US3565170A

US3565170A - Control apparatus for well tools

Info

Publication number: US3565170A
Authority: US
Inventors: Harold J Urbanosky
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1969-12-12
Filing date: 1969-12-12
Publication date: 1971-02-23
Anticipated expiration: 1988-02-23
Also published as: US3628569A

Abstract

The invention disclosed herein is directed to new and improved control apparatus for selectively operating pressure-actuated well tools. In particular, different embodiments are disclosed of control apparatus for well completion tools and especially adapted for repetitively operating at extreme pressure differentials typically experienced in well bores to selectively extend and retract wall-engaging members on the tools.

Description

United States Patent Inventor Harold J. Urbanosky Houston, Tex.

Appl. No. 884,531

Filed Dec. 12, 1969 Patented Feb. 23, 1971 Assignee Schlumberger Technolgy Corporation New York, N.Y.

CONTROL APPARATUS FOR WELL TOOLS 15 Claims, 6 Drawing Figs.

U.S. Cl 166/212; 166/100; 175/78 rm. Cl E2lb 33/12, .E21b 23/00 Field of Search 166/ 1 00, 212; 175/77, 99, 78

[ 56] References Cited UNITED STATES PATENTS 3,010,517 11/1961 Lanmon I1 1. 166/100 3,385,364 5/1968 Whitten 166/100 3,430,716 3/l969 Urbanosky 175/78 3,430,698 3/1969 Urbanosky 166/100 Primary Examiner-James A. Leppink Attorneys-Ernest R. Archambeau, Jr., William J. Beard, David L. Moseley, Edward M. Roney and William R.

Sherman ABSTRACT: The invention disclosed herein is directed to new and improved control apparatus for selectively operating pressure-actuated well tools. In particular, different embodiments are disclosed of control apparatus for well completion tools and especially adapted for repetitively operating at extreme pressure differentials typically experienced in well bores to selectively extend and retract wall-engaging members on the tools.

CONTROL APPARATUS FOR WELL TOOLS In conducting various well completion and testing operations, certain well tools are selectively operated from the surface by controlling the flow of high-pressure fluids such as a hydraulic fluid in the tool or the well bore fluids exterior of the tool. Typical of such tools are those disclosed in the Brieger US. Pat. No. 2,965,176 and the Whitten U.S. Pat. No. 3,385,364 for obtaining fluid samples from earth formations. With these tools, selectively operable valves are sequentially opened upon command from the surface for controlling either hydraulic fluids or well bore fluids to operate the apparatus. Since tools of this nature are operated only once during a single trip into a well bore, so-called break valves have usually been used heretofore to control the flow of fluids under high pressure-from one passage to another. These break valves are generally comprised of a frangible member blocking a'fluid passage that is cooperatively arranged to fail upon being struck by an explosively impelled hammer. On the other hand, where a well completion tool is to be repetitively operated, the control valves employed therewith (as shown for example at 61 in the Urbanosk'y US. Pat. No. 3,430,698) have typically been operated by solenoid actuators. I-Iereagain, although such solenoid-actuated valves are generally reliable, valvesof this type require a separate electrical conductor in the suspension cable as well as a significant power consumption for satisfactory operation. Moreover, since these solenoid valves must control fluids at extreme pressure differentials, the flow passages therein must be correspondingly small to limit the .physical'dimensions of the solenoid coils to reasonable sizes.

Accordingly, it is an object of the present invention to provide new and improved control apparatus including rcpetitivewithout the sealing member on the valve member ever being unsupported as the valve member is moving between its respective operating positions. To employ this new and imtendible wall-engaging member. The new and improved control apparatus further includes selectively directed pressuredeveloping means connected between the fluid reservoir and each side of the piston member in such a mannerthat, by alternatively connecting the pressure-developing means to one or the other of the twosides of the piston member, the wallengaging member carried thereon will be selectively extended and retracted. To return the wall-engaging member to its usual position, the new and improved valve 'is' connected between one side of the piston member and the fluid reservoir. A selectively controlled actuator for the valve is coupled to the other side of the piston member so that, upon operation of the pressure-developing means to retract the wall engaging member,

7 v the normally closed valve will be opened to exhaust the pressure fluid to the reservoir for returning the piston member to its usual-position.

The novel features of the present invention are set forth with particularity in the appended claims. The invention,

best understood by way of the following description of exemplary apparatus employing the principles of the invention as illustrated in the accompanying drawings, inwhich:

H0. 1 shows a well tool including a wall-engaging member that is selectively operated by the control apparatus of the present invention as this tool will appear in a well bore;

- together with further objects and advantages thereof, may be FIG. 2 is a diagrammatic representation of a tool-anchoring system employing the control apparatus and a valve arranged in accordance withthe present invention;

FIG. 3 is a cross-sectional view of a portion of the tool of FIG. 1 to illustrate a preferred embodiment of a valve for use with the present invention;

FIG. 4 is an enlarged view of a portion of FIG. 3 but showing the valve in its fully. opened position;

FIG. 5 is a further enlarged view of another portion of the valve depicted in FIGS. 3 and 4; and

FIG. 6 is a cross-sectional view similar to that of FIG. 3, but showing an alternate embodiment of a valve also for use with the present invention.

Turning now to FIG. 1, a well completion 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 (riot shown in FIG. 1). As will subsequently be described, the control apparatus 13 of the present invention includes an extendiblewall-engaging anchor 14 which, when extended against one wall of the borehole 11, will urge the forward face of the tool housing 15 against the opposite wall of the borehole and secure the tool 10 in position for operation. g

, Since the tool 10 could just as well be any typical open-hole or cased-hole tool employing one or moreextendible wall-engaging members, as at 14, only a brief description of the tool itself is required to illustrate a typical application of the present invention. Accordingly, the tool 10 depicted is the core-sampling tool fully described in the Urbanosky U.S. Pat. No. 3,430,716 for obtaining one or more elongated formation samples from selected earth formations traversed by the" borehole 11. To accomplish this, the tool 10 includes suitably arranged motive means (not shown) for supporting and driving a pair of similar circular cutting wheels 16 operatively arranged for simultaneous rotation in outwardly converging vertical planes. Means (not shown) are provided in the tool 10 for carrying the cutting wheels 16 upwardly and, as they first move upwardly, extending the rotating wheels through an elongated opening 17 along the forward face of the tool housing 15 to begin cutting their way into the adjacent earth formation 18. Then, upon further upward travel of the cutting wheels 16, an elongated prismatic formation sample 19 will be cut out of the wall of the borehole 11. As the cutting wheels 16 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 17 Once the formation sample 19 is freed, the sample will fall through the housing opening 17 and be collected in thelowermost portion of the housing 15. Additional samples, as at 19, can be successively obtained by retracting the anchoring member 14, repositioning the tool 10 at different locations in the borehole 11, and reextending the wall-engaging member.

Turning now to FIG. 2, a schematic representation is shown of a preferred arrangement of the control apparatus 13. of the present invention. In general, the control apparatus 13 includes a fluid reservoir-20 which is conveniently located in the upper portion of the housing 15. For reasons that will subsequently be explained, the tool housing 15 is divided into upward and

lower sections

21 and 22 that are telescopically fitted together and fluidly sealed in relation to one another by one or more sealing members 23 to normally close the upper end of the reservoir 29. The lower end of the reservoir 20 is closed by a transverse'wall 24 across the housing section 22. A suitable pressure fluid, such as a typical hydraulic oil or the like, is introduced through one or more normally closed filling ports (not shown) in the housing 15 until the reservoir 20 is define therein separate enclosed

chambers

30 and 31 ahead of 5 and behind the pistons.

Pressure-developing means, such as a typical gear pump 32 driven by a reversible electric motor 33, are mounted in the housing and preferably located within the fluid reservoir itself. Since the pump 32 can be selectively driven in alternate directions (as indicated by the

arrows

34 and 35

typical check valves

36 and 37 are connected to the

fluid lines

38 and 39 on each side of the gear pump and respectively arranged to open only to admit fluid from the reservoir 20 to their associated fluid line. Thus, whenever the pump 32 is operating, only one or the other of the

check valves

36 and 37 will be open to admit fluid from the reservoir 20 to either the conduit 38 or the conduit 39 depending, of course, upon which direction (34 or 35) the motor 33 is running.

Accordingly, when the pump 32 is being rotatively driven in the direction indicated by the arrows 34, the conduit 39 will be connected to what is then the suction side of the pump and the check valve 37 will be open to admit fluid from the reservoir 20 through the conduit 39 to the pump. The other conduit 38 will, therefore, then be on the discharge side of the pump 32 and the check valve 36 will remain closed. On the other hand, when the pump 32 is running in the opposite rotational direction 35, it will take suction through the now-open check valve 36 and the conduit 38. The check valve 37 will now be closed, however, since the conduit 39 is then on the high-pressure or discharge side of the pump 32.

The other end of the conduit 39 and its associated connection to the pump 32 are connected by a conduit 40 to the enclosed chambers 30 ahead of the enlarged pistons 26. Thus,

whenever the pump 32 is being driven in the direction shown by the arrows 35, fluid will be taken from the reservoir 20 through the check valve 36 and delivered under pressure by way of the conduit 40 to the forward piston chambers 30. This will, of course, retract the wallengaging member 14.

The other conduit 38 and its associated connection to the pump 32 are connected by a conduit 41 and to the rearward piston chambers 31 preferably by the normally open and common ports of a three-way valve 42 connected in the conduit 41 for reasons that will be subsequently explained. A check valve 43 in the conduit 41 is arranged to permit flow from the pump 32 to the piston chambers 31 by way of the three-way valve 42 but halt flow in the reverse direction back to the pump. As indicated diagrammatically by the unbroken line 44, the threeway valve 42 is arranged to normally permit flow through the conduit 41 to the enclosed piston chambers 31 behind the enlarged pistons 26. Thus, so long as the three-way valve 42 is in its normal operating position shown in H0. 2, whenever the pump 32 is driven in the direction shown by the arrows 34, fluid will be taken from the reservoir 20 through the check valve 37 and delivered under pressure through the conduit 41 and the three-way valve to the rearward piston chambers 31. This will, of course, be effective to forcibly extend the wall-engaging member 14.

it will be appreciated, of course, that steps should be taken to accommodate volumetric changes in the fluid reservoir 20 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, the housing 15 is preferably arranged to provide a supply reservoir 45 between spaced

transverse walls

46 and 47 below the transverse wall 24. A piston member 48 is slidably disposed in the enclosed space 45 and fluidly sealed therein by a sealing member 49. A port 50 is arranged in the wall of the housing 15 to admit borehole fluids below the piston 48 and, since the reservoir 45 above the piston is filled with the hydraulic fluid, the hydraulic fluid in the supply reservoir is maintained at the borehole pressure. in the preferred manner of providing fluid communication between the space 45 and the fluid reservoir 20, a tubular member 51 is extended along the longitudinal axis of the housing 15 through the spaced

transverse walls

24, 46 and 47 and fluidly sealed to each of these walls. One or more lateral ports 52 are provided in the tubular member 51 to allow hydraulic fluid to flow therethrough between the supply reservoir 45 and the fluid reservoir 20. The piston member 48 is, therefore, made annular and is free to move relative to the fixed tubular member 51, with a fluid seal 53 therebetween fluidly sealing the members to one another. As a matter of convenience, the conductors of an electrical cable 54 are brought into the reservoir 20 through suitable conductor seals, as at 55, and passed through the tubular member 51 to various electrical components (not shown) in the lower portions of the tool 10.

Turning now to the operation of the control apparatus 13 of the present invention. The wall-engaging member 14 is, of course, preferably retracted while the tool 10 is being moved to a desired location in the borehole 10. Once it is determined that the wall-engaging member 14 is to be extended, by means of typical circuitry (not shown) at the surface as well as in the tool 10, a suitable source of electrical power (not shown) is connected to the motor 33 by its conductors 33a to drive the pump 32 in the direction indicated by the arrows 34. As the pump 32 is driven in this direction, fluid will be drawn to the pump from both the forward piston chambers 30 and, by way of the check valve 37, from the fluid reservoir 20 as well. The combined fluids will then be pumped on through the conduit 41 and the three-way valve 42 (by way of the normally open path 44 therethrough) into the piston chambers 31 behind the enlarged pistons 26. This will, of course, be effective to move the wall-engaging member 14 outwardly to its extended positron.

Once the wall-engaging member 14 has contacted one wall of the borehole 11 and, as a result, moved the forward face of the tool 10 against the opposite borehole wall (as shown in FIG. 1), continued operation of the pump 32 will, of course, begin increasing the pressure in the rearward piston chambers 31. Since this pressure will continue to increase, means, such as a typical pressure switch 56 connected to the conduit 41, are provided for stopping the pump motor 33 once the pressure in the piston chambers 31 reach a magnitude sufficient to hold the wall-engaging member 14 against the wall of the borehole 11 with a desired force. Thus, by means of the pressure switch 56, the pump 32 will be halted once the pressure in the piston chambers 31 reach the predetermined cutoff setting of the pressure switch. Ordinarily, the pressure in the piston chambers 31 will remain relatively constant once the pump 32 is halted. Should, however, there be leakage of some nature or should the wall-engaging member 14 move further outwardly into, for example, a soft place in the formation 18, the pressure in the piston chambers 31 will decrease. Thus, to maintain the pressure in the piston chambers 31 within a desired range, the pressure switch 56 is also suitably arranged to restart the pump 32 should the pressure in the rearward piston chambers drop below a predetermined pressure. These settings for the pressure switch 56 will, of course, be selected to keep the pressure in the piston chambers 31 at a level calculated to maintain the tool 10 anchored with at least a force sufficient to reliably hold it in position in the borehole 11.

To retract the wall-engaging member 14, the pump 32 is driven in the direction indicated by the arrows 35. Simultaneously with the starting of the motor 33, the control apparatus 13 further includes a new and improved pressure-actuated valve 57 (also connected to the conduit 41) is opened (as will subsequently be explained in detail) to enable fluid in the rearward piston chambers 31 to be drained (by way of the conduit 41 and the valve 42) back to the fluid reservoir 20. The check valve 43 will, of course, prevent this fluid from returning by way of the pump 32. As fluid is forced from the enclosed piston chambers 31, the pump 32 will be simultaneously removing fluid from the fluid reservoir 20 by way of the check valve 36 and pumping it into the forward piston chambers 30 to retract the wall-engaging member 14. Once the wall-engaging member 14 is fully retracted, the pump motor 33 will be stopped and the valve 57 will be reclosed in response to the decrease in pressure. The control apparatus 13 is then again in readiness for repeating the above-described operations. It will be recognized, of course, that any volumetric changes in the reservoir 20 during these operations will be accommodated by movement of the piston 48 within the supply reservoir 45.

The above-described operations willordinarily besuffcient for typical service of the anchoring apparatus 13. It will be appreciated, however, that malfunctions can occur in even the best of well tools. Accordingly, to insure that the wall-engaging member 14 can always be retracted should any portion of the control apparatus 13 fail while the tool is anchored, the hydraulic system is adapted to be disabled in response .to movement of the suspension cable 12.'To accomplish this, an annular piston member 58 is slidably disposed in an annular chamber 59 formed in the housing 15 between the

partitions

24 and 46 around the tubular member 51 and fluidly sealed therein by sealing

members

60 and 61. The piston 58 is initially positioned at the upper end of the chamber 59 and held *there by the friction of the sealing

members

60 and 61. A conduit 62 is connected between the chamber 59 above the piston 58 to the normally closed port of the three-way valve 42. An access port in the housing 15 is provided to provide communication into the chamber 59, with asuitable closure member 63 normally closing the port. a

In the usual case,.the three-way valve 42 will remain close and block communication to the chamber 59 which is initially empty and at atmospheric pressure. It. will be appreciated,

however, that once the three-way valve 42 is shifted to open flow (as shown by the diagrammatic flow path 64) between the common port and normally closed port of the three-way valve, direct communication is established (by way of the conduits 41 and 62) between the rearward piston chambers 31 and the empty chamber 59. Thus, actuation of the three-way valve 42 will be effective to drain the hydraulic fluid in the rearward piston chambers 31 into the empty chamber 59 and reduce the pressure in these piston chambers sufficiently to retract the wall-engaging member 14. To actuate the three way valve 42, an actuating member 65 is connected between the valve and the lower end of the upper housing section 21. It will be appreciated, of course, that the telescoping arrangement of the adjacent ends of the

housing sections

21 and 22 will permit one to move relative to the other within the limits provided by an outwardly directed shoulder 66 on the lower end of the upper housing sectionand spaced below an inwardly directed shoulder 67 on the lower housing section.

Accordingly, should there be a malfunction in the hydraulic system of the control apparatus 13 while the tool 10 is anchored as shown in FIG. 1, the suspension cable 12 will be tensioned sufficiently to fail one or more shear members, as at 68, which ordinarily secure the

housing sections

21 and 22 to one another. Once the shear member 68 fails, the upper housing section 21 will be free to move upwardly in relation to the anchored housing section 22 until the

shoulders

66 and 67 engage. This upward movement will be sufficient to act through the actuating member 65 and shift the three-way valve 42 to its other position to open communication (by way of the path 64) between the piston chambers 31 and the empty chamber 59. lt should be noted that the sealing members 23 will keep the fluid reservoir 20 still sealed. Once the control apparatus 13 has been disabled in this manner, it is, of course, necessary to return the tool 10 to the surface.

From the foregoing description of the control apparatus 13 it will be appreciated that the control valve 57 is especially arranged to remain closed so long as the pump 32 is either not operating or is being driven (in the direction of the arrows 34) to extend the walbengaging member 14. On the other hand, the control valve 57 is adapted to open in response to the pressure developed when the pump 32 is driven in the opposite rotative direction 35 for retracting the anchor member 14. In this manner, by arranging the new and improved control valve 57 to operate only in response to selected operations of the pump 32, the previous practice of employing one or more solenoid-actuated valves is not required with the control apparatus 13 of the present invention.

Accordingly, as best seen in FIG. 3, in a preferred embodiment of the control valve 57, the valve is preferably disposed in a lateral bore 69 arranged in the tool housing 15 and joining an enlarged diameter axially aligned'bore 70. So that access may be conveniently gained to the valve '57, the lateral bores 69 and 70 are extended transversely across the housing 15 and fluidly sealed at their respective op'en outer ends by suitable closure members such as threaded end caps or plugs 71 and 72. Fluid passages 73-75 are suitably formed in the tool housing 15 and terminated at longitudinally spaced intervals along the combined length of the lateral bores 69 and 70. As will subsequently be explained, the first passage 73 terminates near the left-hand end (as viewed in FIG. 3) of the smaller lateral bore 69 and serves as at least a'portion of the pressureactuating conduit 76 schematically represented in F IG. 2, the second passage 74 (which'serves as at least a part of the conduit 41) is terminated near the inner end of the smaller lateral bore, and the third passage 75 provides communication betweenthe enlarged diameter lateral bore 70 and the fluid reservoir 20.

The control valve 57 includes an elongated spool member 77 that is slidably disposed in the smallerlateral bore 69 and has enlarged

diameter end portions

78 and 79 on its opposite ends fluidly sealed therein which respectively serve as a piston actuator and a valve member. As illustrated in FIG. 3, the

.spool member 77 is arranged to normally position the piston actuator 78 a short distance inwardly from the intersection of the first passage 73 with the smaller lateral bore 69 so that, upon an increase of fluid pressure in the first passage, the spool member will be shifted further inwardly (to the right as viewed in the drawings) against biasing means such as a compression spring 80 arranged in the smaller lateral bore and engaged between the enlarged head 78 and an inwardly directed shoulder 81 formed near the right-hand end of the smaller bore. If additional biasing force is required, a second compression spring 82 can also be arranged in the enlarged bore 70 between the head of the valve member 79 and the right-hand closure member 72. ltwill, of course, be appreciated that the

springs

80 and 82 will be effective to return the spool member 77 to its initial or closed position upon a decrease of pressure in the fluid passage 73. V

In the preferred embodiment of the control valve 57 illustrated in FIG. 3, the right-hand closure member 72 is provided with a coaxial extension 83 having .one or more lateral openings 84, with the extension projecting inwardly into the enlarged bore 70 and terminating immediately adjacent to the shoulder 85 defined by the junction of the enlarged bore and the lateral bore 69 to the right of the shoulder 81. A blind coaxial bore 86 is formed in the inwardly projecting extension 83 and, for reasons that will be subsequently explained, receives a plurality of coaxial rings or sleeves 87-89 that are tandemly disposed in the blind bore between the shoulder 85 and the closed outer end of the closure member 72. Biasing means such as a stout compression spring or one or more tandemly disposed Bellville washers 90 are arranged in the blind bore 86 for urging the stacked sleeves 87-89 inwardly against one another and the opposed outwardly facing shoulder 85.

Of particular significance to the present invention, it will be noted that the internal diameter of the several stacked sleeves 87-89 is equal to thatof at least that portion 91 of the smaller lateral bore 69 between the

shoulders

81 and 85. Thus, as depicted in FIG. 3, so long as the spool member 77 is in its illustrated position, the enlarged valve member 79 will be recieved in the inward terminal portion 91 of the lateral bore 69 and a sealing member 92 around the valve member will be seated therein to block fluid communication between the

passages

74 and 75. Similarly, by virtue of a sealing member 93 around the piston member 78, fluid communication will always be blocked between the

passages

73 and 74.

Accordingly, upon movement of the spool member 77 forwardly toward the right-hand closure member 72, the enlarged valve member 79 will be moved from the fixed seat 91 into successive seating engagement within the several coaxial sleeves 8789 as the spool is progressively moved outwardly to the right. To limit the forward travel of the spool member 77 into the coaxial sleeves 87-89, stop means are provided such as a post 94 that is disposed against the outer end of the closure member 72 and extended inwardly therefrom into the blind bore 86 to a position calculated to halt the valve member 79 where its sealing member 92 will be engaged with the outermost or right-hand sleeve when the spool has reached its intended extended or forward position.

As best seen in FlGS. 4 and 5, the coaxial sleeves 8789 are particularly arranged to maintain their opposed ends slightly separated from one another so as to provide a controlled fluid communication path between the

passages

74 and 75 when the valve member 79 is not seated within the fixed valve seat 91. in the preferred manner of maintaining the sleeves 8789 slightly spaced apart, two or more longitudinal projections, as at 95, 96 and 97, of a very minor height are respectively formed on one end. of each of the sleeves and adapted to engage the adjacent end of the next sleeve or the shoulder 85. in this manner, substantially continuous circumferential gaps 98-l00 will be defined between the shoulder 85 and the opposed ends of the several rings 8789. Although the longitudinal spacing of these gaps 98-100 need only be in the order of 0.0001 to 0.005 inch, at the extreme operating pressures normally imposed on the control apparatus 13 sufficient flow rates will be obtained between the

passages

74 and 75 to achieve satisfactory operation. In should be noted that the gaps 98-100 need not be equal. In

fact, it is preferred that the first gap 98 be much smaller than the

other gaps

99 and 100; and, that the last gap be the larger of the three gaps.

Accordingly, of particular significance to the present invention, it will be appreciated that as the valve member 79 is moving between either of its two positions respectively depicted in FIGS, 3 and 4, the sealing member 92 thereon will always be confined within one or more of the several sleeves 8789 so as to effectively support the sealing member against deformation or extrusion by the extreme fluid pressures acting across the sealing member as the valve member opens. Furthermore, the sealing member 92 will be fully supported within the outcrmost sleeve 89 when the valve member 79 is open and also will be supported within the fixed valve seat 91 when the valve member is in its closed position. Accordingly, at no time during the repetitive operation of the control valve 57 will there be a chance that the sealing member 92 will be damaged by the flow of high-pressure fluids between the

passages

74 and 75.

It will be appreciated, of course, that the control valve 57 is best suited for controlling the flow of relatively clean hydraulic fluids in view of the narrowness of the gaps 98-100. Accordingly, an alternate embodiment is depicted in FIG. 6 of a control valve 57 which may also be used with the control apparatus of the present invention that is particularly adapted for controlling the flow of dirty fluids such as well bore or formation fluids. As seen there, the control valve 57 is substantially arranged as the control valve 57 but with the exception that only a single sleeve 89 is disposed in the enlarged bore 70 and adapted to be moved to the right (as viewed in F IG. 6) against the biasing spring 82 as the valve is opened against the biasing spring 80'. Thus, as the valve member 79 is moved toward its open position, once the sealing member 92' thereon is received within the coaxial sleeve 89', further movement of the spool 77' will progressively open the circumferential gap between the rear of the sleeve and the forwardly facing shoulder 85. This progressive opening of this circumferential gap will, of course, accommodate a correspondingly greater flow of fluids between the passages 74' and 75' without endangering the integrity of the seal 92 which is, by this time, safely supported within the movable valve seat or coaxial sleeve 89'. Closure of the valve 57' can, of course, be readily accomplished by simply reducing the pressure in the passage 73 so that the springs and 82 will return the valve spool 77 to its initial position.

Accordingly, it will be appreciated that the present invention has provided new and improved control apparatus for well tools in which a movable wall-engaging member is to be repetitively extended and retracted. By coupling the wall-engaging member to a piston actuator that is controlled by a selectively directed fluid pump, the pump may be operated to withdraw a motivating fluid from a suitable reservoir for moving the piston in one direction. Thereafter, to return the piston and the wall-engaging member, the fluid pump may be reversed and, by means of either of the two disclosed pressureresponsive control valves, the pressured motivating fluid will be simply discharged back into the reservoir without requiring the electrically operated valves. Moreover, by virtue of the particular design of the disclosed valves with spaced valve seats for supporting the member of the moving valve member as it moves between its open and closed positions, potential damage to the sealing member will be eliminated to permit reliable repetitive operation of the control apparatus of the present invention.

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.

lclaim:

1. A well tool adapted for suspension in a well bore and comprising: a support; a wall-engaging member operatively mounted on said support for movement relative thereto between extended and retracted positions; a piston cylinder on said support; a piston member operatively arranged for movement back and forth in said cylinder defining forward and rearward enclosed spaces therein and coupled to said wall-engaging member for moving said wall-engaging member back and forth between its said positions upon the admission of pressured fluids alternately into said enclosed spaces; and control means on said support. including an enclosed fluid reservoir, pressure-developing means selectively operable from the surface and operatively coupled between said reservoir and said enclosed spaces for alternatively supplying pressured fluids from said reservoir to said enclosed spaces for moving said wall-engaging member back and forth between its said positions, and valve means coupled between one of said enclosed spaces and said reservoir and responsive to an increase of fluid pressure in the other of said enclosed spaces by said pressure-developing means for exhausting pressured fluids from said one enclosed space back to said reservoir as pressured fluids are supplied by said pressure-developing means to said other enclosed space.

2. The well tool of claim 1 further including second valve means operatively coupled between said pressure-developing means and said one enclosed space for retaining fluids supplied thereto in said one enclosed space until said first-mentioned valve means exhaust fluids from said one enclosed space.

3. The well tool of claim 1 wherein said one enclosed space is said rearward space so that, upon delivery of pressured fluids to said forward space, said valve means will exhaust pressured fluids from said rearward space to allow corresponding rearward movement of said piston member.

4. The well tool of claim 1 wherein said pressure-developing means include reversible fluid-pumping means, selectivelyreversible motor means coupled to said fluid-pumping means and operable from the surface for alternately driving said fluid-pumping means in opposite directions, and conduit means operatively coupling said fluid-pumping means to said reservoir and each of said enclosed spaces.

5. The well too] of claim 4 wherein said one enclosed space is said rearward space so that, upon delivery of pressured fluids to said forward space, said valve means will exhaust pressured fluids from said rearward space to allow corresponding rearward movement of said piston member.

6. The well tool of claim 1 wherein said valve means include pressure-responsive actuating means operatively coupled to said other enclosed space for operating said valve means only upon selected increases of fluid pressure in said other enclosed space.

7. The well tool of claim 1 wherein said wall-engaging member is adapted foranchoring said well tool in a well bore upon movement of said wall-engaging member to its said extended position. v a.

8. The well tool of claim 1 wherein said valve means include a valve body having a longitudinalbore', a valve member in said valve body adapted for movementin said longitudinal bore between a normal closed positionand an open position, pressure-responsiveactuating means coupled between said other enclosed space and said valvemember and adapted for moving said valve member to its said open position upon an increase in said other enclosed space, and seating means in said longitudinal bore operatively supporting said valve member upon its movement between its said positions and providing increasing fluid communication between said one enclosed space and said reservoir in proportion to the extent of movement of said valve member toward its said open position.

9. The well tool of claim 8 wherein said seating means are comprised of a first valve seat in said longitudinal bore coaxially receiving said valve member whenever said valve member is in its said closed position and a second valve seat including a plurality of tubular members tandemly disposed along said longitudinal bore for successively receiving said valve member whenever said valve member is moved from its said closed position toward its said open position.

'10. The well tool of claim 8 wherein said seating means are comprised of a first valve seat in said longitudinal bore coaxially receiving said valve member whenever said valve member is in its said closed position and a second valve seat including a tubular member movably disposed in said longitudinal bore adjacent to said first valve seat for coaxially receiving said valve member is moved from its said closed position and being shifted thereby along said longitudinal bore as said valve member is moved toward its said open-position. 1

11. A wei tool adapted for suspension in a well bore and comprising: a body; a wall-engaging member operatively mounted on said body for lateralmo've'ment relative thereto between extended and retracted positions; piston means operatively arranged between bodyand said wall-engaging member including a piston cylinder and a piston member means for operating said piston means and including an enclosed fluid reservoir on said body, selectively reversible fluidpumping means in fluid communication with said reservoir and selectively operable from the surface for alternatively pumping fluids therefrom into said chambers, means including first conduit means coupling said fluid-pumping means to one of said chambers and first valve means for retaining therein fluids pumped into said one chamber, second conduit means coupling said fluid-pumping means to the other of said chambers, and second valve means coupled between said one chamber and said reservoir and operable upon an increase of fluid pressure in said other chamber for discharging fluids from said one chamber back into said reservoir.

12. The well tool of claim ll wherein said wall-engaging member is adapted to anchor said well tool in a well bore upon movement of said wall-engaging'me'mber to its said extended position. v

13. The well too] of claim 11 wherein said second valve means include a valve body having a longitudinal bore, a valve member in said valve body and adapted for movement in said longitudinal bore between a normally closed position and an open position, pressure-responsive actuating means coupled between said other chamber and said valve member and adapted for moving said valve member to its said open position upon an increase of fluid pressure in'said other chamber and seating means in said longitudinal bore supporting sai valve member upon its movement between its said positions.

14. The well tool of claim 13 wherein said valve member includes a sealing member mounted therearound and said seating means operatively support .said sealing member upon movement of said valve member between its said positions.

15. The well tool of claim 13 wherein said seating means include passage means therein for increasing fluid communication between said one chamber and said reservoir in proportion to the extent of movement of 'said valve member toward its said open position.

Claims

1. A well tool adapted for suspension in a well bore and comprising: a support; a wall-engaging member operatively mounted on said support for movement relative thereto between extended and retracted positions; a piston cylinder on said support; a piston member operatively arranged for movement back and forth in said cylinder defining forward and rearward enclosed spaces therein and coupled to said wall-engaging member for moving said wall-engaging member back and forth between its said positions upon the admission of pressured fluids alternately into said enclosed spaces; and control means on said support including an enclosed fluid reservoir, pressure-developing means selectively operable from the surface and operatively coupled between said reservoir and said enclosed spaces for alternatively supplying pressured fluids from said reservoir to said enclosed spaces for moving said wall-engaging member back and forth between its said positions, and valve means coupled between one of said enclosed spaces and said reservoir and responsive to an increase of fluid pressure in the other of said enclosed spaces by said pressuredeveloping means for exhausting pressured fluids from said one enclosed space back to said reservoir as pressured fluids are supplied by said pressure-developing means to said other enclosed space.

4. The well tool of claim 1 wherein said pressure-developing means include reversible fluid-pumping means, selectively-reversible motor means coupled to said fluid-pumping means and operable from the surface for alternately driving said fluid-pumping means in opposite directions, and conduit means operatively coupling said fluid-pumping means to said reservoir and each of said enclosed spaces.

5. The well tool of claim 4 wherein said one enclosed space is said rearward space so that, upon delivery of pressured fluids to said forward space, said valve means will exhaust pressured fluids from said rearward space to allow corresponding rearward movement of said piston member.

7. The well tool of claim 1 wherein said wall-engaging member is adapted for anchoring said well tool in a well bore upon movement of said wall-engaging mEmber to its said extended position.

8. The well tool of claim 1 wherein said valve means include a valve body having a longitudinal bore, a valve member in said valve body adapted for movement in said longitudinal bore between a normal closed position and an open position, pressure-responsive actuating means coupled between said other enclosed space and said valve member and adapted for moving said valve member to its said open position upon an increase in said other enclosed space, and seating means in said longitudinal bore operatively supporting said valve member upon its movement between its said positions and providing increasing fluid communication between said one enclosed space and said reservoir in proportion to the extent of movement of said valve member toward its said open position.

10. The well tool of claim 8 wherein said seating means are comprised of a first valve seat in said longitudinal bore coaxially receiving said valve member whenever said valve member is in its said closed position and a second valve seat including a tubular member movably disposed in said longitudinal bore adjacent to said first valve seat for coaxially receiving said valve member is moved from its said closed position and being shifted thereby along said longitudinal bore as said valve member is moved toward its said open position.

11. A well tool adapted for suspension in a well bore and comprising: a body; a wall-engaging member operatively mounted on said body for lateral movement relative thereto between extended and retracted positions; piston means operatively arranged between said body and said wall-engaging member including a piston cylinder and a piston member movably disposed therein defining first and second chambers on opposite sides of said piston member adapted to alternately receive selectively admitted pressure fluids for moving said wall-engaging member between its said positions; and control means for operating said piston means and including an enclosed fluid reservoir on said body, selectively reversible fluid-pumping means in fluid communication with said reservoir and selectively operable from the surface for alternatively pumping fluids therefrom into said chambers, means including first conduit means coupling said fluid-pumping means to one of said chambers and first valve means for retaining therein fluids pumped into said one chamber, second conduit means coupling said fluid-pumping means to the other of said chambers, and second valve means coupled between said one chamber and said reservoir and operable upon an increase of fluid pressure in said other chamber for discharging fluids from said one chamber back into said reservoir.

12. The well tool of claim 11 wherein said wall-engaging member is adapted to anchor said well tool in a well bore upon movement of said wall-engaging member to its said extended position.

13. The well tool of claim 11 wherein said second valve means include a valve body having a longitudinal bore, a valve member in said valve body and adapted for movement in said longitudinal bore between a normally closed position and an open position, pressure-responsive actuating means coupled between said other chamber and said valve member and adapted for moving said valve member to its said open position upon an increase of fluid pressure in said other chamber, and seating means in said longitudinal bore supporting said valve member upon its movement between its said positions.

14. The well tool of claim 13 wherein said valve member includes a sealing member mouNted therearound and said seating means operatively support said sealing member upon movement of said valve member between its said positions.

15. The well tool of claim 13 wherein said seating means include passage means therein for increasing fluid communication between said one chamber and said reservoir in proportion to the extent of movement of said valve member toward its said open position.