US3430698A - Selectively operable anchoring system - Google Patents

Description

United States Patent 3,430,698 SELECTIVELY OPERABLE ANCHORING SYSTEM Harold J. Urbanosky, Houston, Tex., assignor to Schlumberger Technology Corporation, Houston, Tex., a corporation of Texas Filed June 29, 1967, Ser. No. 651,348

US. Cl. 166-212 21 Claims Int. Cl. E211) 23/04 ABSTRACT OF THE DISCLOSURE The particular embodiment described herein as illustrative of one form of the invention is directed to anchoring apparatus for well tools. To accomplish this, the disclosed tool includes a selectively-operable hydraulic system for moving a wall-engaging member into and out of its retracted and extended positions. Means are also provided to disable the anchoring tool without loss of hydraulic fluid upon application of tension to the suspension cable.

Accordingly, as will subsequently become apparent, the present invention pertains to well tools; and, more particularly, the present invention is directed to new and improved apparatus for selectively anchoring a well tool in a well bore.

Heretofore, to selectively anchor a well tool in a well bore, various arrangements of laterally-extendible Wallengaging members have been employed. Typical of such arrangements is that shown in Patent No. 3,011,554 to Robert Desbrandes, which discloses a wall-engaging member mounted on laterally movable piston members operatively arranged in piston chambers within the disclosed tool. A hydraulic system connected to these piston chambers includes a pressure-multiplying piston which, when actuated by admission of well bore fluids into the cylinder carrying the pressure-multiplying piston, will develop an increased hydraulic pressure suflicient to extend the pistons and urge the wall-engaging member against the well bore wall. Once it is actuated, the hydraulic system will remain at whatever pressure is developed by the pressuremultiplying piston. To retract the wall-engaging member, the hydraulic pressure is ordinarily relieved by discharging the hydraulic fluid into a so-called dump chamber in the tool that is initially at a low pressure. Provisions are also made in the Desbrandes tool to discharge the hydraulic fluid into the well bore should there be a malfunction preventing the normal retraction of the wall-engaging member.

Although this and similar arrangements have been successful, there are nevertheless various problems connected with such systems. For example, should there be a leak at any point in the hydraulic system, the developed pressure will decrease at a rate proportional to the magnitude of the leak. Thus, in time, the wall-engaging member will no longer be urged against the well bore wall with sufficient force to anchor the tool as desired. Moreover, once the pressure is relieved in the hydraulic system, the wallengaging member cannot be re-extended and the tool must be returned to the surface for servicing. Similarly, should it be necessary to discharge the hydraulic fluid to the well bore as an emergency measure, the tool must then be dismantled and reconditioned before it can be used again.

Accordingly, it is an object of the present invention to provide a new and improved repetitively-operable anchoring system for Well tools, which system is also so arranged that it can be selectively disabled from the surface without requiring significant reconditioning before the tool can be re-used.

This and other objects of the present invention are obtained by providing on a well tool an enclosed reservoir space for a pressure fluid and an extendible pressure- "ice actuated piston member. Selectively-directed pressuredeveloping means, such as a reversible pump, are connected between the fluid reservoir and each side of the piston member in such a manner that by alternatively connecting the pressure-developing means to one or the other of the two sides of the piston member, the piston member will be selectively extended and retracted. To enable the piston member to be returned to its usual position should there be a malfunction in the pressure system, normally-closed valve means are connected between one side of the piston member and an enclosed chamber that is normally at a reduced pressure. Actuating means responsive to a predetermined movement of the well tools suspension member are operatively arranged to open the normally-closed valve means and discharge a suflicient quantity of the pressure fluid into the enclosed chamber that the piston member will return to its usual position.

The novel features of the present invention are set forth with particularity in the appended claims. The operation together with further objects and advantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in which:

FIGURE 1 shows a well tool including an anchoring system in accordance with the present invention as it will appear in a well bore;

FIGURE 2 is a diagrammatic representation of an anchoring system employing the principles of the present invention; and

FIGURES 3 and 4 respectively illustrate certain details of a preferred embodiment of the anchoring system depicted in FIGURE 2.

Turning now to FIGURE 1, a well tool 10 is shown as it will appear when suspended in a borehole 11 from a suspension member such as a cable 12 having one or more electrical conductors (not shown in FIGURE 1). Since the tool 10 could just as well be any typical openhole or cased-hole tool employing a wall-engaging anchor, only a brief description of the tool itself is required to illustrate a typical application of the present invention.

Accordingly, the tool 10 may well be the tool fully described in a copending application Ser. No. 649,976, for obtaining one or more elongated formation samples, as at 13, from an earth formation 14 traversed by the borehole 11. To accomplish this, the tool 10 includes a number of tandemly connected housings 1519. One or more of the housings, as at 15 and 17, are arranged to enclose various electrical and electronic means for locating the tool 10 at a desired position in the borehole 11 as well as for controlling various electrical devices (not shown) in the tool. The anchoring apparatus 20 of the present invention is preferably enclosed in the next housing 16. As will sub sequently become more apparent, the anchoring apparatus 20 includes an extendible wall-engaging member 21 which, when extended against one wall of the borehole 11, will urge the forward face of the tool 10 against the opposite wall of the borehole.

The next lower housing 17 of the tool 10 encloses suitably arranged motive means (not shown) for supporting and driving a pair of similar rotatable cutting wheels 22 operatively arranged in outwardly-converging vertical planes. Means (not shown) are provided in the housing 18 for carrying the cutting wheels 22 upwardly and, as they first move upwardly, extending the wheels through an opening 23 along the forward face of the housing. As the cutting wheels 22 are extended, they will begin cutting their way into the adjacent wall of the borehole 11. Then, upon further upward travel of the cutting wheels 22, an elongated prismatic formation sample 13 will be cut out of the wall of the borehole 11. As the cutting wheels 22 approach the upper limit of their travel, they are retracted and then subsequently returned to their initial position near the bottom of the housing Opening 23. Once the formation sample 13 is freed (upon retraction of the cutting wheels 22 at the upper limit of their travel) the sample will fall through the housing opening 23 and be collected in a sample receiver in the lowermost housing 19 of the tool 10. Additional samples, as at 13, can be obtained by retracting the wall-engaging mem ber 21 and repositioning the tool at different locations in the borehole 11.

Turning now to FIGURE 2, a schematic representation is shown of a preferred arrangement of the anchoring apparatus of the present invention. In general, the anchoring apparatus 20 includes a fluid reservoir 24 which may conveniently be in the upper portion of the housing 16. In one manner of closing the upper end of the reservoir 24, the lower end of the upper tool housing 15 is telescopically fitted into the upper end of the anchor housing 16 and fluidly sealed in relation thereto by one or more suitable sealing members 25. The lower end of the reservoir 24 is closed as, for example, by a transverse wall 26 across the lower end of the housing 16. For reasons that will subsequently become apparent, the lower portion of the housing 16 is divided into two separate chambers 27 and 28 by longitudinally spaced transverse walls 29-31 above the wall 26 at the lower end of the housing. A suitable pressure fluid, such as a typical hydraulic oil or the like, is introduced through one or more conveniently located filling ports (not shown) in the housing 16 until the reservoir 24 is filled. Once the reservoir 24 is filled, these filling ports are, of course, closed.

The wall-engaging member 21 is preferably mounted outside of the housing 16 on the free end of one or more piston members having forward reduced-diameter portions 32 and rearward enlarged-diameter portions 33 that are respectively arranged for lateral travel in piston chambers 34 formed at convenient locations in the housing. The forward piston portions 32 are extended through the side of the housing 16 and fluidly sealed thereto by sealing members 35. Similarly, the enlarged rearward piston portions 33 are fluidly sealed by sealing members 36 to the walls of the piston chambers 34 to define therein separate enclosed spaces 37 and 38 ahead of and behind the enlarged piston portions.

Pressure-developing means, such as a typical gear pump 39 driven by a reversible electric motor 40, are mounted in the housing 16 and preferably within the reservoir 24 itself. Since the pump 39 can be driven in alternate directions (as indicated by the arrows 41 and 42) typical check valves 43 and 44 are connected to the fluid lines 45 and 46 on each side of the gear pump and respectively arranged to open only to admit fluid from the reservoir 24 to their associated fluid line. Thus, at any given time, only one or the other of the check valves 43 and 44 will be open to admit fluid from the reservoir 24 to either the conduit 45 or the conduit 46 depending, of course, upon which direction (41 or 42) the pump 39 is running.

Accordingly, when the pump 39 is being driven in the direction indicated by the arrows 41, the conduit 45 will be connected to what is then the suction side of the pump and the check valve 43 will be open to admit fluid from the reservoir 24 through the conduit 45 to the pump. The other conduit 46 will then be on the discharge side of the pump 39 and the check valve 44 will remain closed. On the other hand, when the pump 39 is running in the opposite direction 42, it will take suction through the nowopen check valve 44 and the conduit 46. The check valve 43 will then be closed since the conduit 45 is on the discharge side of the pump 39.

The other end of the conduit 46 is connected to the enclosed spaces 37 ahead of the enlarged piston portions 33. Thus, whenever the pump 39 is being driven in the direction shown by the arrows 41, fluid will be taken from the reservoir 24 through the check valve 43 and delivered under pressure by way of the conduit 46 to the enclosed reverse direction. As indicated diagrammatically by the unbroken line 49, the three-Way valve 47 is arranged to permit flow between the conduit 45 and a conduit 50 connected between the common port of the three-way valve and the enclosed piston spaces 38 behind the enlarged piston portions 33. Thus, so long as the three-way valve 47 is in its normal position shown in FIGURE 2, whenever the pump 39 is driven in the direction shown by the arrows 42, fluid will be taken from the reservoir 24, through the check valve 44 and delivered under pressure through the conduit 45,three-way valve 47, and the conduit 50 to the rearward enclosed piston spaces 38. This will, of course, be effective to extend the wall-engaging member 21.

It will be appreciated, of course, that steps should be taken to accommodate volumetric changes in the fluid in the reservoir 24 due to temperature variations as well as to maintain the reservoir fluid at the same pressure as that of the fluids in the borehole 11. Accordingly, a piston member 51 is slidably disposed in the chamber 28 and fluidly sealed therein by a sealing member 52. A port 53 in the wall of the housing 16 is arranged to admit borehole fluids below the piston 51 and, since the remaining space in the chamber 28 above the piston is also filled with the hydraulic fluid, maintain the hydraulic fluid in the chamber at the borehole pressure. To provide fluid communication between the chamber 28 and reservoir 24, a tubular member 54 is preferably extended along the longitudinal axis of the housing 16 through the transverse walls 29-31 and fluidly sealed to each of these walls. One or more lateral ports 55 in the tubular member 54 are provided to allow hydraulic fluid to flow between the reservoir 24 and the chamber 28. The piston member 51 is, therefore, made annular and is free to move relative to the fixed tubular member 54, with a fluid seal 56 therebetween fluidly sealing the members to one an other. Thus, the piston 51 is free to move in relation to the housing 16 and maintain the pressure in the reservoir 24 at borehole pressure as well as to accommodate volumetric changes therein.

As a matter of convenience, electrical conductors, as at 57, that must be connected to various components in the housing 16 as well as routed to other portions of the tool 10 are brought through suitable conductor seals, as at 58, and carried through the housing and tubular member 54 to other conductor seals, as at 59, in the lower end wall 26. These conductors 57 could, of course, just as well be routed outside of the reservoir 24.

Turning now to the operation of the anchoring apparatus 20. The Wall-engaging member 21 is, of course, retracted while the tool 10 is being moved to a desired depth in the borehole 11. Once it is determined that the wall-engaging member 21 is to be extended, by means of typical circuitry (not shown) at the surface as well as in the housings 15 and 17, a suitable source of electrical power (not shown) is connected to the motor 40 by its conductors 40a to drive the pump 39 in the direction indicated by the arrows 42. As the pump 39 is driven in this manner, fluid will be drawn to the pump from both the forward enclosed spaces 37 and by way of the check valve 44, from the reservoir 24. The combined fluid will then be pumped on through the conduit 45, the threeway valve 47 (by way of the normally-open path 49 therethrough), and the conduit 50 leading to the enclosed spaces 38 behind the enlarged piston portions 33. This will, of course, be effective to move the wall-engaging member 21 to its extended position.

Once the wall-engaging member 21 has contacted one wall of the borehole 11 and moved the forward face of the tool against the opposite borehole wall (as shown in FIGURE 1), continued operation of the pump 39 will, of course, begin increasing the pressure in the rearward piston spaces 38. Since this pressure would continue to increase, means, such as a typical pressure switch 60 that may be connected to the conduit 45, are provided for stop ping the pump motor 40 once the pressure in the piston spaces 38 reach a magnitude suflicient to hold the Wallengaging member 21 against the wall of the borehole 11 with a desired force. Thus, by connecting the conductors 40a and 60a of the pump motor 40 and pressure switch 60 by way of suitable circuitry (not shown), the pump 39 will be halted once the pressure in the piston spaces 38 reach the predetermined cut-01f setting of the pressure switch.

Ordinarily, the pressure in the piston spaces 38 will remain relatively constant once the pump 39 is halted. Should there be leakage of some nature or should the wall-engaging member 21 move further outwardly into, for example, a soft place in the formation 14, the pressure in the piston spaces 38 will decrease. Thus, to maintain the pressure in the enclosed spaces 38 within a desired range, the pressure switch 60 is also arranged and suitably connected to the pump motor 40 to restart the pump 39 should the pressure in the rearward enclosed spaces drop below a predetermined pressure. These settings for the pressure switch 60 will, of course, be selected to keep the pressure in the spaces 38 at a level calculated to maintain the tool 10 anchored with at least a force sufficient to hold it in position in the borehole 11.

The retract the wall-engaging member 21, the pump 39 is driven in the direction indicated by the arrows 41. Simultaneously with the starting of the motor 40, a typical solenoid-actuated valve 61 connected to the conduit 45 is opened (by means of suitable circuitry at the surface) to enable fluid in the enclosed spaces 38 to be drained (by way of conduits 50 and 45 and the valve 47) back to the reservoir 24. The check valve 48 will, of course, prevent this fluid from returning by way of the conduit 45 to the pump suction. As fluid is withdrawn from the enclosed spaces 38, the pump 39 will be simultaneously removing fluid from the reservoir 24 by way of the check valve 43 and pumping it into the forward enclosed piston spaces 37 to retract the wall-engaging member 21. Once the wall-engaging member 21 is fully retracted, the pump motor 40 will be stopped and the solenoid-actuated valve 61 reclosed. The anchoring apparatus 20 is then again in readiness for repeating the abovedescribed operations. It will be recognized, of course, that any volumetric changes in the reservoir 24 during these operations will be accommodated by movement of the piston 51.

The above-described operations will ordinarily be sufficient for the full use of the anchoring apparatus 20. It will be appreciated, however, that malfunctions can occur in even the best of well tools. Accordingly, as another aspect of the present invention, means are provided to insure that the wall-engaging member 21 can always be retracted should any portion of the anchoring apparatus 20 fail while the tool 10 is anchored. To accomplish this, means are provided to disable the hydraulic system in response to movement of the suspension cable 12.

Accordingly, as best seen in FIGURE 2, an annular piston member 62 is slidably disposed in the chamber 27 around the tubular member 54 and fluidly sealed therein by sealing members 63 and 64. The piston 62 is initially positioned at the upper end of the chamber 27 and held there by the friction of the sealing members 63 and 64. A conduit 65 is connected between the space in the chamber 27 above the piston 62 to the normally-closed port of the three-way valve 47. An access port in the housing 16 is provided to provide communication into the chamber 27, with a suitable closure member 66 normally closing the port. Thus, in the usual case, the three-way valve 47 will remain closed and block communication to the chamber 27 which is initially empty and at atmospheric pressure.

It Will be appreciated, therefore, that once the threeway valve 47 is shifted to open flow (as shown by the diagrammatic path 67) between the common port and normally-closed port of the three-way valve, direct communication is established (by way of the conduits 50 and 65) between the rearward enclosed spaces 38 and empty chamber 27. Thus, actuation of the three-way valve 47 Will be effective to drain the hydraulic fluid in the rearward piston spaces 38 into the empty chamber 27 and reduce the pressure therein sufliciently to retract the wall engaging member 21.

To actuate the three-way valve 47, one end of an actuating member 68 is connected to the valve and the other end of the actuating member is connected to the lower end of the upper tool housing 15 as shown in FIG- URE 2. It will be appreciated, of course, that the telescoping arrangement of the adjacent ends of the housings 15 and 16 will permit one to move relative to the other. To limit the extent of this relative movement, means are provided such as an outwardly directed shoulder 69 on the lower end of the upper tool housing 15 is spaced below and arranged to engage an inwardly directed shoulder 70 on the lower housing 16.

Accordingly, should there be a malfunction in the hydraulic system of the anchoring apparatus 20 while the tool 10 is anchored as shown in FIGURE 1, the suspension cable 12 will be tensioned sufficiently to fail one or more shear members, as at 71, which ordinarily secure the housings 15 and 16 to one another. Once the shear member 71 fails, the upper housing 15 will be free to move upwardly in relation to the anchored housing 16 until the shoulders 69 and 70 engage. This upward movement will be suflicient to act through the actuating member 68 and shift the three-way valve 47 to its other position to open communication between the piston spaces 38 and empty chamber 27. It should be noted that the sealing members 25 will keep the reservoir 24 still sealed.

Once the anchoring apparatus 20 has been disabled in this manner, it is, of course, necessary to return the tool 10 to the surface. It will be recognized that the piston 51 will still be effective to maintain the reservoir 24 at the pressure exterior of the tool 10. Moreover, once the threeway valve 47 has been shifted, the flow path 49 therethrough will be blocked to close off the conduit 45.

After the tool 10 has reached the surface, the reservoir 24 will be at atmospheric pressure and the oil-filled system will still be sealed. Thus, to restore the anchoring system 20 to its original condition, it is necessary only to remove the closure member 66 and return the piston 62 to its initial position as, for example, by connecting a source (not shown) of a pressure fluid to the port usually closed by the closure member. As the piston 62 is moved upwardly, it will displace the hydraulic fluid from the chamber 27 (by way of a check valve 72) back into the reservoir 24. Then, once the housings 15 and 16 are restored to their initial positions to reposition the three-way valve 47 and the shear member 71 is replaced, the anchoring apparatus 20 will be ready for further service. It will be appreciated that these simple steps will require little time and that the sealing integrity of the hydraulic system will at no time be impaired.

Turning now to FIGURE 3, a preferred embodiment is shown of the three-way valve 47, with the portions thereof previously described being designated by the same reference numerals. In general, therefore, the valve 47 is comprised of a body 73 having a longitudinal bore 74 therethrough which is preferably closed at its lower end by a removable closure member 75. The conduits 45, 50 and 65 are respectively connected to longitudinally spaced ports 7 67 8 along one side of the valve body 73, with each port being appropriately arranged to intersect the l0ngi tudinal bore 74. For reasons that will subsequently become apparent, a branch passage 79 is connected between the port 77 and the lower portion of an enlarged portion 80 of the longitudinal bore 74. An elongated valve member or spool member 81 is slidably disposed in the longitudinal bore 74, with the upper end of the valve spool being connected to or made integral with the lower end of the actuating member 68. The lower end of the valve spool 81 is arranged to extend into the enlarged bore portion 80 so long as the spool is in its normal position as shown in FIGURE 3.

To improve the flow characteristics of the three-way valve 47 between the ports 76 and 77 (the normallyopen flow path 49 shown in FIGURE 2), the longitudinal bore 74 is preferably enlarged, as at 82 and 83, opposite each of these two ports and that portion of the spool member 81 normally spanning these ports is slightly reduced as at 84. Sealing members 85 and 86 around the spool 81 above and below the reduced spool portion 84 are provided to allow fluid flow between the ports 76 and 77 but block flow further along the longitudinal bore in either direction so long as the spool mmeber 81 is in its normal position as shown in FIGURE 3. Another sealing member 87 immediately below the reduced spool portion 84 is arranged to be fluidly sealed in the longitudinal bore 74 and block flow between the ports 76 and 77 whenever the spool member 81 is shifted upwardly by the actuating member 68.

Returning for the moment to FIGURE 2, it will be realized that when the anchoring apparatus 20 is disabled, all of the fluid in the hydraulic system will be at a substantially greater pressure than that in the empty chamber 27. Moreover, to retract the wall-engaging member 21, it is necessary to exhaust only the fluid in the enclosed piston spaces 38 to the chamber 27 and any further discharge of hydraulic fluid therein will only make it necessary to further enlarge the empty chamber and, thereby, needlessly increase the size of the anchoring ap paratus 20. It will be appreciated, therefore, that to avoid oversizing of the chamber 27, means must be provided to insure that the flow path 49 is positively closed before the flow path 67 is opened to be certain that only the hydraulic fluid then present in the enclosed spaces 38 enters the chamber 27. Otherwise, unless such measures are taken, the substantial pressure differentials could well result in the empty chamber 27 being filled, at least in part, with fluid from the reservoir 24 and prevent the complete exhaust of the fluid in the enclosed spaces 38. This latter situation would, of course, prevent the wall-engaging mmeber 21 from being fully retracted when the anchoring apparatus 20 is disabled Accordingly, as seen in FIGURE 3, the present invention includes delayed-operating valve means for further insuring the complete blocking of flow between the ports 76 and 77 (the flow path 49) well before flow is established between the ports 77 and 78 (the flow path 67). To accomplish this, an annular piston member 88 is slidably disposed in the enlarged bore portion 80 and suitably positioned by a stop, as an upright projection 89 on the closure member 75, above the point at which the branch passage 79 enters the enlarged bore portion 80. The upper face of the annular piston 88 is suitably shaped to form a valve seat 90 for receiving the complementarily shaped lower end 91 of the spool member 81. A sealing member, such as an O-ring 92 around the spool end 91, completes the sealing engagement of the spool end with the valve seat 90. A compression spring 93 between the closure member 75 and piston 88 normally urges the piston member into seating engagement with the spool end 91. It will also be recognized that since the upper face of the piston 88 is normally exposed to the greatly reduced pressure of the empty chamber 27, the high pressure of the fluid in the branch passage 79 will also be urging the piston member 88 into seating engagement with the spool end 91.

In this manner, when the actuating member 68 is first pulled upwardly to disable the anchoring apparatus 20, the sealing member 87 is well-seated within that portion of the longitudinal bore 74 between the ports 77 and 76 before the upper face of the piston 88 engages the shoulder 94 formed at the junction of the longitudinal bore and enlarged bore portion 80. During this point in the travel of the spool member 81, there will be no significant pressure differential between the ports 77 and 76 so that the sealing member 87 will not be damaged by closing against a high pressure differential. Moreover, the extreme pressure differential acting across the piston 88 will still be effective to maintain the valve seat 90 tightly sealed against the end 91 of the upwardly-moving spool member 81.

Once, however, the piston member 88 engages the shoulder 94, further upward travel of the spool member 81 (which is permitted by suitably arranging the spacing between the two opposed housing shoulders 69 and will then allow the spool end 91 to move away from the valve seat on the now-halted piston 88. Once the spool end 91 is separated from the valve seat 90, communication is, of course, established (flow path 67) between the piston spaces 38 and the empty chamber 27 to complete the disabling operation of the anchoring apparatus 20.

As the tool 10 is returned to the surface following the above-described disabling operation, the operation of the piston member 51 will be effective to reduce the pressure in the reservoir 24 and enclosed spaces 37 as the borehole pressure is correspondingly reduced. The pressure of the exhausted fluid now in the chamber 27 will be low (in the order of only a few hundreds of pounds/ sq. inch) but will at some point in the ascent of the tool 10 become great enough to at least partially re-extend the wall-engaging member 21. Thus, although the check valve 72 will in time open to relieve at least some of the pressure in the chamber 27, flow-restriction means, such a reduction in the bore 95 through the piston 88, are arranged between the chamber 27 and valve 47. This flow restriction 95 will prevent any significant flow of fluids from the chamber 27 to the enclosed spaces 38 and thereby enable the check valve 72 to function better.

It will, of course, be appreciated that the valve 47 is fully restored to operation by returning the actuating member 68 to its original position. No particular attentiono, is required, therefore, for the valve 47 when the anchoring apparatus 20 is readied for further service.

Turning now to FIGURE 4, a preferred embodiment is shown of one manner in which the wall-engaging member 21 can be mounted. In general, to obtain maximum lateral travel of the wall-engaging member 21, it is mounted on the forward ends of two longitudinally spaced pistons 96. The rearward ends 97 of each of these pistons 96 are enlarged and fluidly sealed within the inner one of two telescoped sleeves 98 and 99 themselves telescopically received in spaced lateral bores 100 in the housing 16. By fluidly sealing the forward and rearward ends of the outer sleeves 98 to the walls of the bores 100, as at 101 and 102, an enclosed annular space 103 is provided around the outer sleeves which are in communication with the conduit 46. Similarly, the inner sleeves 99 are appropriately sealed in relation to the outer sleeves 98 and the piston members 96 to define enclosed annular spaces 104 and 105 between the sleeves and between the inner sleeves and piston members. Longitudinal passages 106 and 107 through the sleeve members 98 and 99, respectively, are provided to place the enclosed annular spaces 103-105 in communication with one another and the conduit 46. It will be recognized, of course, that these annular spaces 103-105 and passages 106 and 107 altogether correspond to the above-described enclosed spaces 37. The spaces 38 behind the pistons 96 and sleeves 98 and 99 are, of course, connected to the conduit 50 (not seen in FIGURE 4). It will be appreciated, therefore, that the wall-engaging member 21 will be capable of extending as far as the combined extended length of the pistons 96 and sleeves 98 and 99 without requiring any greater length than if only the pistons 96 were employed.

Accordingly, it will be recognized that the present invention has provided a new and improved anchoring system for well tools. By employing the present invention, the anchoring member can be selectively extended and retracted at will to permit a well tool to be repetitively anchored in a well bore. Moreover, means are provided in the present invention for selectively disabling the anchoring apparatus should some malfunction occur to prevent the usual retraction of the wall-engaging member. By employing the selectively operable valve of the present invention which responds to a predetermined tension on the tools suspension member, the anchoring system can be positively disabled without any special procedure being required.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. A well tool adapted for reception in a well bore comprising: a support adapted for connection to a suspension member; anchoring means on said support and including a piston cylinder, a piston member in said cylinder and movable therein between spaced positions, a wallengaging member, and means connecting said wall-engaging member to said piston member for movement in relation to said support between extended and retracted positions; means selectively operable from the surface for alternately moving said piston member between its said positions including pressure-developing means connected to said piston cylinder and containing a fluid for developing fluid pressures suflicient to move said wall-engaging member between its said extended and retracted positions; and disabling means adapted for response to a predetermined movement of a suspension member connected to said support for relieving the fluid pressure applied to said piston member without loss of said fluid to return said wall-engaging member from its said extended position to its said retracted position.

2. The well tool of claim 1 further including: pressureresponsive means operatively connected to said pressuredeveloping means for maintaining the fluid pressure supplied to said piston cylinder within a predetermined range suflicient to urge said wall-engaging member toward its said extended position with corresponding force.

3. The well tool of claim 1 further including: pressureresponsive means for limiting the fluid pressure supplied to said piston cylinder.

4. The well tool of claim 1 further including: pressureresponsive means operatively connected to said pressuredeveloping means for limiting the fluid pressure supplied to said piston cylinder and for maintaining the fluid pressure supplied to said piston cylinder at a level sufiicient to urge said wall-engaging member toward its said extended position with a corresponding predetermined force. include: an enclosed chamber normally at a reduced pressure; normally-closed valve means between said pressuredeveloping means and said enclosed chamber; and actuating means connected to said valve means and adapted for connection to a suspension member for opening said valve means upon a predetermined movement of such a suspension member.

5. The well tool of claim 1 wherein said disabling means 6. The well tool of claim 5 further including: a piston in said enclosed chamber and movable therein from a first position to a second position upon entrance of said fluid; and means adapted for restoring said piston to its said first position to return said fluid to said pressure-developing means.

7. A well tool adapted for reception in a well bore comprising: a support including first and second portions movable relative to one another, said first portion being adapted for connection to a suspension member, and means normally securing said first and second portions to one another and releasable upon application of a predetermined force on such a suspension member to free said first and second portions for movement relative to one another; anchoring means on said second support portion and including a piston member in a cylinder and movable therein between spaced positions, a wall-engaging memher, and means connecting said wall-engaging member to said piston member for movement in relation to said support between extended and retracted positions; means selectively operable from the surface for alternately moving said piston member between its said positions including a fluid reservoir adapted to contain a fluid and fluidpumping means connected between said reservoir and said piston cylinder for developing fluid pressures suflicient to move said wall-engaging member between its said extended and retracted positions; and disabling means responsive to relative movement of said support portions for relieving the fluid pressure applied to said piston memher without loss of such fluid to return said wall-engaging member from its said extended position to its said retracted position.

8. The well tool of claim 7 further including: pressureresponsive means operatively connected to said fluid-pumping means for maintaining the fluid pressure supplied to said piston cylinder within a predetermined range sufiicient to urge said wall-engaging member toward its said extended position with corresponding force.

9. The well tool of claim 7 further including: pressureresponsive means operatively connected to said fluid-pumping means for limiting the fluid pressure supplied to said piston cylinder.

10. The well tool of claim 7 further including: pressureresponsive means operatively connected to said fluid-pumping means for limiting the fluid pressure supplied to said piston cylinder and for maintaining the fluid pressure supplied to said piston cylinder at a level suflicient to urge said wall-engaging member toward its said extended position with a correspondin predetermined force.

11. The well tool of claim 7 wherein said disabling means further include: an enclosed chamber normally at a reduced pressure; normally-closed valve means between said piston cylinder and said enclosed chamber; and actuating means connected between said valve means and said first support portion for opening said valve means upon a predetermined movement of such a suspension member.

12. The well tool of claim 11 further including: a piston in said enclosed chamber and movable therein from a first position to a second position upon entrance of said fluid; and means adapted for restoring said piston to its said first position to return said fluid to said reservoir.

13. The well tool of claim 7 wherein said disabling means further include: an enclosed chamber normally at a reduced pressure; normally-closed first valve means between said piston cylinder and said enclosed chamber; normally-open second valve means between said fluidpumping means and said piston cylinder; and actuating means connected between said first and second valve means and said first support portion for opening said first valve means and closing said second valve means upon a predetermined movement of such a suspension member.

14. The well tool of claim 13 further including: means for delaying the opening of said first valve means until said second valve means are closed.

15. The well tool of claim 7 wherein: said anchoring means further include first and second conduits respectively connecting said fluid-pumping means to said piston cylinder on opposite sides of said piston member whereby fluid pressure in said first conduit will move said wallengaging member to its said retracted position and fluid pressure in said second conduit will move said wall-engaging member to its said extended position; and said disabling means further include an enclosed chamber normally at a reduced pressure, normally-closed first valve means and passage means between said second conduit and said enclosed chamber, normally-open second valve means in said second conduit between said fluid-pumping means and said piston cylinder, and actuating means connected between said first and second valve means and said first support portion for opening said first valve means and closing said second valve means upon a predetermined movement of such a suspension member.

16. The well tool of claim 15 further including: means for delaying the opening of said first valve means until said second valve means are closed.

17. A Well tool adapted for reception in a well bore comprising: a support adapted for connection to a suspension member; means on said support including a piston cylinder, a piston member in said cylinder and movable therein between spaced positions, a movable member, and means connecting said movable member to said piston member for movement in relation to said support between spaced positions; means selectively operable from the surface for alternately moving said piston member between its said positions including pressure-developing means connected to said piston cylinder and containing a fluid for developing fluid pressures suflicient to move said movable member between its said positions; and disabling means adapted for response to a predetermined movement of a suspension member connected to said support including normally-closed valve means for relieving the fluid pressure applied to said piston member without loss of said fluid to return said movable member from one of its said positions to the other of its said positions.

18. The Well tool of claim 17 wherein said valve means include: a body having a bore therein; a valve member slidably disposed in said bore for movement therein between first and second positions and having an end portion in one portion of said bore; first and second ports in said body and opening into said one bore portion at spaced locations therein; an annular valve seat sealingly disposed in said one bore portion for sliding movement therein between first and second portions between said spaced port locations and having one face adapted for seating engagement with said end portion of said valve member whenever said valve member is in its said first position; means normally urging said one face of said valve seat 12 into seating engagement with said end portion of said valve member and for shifting said valve seat toward its said second position whenever said valve member is moved toward its said second position; stop means halting said valve seat at its said second position before said valve member has reached its said second position to open fluid communication through said valve seat between said first and second ports; and actuating means adapted for connecting such a suspension member and said valve member to move said valve member from its said first position to its said second position upon predetermined movement of such a suspension member.

19. The well tool of claim 18 further including: third and fourth ports in said body and opening into another portion of said bore at spaced locations therein; sealing means between said valve member and said body providing fluid communication between said third and fourth ports so long as said valve member is in its said first position and blocking such fluid communication whenever said valve member is in its said second position.

20. The well tool of claim 19 wherein said sealing means block fluid communication between said third and fourth ports before said valve member and said valve seat have reached their respective said second positions.

21. The well tool of claim 20 wherein said third and fourth ports are connected between said piston cylinder and said pressure-developing means to provide a normallyopen fluid communication path therebetween only so long as said valve member is in its said first position.

References Cited UNITED STATES PATENTS 3,079,793 3/1963 Le Bus et al 166-l00 X 3,104,712 9/1963 Whitten 166--l00 3,173,500 3/1965 Stuart et al 175-77 3,175,392 3/1965 Tharalson et al l77 X 3,253,654 5/1966 Briggs et al l66100 3,273,659 9/1966 Reynolds 166-100 X DAVID H. BROWN, Primary Examiner.

US. Cl. X.R. 166-100; l7599 mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent: No. :"3 Dated March 9 9 Inventor(s) Harold J. Urbanosky It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 26, delete "as" Column 5, line 33, "The" should read To Column '7, lines 22 and 50 "mmeber" should read member Column 8, line 45, "tiono should read tion Column 9, lines 60-66, delete include: member. "3 Column 9, line 6'7, following "means" insert include: an

enclosed chamber normally at a reduced pressure; normallyclosed valve means between said pressure-developing means and said enclosed chamber; and actuating means connected to said valve means and adapted for connection to a suspension member for opening said valve means upon a predetermined movement of such a suspension member.

SIGNED AND smzu JUN 2 31970 GEAL Amer:

EdwardMFletcherJr. mam 3, mm JR. Auditing Officer eomissione'r 01' We

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