure is built up from the surface which communicates with variable-volume cavity 20 through the port is. Upon an increase in pressure, as represented by arrow 90, the retaining piston 28 shifts from the position shown in Figure 1 to the position shown in Figure 2. In so doing, it compresses the spring 36. Once the force applied by spring 36 on retaining piston 28 is defeated. sprmg 50 is now free to move the linkage piston 34 W such time as shouldcr 32 again contacts shoulder 30 on the retaining piston 28 or link 66 contacts the groove 72, whichever occurs first. As long as the pressure is maintained in port 18, the retaining piston 28 is taken out of consideration and the linkage piston 34 is tice to translate against the opposing force of spring 50. Accordingly, the apparatus A may be run into the wilborc under pressure, such as when it is run on a coiled tubing. If any obstructions are encountered as the apparatus A is run into the wellbore, the obstructions would then impact link 66 and force it back toward the position shown in Figure 1 from the position shown in Figure 2, tetriporarily ovcrcoming the force of spring 50. Once the obstruction is cleared, the link 66 can then rotate back outwardly undcr the force applied indirectly through spring 50 through the linkage. Figure 3 illustrates running in while under pressure, with arrow 90 indicating pressure applied. It can be secn that there is a gap betwecn shoulders 30 and 32. This is because the link 66 is pushed back into the run-in position when hitting an obstruction 92 schematically illustrated in Figure 3. It can be readily appreciated that as long as the pressure represented by arrow 90 is maintained, link 66 will again rotate radially outwardly in a counterclockwise manner once it clcars the obstruction 92. In the position shown in Figure 3, the piston 34 has a range of motion available represented by the gap betwecn shoulders 30 and 32.

There is an emergency release feature which is also illustrated in Figures 2, 4 and 5. As shown in Figures 4 and 5, mandrel 10 has a top sub 94 to which is connected an outer sleeve 96. Extending through outer sleeve 96 is a bore 98. A guiding sleeve 100 is disposed between outer sleeve 96 and anchor sleeve 102.

Anchor sleeve 102 supports pin 70 to which link 66 is connected. At its lower end, guiding sleeve 100 extends over link 60 Lo guide it in its longitudinal move- ment. Guiding sleeve 100 further has a recess 104 which is aligned 'with borc 98 of sleeve 96. A shear screw 106 cxtcnds through bore 98 into recess 104 to sccure the position of guiding sleeve 100. As shown in Figure 4, the guiding sleeve 100 is locked against anchor sleeve 102, which would otherwise translate but for the existence of shear screw 106. When an emergency release is desired, a sufficient downward jarring force is applied while the apparatus A is in the position shown in Figure 4. When sufficient stress is transmitted through the top sub 94 to the outer sleeve 96,. the shcar pin 106 can shcar. Once that occurs, the assembly of the guiding sleeve 100 and anchor sleeve 102 are frce to translate toward top sub 94.

Once this occurs, pin 70 moves longitudinally toward top sub 94, thus retracting the linkage by allowing link 66 to rotate in a clockwise direction. It should be noted that the outcr sleeve 96 further promotes the clockwise rotation of link 66 when shear pin 106 is sheared since movement of pin 70 toward top sub 94 rotates link 66 into alignment with outer sleeve 96 so that link 66 can advance under sleeve 96. Eventually, when sufficient clockwise rotation of link 66 has occurred to disengage from the groove 72 of sleeve 74, the apparatus A may be r-tneved.

Pulling upon top sub 94 facilitates this disengagement. It should also be noted that in the emergency release procedure, shcar pin 106 is sheared which encourages the entir lixkagc to move toward and partially within outer sleeve 96, thereby instisut- ing the clockwise rotation of link 66 to facilitate the disengagemcut from the groovy 72 of sleeve 74. These motions are il!ustratcd in more detail in Figures 4 and 3. The use of coil spnngs reduces failure which occurred in prior designs using leaf or small wire springs. Using the pivot action of links 66 and 62 inaeases the mechanical advantage of the force applied by spring 50. A more compact design is presented which can service a range of sleeve sizes. Wear on seals 24 and 26 is minimizcd as a very small longitudinal movement is magnified by a far greater radial movement of links 62 and 66.

The forcgoing disclosure and description of the invention are illustrative and explanatory thC?cOf, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without dcparting from the spirit of the invention.

Claims (2)

1. In combination a downhole sleeve having a groove and a tool for downhole shifting the sleeve, the tool comprising: a body; a biased linkage selectively movable by pivoting action between a first retracted position and a second extended position in contact with the sleeve; said linkage comprising a gripping link which rotates on a pivot between said first and second positions, said gripping link having a longitudinally asymmetric shape and a depression, said depression, when said gripping link is in its said first position, having a bottom surface with an inward inclination with respect to the sleeve, where upon rotation of said gripping link said depression presents itself in substantial alignment with a projection on said sleeve.

2. The combination of Claim 1, further comprising: a retaining element to hold said linkage in said first position; fluid-actuated means for overcoming said retaining element, allowing said biased linkage to move between said first and second positions to clear an obstruction as the tool is run into the wellbore.