US3329208A

US3329208A - Control valve for well tools

Info

Publication number: US3329208A
Application number: US472148A
Authority: US
Inventors: Ulrich E Voetter
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1965-07-15
Filing date: 1965-07-15
Publication date: 1967-07-04
Anticipated expiration: 1984-07-04

Description

y 4, 1957 u. E. VOETTER CONTROL VALVE FOR WELL TUOLS 2 Sheets-Sheet 1.

Filed July 15, 1965 r em W 1 am V f 0 C N u United States Patent 3,329,208 CONTROL VALVE FOR WELL TOOLS Ulrich E. Voetter, Houston, Tex., assignor to Schlumberger Technology Corporation, Houston, Tex., a corporation of Texas Filed July 15, 1965, Ser. No. 472,148 4 Claims. (Cl. 16663) This invention relates to new and improved control apparatus for Well tools; and, more particularly, to surface-actuated valves for controlling well tools employed for conducting various operations in a well bore.

In conducting various well completion and testing operations, certain well tools require the selective control from the surface of the flow of a fluid such as a hydraulic fluid in the tool or a fluid exterior of the tool. Typical of such tools are those disclosed in the Brieger Patent No. 2,965,176; the Whitten Patent No. 3,104,712; or in an application by Whitten, Ser. No. 384,924, filed July 13, 1964, now US. Patent No. 3,299,953, for obtaining fluid samples from earth formations. The tools disclosed there include one or more sample-admitting means including elastomeric sealing members mounted along one side of the tool that are arranged to be sealingly engaged with one wall of a borehole. Upon command from the surface, a selectively operable valve is opened to admit well control fluids into the tool where, by means of a piston, a hydraulic pressure greater than the hydrostatic pressure of the well control fluids is developed for actuating the apparatus. Once the hydraulic system has been actuated, extendible wall-engaging means on the opposite side of the tool shift it laterally to scaling engage the sealing members against an exposed formation face. Once the sealing members have been engaged, fluid communication is established between the formation and sampleadmitting means on the tool. Then, upon command from the surface, a second selectively operable valve in the tool is opened to admit whatever recoverable connate fluids there may be in the adjacent formation. Once this second valve has opened, a discrete volume of these connate fluids is expelled by the formation pressure through the sample-admitting means and into a low-pressure samplereceiving chamber on the tool. After it is believed that an adequate fluid sample has been obtained, another valve in the tool is actuated to close the sample-receiving chamber. Thereafter, upon actuation of still another valve, the extendible wall-engaging member is retracted to permit retrieval of the tool for examination of the fluid sample.

Although these and other similar tools have been generally successful, there are still some problems encountered controlling the flow of fluids therein. Heretofore, socalled break valves have often been used to control the flow of fluids under high pressures 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. Although such break valves have been satisfactory, there have been occasions, however, where a malfunction in their operation has resulted in an unsuccessful operation.

One embodiment of a typical break valve, such as shown at 60 (Fig. 2) in the aforementioned Brieger patent, is comprised of a hollowed plug that is sealed in one fluid passage and has a weakened end portion extending into an intersecting passage adjacent to an explosive- 1y propelled hammer. Upon detonation of a small explosive charge behind the hammer, the hammer is impelled against the free end of the plug with suflicient force to shear the weakened portion and expose the hollow interior of the plug. Similarly, another typical break valve, such as that shown at 144 (Fig. 7) of the same patent, is comprised of a hollowed plug having a weakened end wall blocking the passage in which the plug is disposed. An explosively propelled hammer is loosely coupled to the weakened end wall and arranged, upon detonation of an eX-posive charge therebehind, to drive the end wall inwardly with suflicient force to shear out a portion thereof and open fluid communication.

Although they have been successfully used in countless operations a number of unsuccessful operations have been attributed to malfunctions of such break valves from one or more of several causes. For example, with these valves, it is essential that the explosive charge develops a substantial pressure for the hammer to be impelled with suflicient force to fracture the frangible member. Thus, should the powder be even partially defective, the barrier may not be opened and a misrun may result. It is also essential that the explosive igniter in each of these valves remain tightly sealed long enough for the explosive to develop sufficient pressure to actuate the valve properly. Thus, should the igniter instead be prematurely blown out of its position, the valve will not be opened. It will be appreciated that even if expulsion of the igniter admits well control fluids into the explosive chamber, the hydrostatic pres-sure is not suflicient to fracture the frangible member.

Moreover, in each of these valves, there is always the possibility that a broken portion of the frangible barrier will partially or totally plug a flow passage. For example, in the first-described embodiment (Fig. 2 in the Brieger patent), the end portion 62 of valve is broken off upon impact of the hammer 55. This freed end portion 62 can easily become lodged within one of the flow passages so as to at least greatly restrict the flow of fluid therethrough. Similarly, in the valve 144 in Fig. 7 of the Brieger patent, both the annular and sheared-out portions of the cap 152 are intended to be displaced into bore 149 so as to clear the entrance to the lateral passage 163. Such a position would clearly present a substantial obstruction of flow of fluid.

It will also be recognized that should some of the broken portions of these valves become lodged in a fluid sample passage, loose formation materials swept in with the conn'ate fluids will tend to accumulate in pockets formed by the broken portions and, quite possibly, plug the flow line.

Accordingly, it is an object of the present invention to provide new and improved explosively actuated control valves that are reliably opened against the extreme pressures normally encountered in a borehole and then held in a full-open position by these external pressures.

This and other objects of the present invention are provided by employing a valve structure in which an explosive material is detonated to expel a closure member from the valve member for first admitting explosive gases into a low-pressure actuating chamber for moving the valve member toward an open position and then subsequently admitting fluids at a higher pressure exterior of the valve into the chamber for holding the valve member open and, if necessary, for moving the valve member to its open position.

The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of 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:

FIG. 1 depicts typical sample-taking apparatus in which one or more valves of the present invention may be em ployed as it might appear within a borehole;

FIG. 2 is a simplified, schematic representation of the sample-taking apparatu illustrated in FIG. 1;

FIG. 3 is a cross-sectional view in elevation of a portion of the apparatus of FIG. 1 to illustrate one manner in which a valve arranged in accordance with the present invention may be employed;

FIG. 4 is a view similar to FIG. 3 but showing the valve in its fully opened position; and

FIG. 5 is a cross-sectional view similar to that of FIG. 3, but showing an alternate embodiment of a valve em ploying the principles of the present invention.

Turning now to FIG. 1, fluid-sampling apparatus 10, including one or more valves of the present invention, is shown suspended from a multi-conductor cable 11 and positioned in a borehole 12 containing well control fluids adjacent to an earth formation 13 for collecting a sample of connate fluids therefrom. The cable 11 is spooled from a winch 14 at the earths surface, with some of its conductors being connected to a switch 15 for selective con nection to a conventional power supply 16 and others being connected to conventional indicating-and-recording apparatus 17.

The fluid-sampling apparatus is comprised of an elongated body 18 which, to facilitate manufacture and assembly, may be arranged in tandemly connected sections. Longitudinally spaced sample-admitting means including sealing

members

19 and 20 are mounted along one side of the body 18 and extendible wall-engaging means 21 are mounted on the opposite side. In the position illustrated in FIG. 1, the wall-engaging means 21 have been extended to laterally shift the fluid-sampling apparatus 10 in the borehole 12 and sealingly engage the sealing

member

19, 20 with the adjacent exposed face of the formation 13 in readiness for obtaining a sample of connate fluids.

Inasmuch as the particular details of the various components are not necessary for a full understanding of the present invention, the fluid-sampling apparatus 10 is shown only schematically in FIG. 2 to illustrate various roles that the valves of the present invention may play in the operation of such apparatus as well as their relation to the other components therein. Accordingly, these other components may well be those described in greater detail in the aforementioned Whitten application and Brieger and Whitten patents; and their descriptions will therefore be limited to only that necessary for understanding their basic operation and general relation to one another and to the present invention.

As illustrated in FIG. 2, the fluid-sampling apparatus 10 is basically comprised of a hydraulic system 22 that utilizes the hydrostatic pressure of the well control fluids to develop an increased hydraulic pressure for actuating the apparatus; one or more sample-admitting means such as at 23 and 24; and a sample-collecting system 25 for obtaining a sample of connate fluids.

After the apparatus 10 has been positioned adjacent the formation 14, the hydraulic system 22 is activated from the surface. Wall-engaging means 21 are extended to laterally shift the apparatus 10 and sealingly engage the

annular sealing members

19 and 20 against the exposed face of the formation 13 for obtaining a fluid sample. Once the sample has been collected in the sample-collecting system 25, the pressure in the hydraulic system 22 is relieved to disengage the wall-engaging means 21 and sample-admitting

means

23 and 24 for retrieval of the apparatus 10.

The hydraulic system 22 may be generally arranged as described in Patent No. 3,011,554, granted to Robert Desbrandes, and includes a master piston 26 slidably mounted in a stepped cylinder 27 in the body 18. An electrically initiated, explosively actuated mud valve 28 such as one arranged in accordance with the principles of the present invention, is selectively operable to admit the well control fluids through a passage 29 and into an enlarged-diameter portion 30 of the cylinder 27 above the piston 26. Thus, whenever the mud valve 28 is opened, the hydrostatic pressure of the well control fluids will drive the master piston 26 inwardly to develop a somewhat greater hydraulic pressure in a reduced-diameter portion 31 of the cylinder 27 below the piston. This developed hydraulic pressure will, of course, be equal to the product of the hydrostatic pressure multiplied by the ratio of the areas of the enlarged end 32 and the reduced end 33 of the piston 26.

A pressure-regulating valve 34 (such as the one shown in Figs. 8 and 8a of the Desbrandes patent) responds to the hydrostatic pressure of the well control fluids to maintain the hydraulic pressure of an outlet conduit 35 downstream of the valve 34 at a predetermined differential above the hydrostatic pressure.

The hydraulic system 22 also includes a hydraulic fluid dump chamber 36 connected by a conduit 37 to a hydraulic actuator 38 of a normally-closed, pressure-equalizing valve 39 (such as at in Fig. 5a of Patent No. 3,104,712) and, via a conduit 40 and a normally-closed, electrically initiated, explosively actuated valve 41 that may be arranged in accordance with the invention, to the main hydraulic conduit 35. Dump chamber 36 is normally at atmospheric pressure and is divided into large and

small compartments

42 and 43 by a partition 44 in which an orifice 45 is mounted. When it is desired to retrieve the apparatus 10, the explosively actuated valve 41 is opened to admit hydraulic fluid from the main conduit 35 into the smaller compartment 43 of the dump chamber 36 and, via conduit 37, to the actuator piston 38 of the pressureequalizing valve 39. Although the hydraulic pressure in the main conduit 35 is immediately reduced somewhat when valve 41 is opened, the lower compartment 43 and orifice 45 are suitably sized to enable the hydraulic actuator 38 to open the equalizing valve 39 before the hydraulic pressure drops to its final level.

Pressure-equalizing valve 39 is actuated by the actuator piston 38 which is slidably received within an enlarged- -diameter portion of a stepped cylinder 46. The reduceddiameter portion of the cylinder 46 receives the slidable pressure-equalizing valve 39 which has a rearwardly extending projection 47 that is normally engaged against the forward face of the actuator piston 38. In its normal position as illustrated in FIG. 2, the valve member 39 bloclas fluid communication between a conduit 48 leading to the sample-admitting

means

23 and 24 and conduit 49 opening to the exterior of the apparatus 10. Thus, it will be appreciated, that whenever hydraulic fluid is admitted through valve 41 to the dump chamber 36, the actuator piston 38 will shift the equalizing valve 35 outwardly to open fluid communication between

conduits

48 and 49.

The extendible wall-engaging means 21 on the opposite side of the body 18 from the sampleaadmitting means 23 and 24 is arranged to shift the apparatus 10 laterally in a borehole prior to taking fluid samples. The hydraulically actuated wall-engaging means 21 may be arranged as generally shown at 23 in Fig. 5a of Patent No. 3,104,712, and is comprised of an extendible backup shoe 50 that is normally held in a retracted position by springs 51 against the body 18. A piston actuator 52 is slidably received within a hydraulic cylinder 53 connected by conduit 54 to the main hydraulic conduit 35. Thus, whenever the mud valve 28 is opened, the increased pressure in the main hydraulic conduit 35 will urge the piston actuator 52 outwardly to extend the backup shoe 50 against the adjacent exposed face of the formation.

Although two different types of sampleadmitting means 23 and 24 have been shown in FIG. 2 to illustrate typical embodiments of such sample-admitting means, it will be understood that any one or combination of sampleadmitting means described in the aforementioned patents may be employed with equal success with the valves of the present invention. The sample-admitting

means

23 and 24 include longitudinally spaced

lateral chambers

55 and 56 within the body 18, with the chambers being open at one end and having the annular,

elastomeric sealing members

19 and 20 mounted outside of the body around these openings to provide

central openings

57 and 58 for admitting fluid samples into the chambers. The

chambers

55 and 56 are interconnected by a conduit 59 and, via a normally-closed, electrically initiated explosively actuated valve 60 that may be arranged in accordance with the present invention and a conduit 61 to the sample-collecting system 25.

As described in greater detail in the aforementioned Whitten application, a shaped charge 62 is disposed in the rear of the upper chamber 55. The shaped charge 62 is connected to electrically responsive detonator means, such as a detonating cord 63 and blasting cap 64, that are ignitable from the surface of the ground via a conductor 64a in the cable 11. A first thin-walled closure member 65 is mounted in front of the shaped charge 62 to fluidly seal the shaped charge Within the rearward portion of the chamber 55. A second thin-Walled closure member 66 is disposed ahead of the first member 65 and blocks the central opening 57 through the annular sealing member 19. Thus, it will be appreciated that so long as it has not been detonated, the shaped charge 62 will be isolated by

closure members

65 and 66 from the sample-collecting system and fluids can enter only by way of the other sampleadmitting means 24.

The sample-admitting means 24 in the lower chamber 56 include an actuator piston 67 that is sealingly and slidably mounted in the rear of the chamber and adapted to urge a tubular probe 68 forwardly through the central opening 58 through the sealing member 20. This snorkel tube 68 may, for example, be generally arranged as shown in Fig. 3 of the aforementioned Whitten application. Thus, fluids must pass through the open forward end of the snorkel tube 68 and can enter the chamber 56 only by way of a lateral port 69 in the tube. For delaying the operation of the sample-admitting means 24 until the wallengaging means 21 has shifted the apparatus 10 against the formation, a conduit 70 having an orifice 71 therein connects the main hydraulic conduit 35 to the enclosed space behind the actuator piston 67 at the rear of the chamber 56.

The sample-collecting system 25 includes a samplereceiving chamber 72 which has a normally-open, hydraulically actuated, closure or seal valve 73 (such as shown in Fig. 10 of the aforementioned Desbrandes patent). The seal valve 73 is comprised of a slidable actuator piston 74 in a cylinder 75 that carries a valve member 76 adapted to be seated in a complementary valve seat 77 at the entrance of the sample-receiving chamber 72 to block flow communication with the main fluid conduit 61. The seal valve 73 is normally held open, but once it has been actuated, it will become latched in a closed position. A normally closed, electrically initiated, explosively actuated valve 78 that may be arranged in accordance with the principles of the present invention connects the upper portion of the cylinder 75 to the main hydraulic conduit 35. Thus, to shut off fluid flow from the main fluid conduit 61, the valve 78 is opened to admit hydraulic fluid into the cylinder 75 above piston 74 and shift the valve member 76 into sealing engagement with the valve seat 77.

The sample-receiving chamber 72 generally includes upper and

lower compartments

79 and 80 separated by a partition 81 having a flow restriction or orifice 82. A liquid cushion, such as water 83, in the upper compartment 79 is isolated from the upper portion thereof by a floating piston 84. Since the lower compartment is initially empty, connate fluids entering the upper compartment 79 from the conduit 61 move the piston 84 downwardly at a rate regulated by the flow of the water cushion 83 through the orifice 82.

Pressure transducers

85 and 86 are provided to continuously monitor the pressures in the hydraulic system 22 and sample-collecting system 25. These

transducers

85 and 86 may, for example, be of the type shown in Fig. 9 of the Desbrandes patent and are connected by cable conductors 85a and 86a to the pressure indicating-andrecording apparatus 17 (FIG. 1) at the surface of the earth. Thus, by observing the variations in these pressure measurements, an operator will be advised of each step in the operating cycle of the fluid-sampling apparatus 10.

To operate the sample-taking apparatus 10 illustrated in FIGS. 1 and 2, the apparatus is positioned in a borehole 12 adjacent a particular formation 13. Then, by connecting the power source 16 through switch 15 to the cable conductor 28a, the mud valve 28 will be opened to admit well control fluids from the passage 29 into the upper portion 30 of the master cylinder 27. This will drive the master piston 26 downwardly to develop a substantially greater hydraulic pressure in the reduced-diameter portion 31 of the cylinder 27. The pressure-regulating valve 34 will operate to admit hydraulic fluid into the hydraulic conduit 35 and maintain the pressure therein at a substantially constant differential above the hydrostatic pressure of the well control fluids.

Since the other normally-closed

valves

41 and 78 are not yet opened, the hydraulic fluid will be admitted initially only through conduits 54 and 70 leading to the wallengaging means 21 and the sample-admitting means 24, respectively. However, in view of the restrictive eflect of the orifice 71 in conduit 70, the piston actuator 52 will operate first and extend the backup shoe 50 against the one face of the borehole 12 to shift the apparatus 10 laterally in the opposite direction. Then, once the apparatus 10 has been shifted laterally, the

annular sealing members

19 and 20 will be sealingly engaged against the adjacent face of the formation 13.

Once the hydraulic pressure in the conduit 70 downstream of the orifice 71 has risen above the hydrostatic pressure, the actuator piston 67 will move outwardly to urge the forward end of the snorkel tube 68 against the formation 13. Thus, it will be appreciated that the orifice 71 will delay the operation of the sample-admitting means 24 until the sealing

members

19 and 20 are sealingly engaged against the exposed face of the formation 13. It will be understood also that by monitoring pressure transducer 85, the operator can determine when the sealing

members

19 and 20 have been fully engaged.

Once the hydraulic pressure behind piston 67 has built up to a suflicient magnitude to extend the snorkel tube 68 through the central opening 58 of the sealingmember 20,.

its forward end will be engaged against the formation 13.

Should there be a recoverable and flowable connate fluid,

therein and the formation 13 be unconsolidated, upon opening of the flow-line valve 60, the sample tube 68 will be forced by the hydraulic pressure into the formation as the fluids and loose formation particles flow into the tube. Should, however, the formation 13 be so well consolidated that no particles are washed away, the forward end of the tube 68 will still remain against the formation to conduct the connate fluids into the main fluid conduit 61. It should be noted that although well control fluids will enter the sample-admitting means 24 before it is actuated, their total volume will be known. Thus, since this known volume of fluids is so small relative to the volume of the chamber, their negligible effect can be corrected. when analyzing the trapped connate fluids.

It will be appreciated, of course, that when the flow-line valve 60 first opens, the pressure in the main fluid conduit 61 will be immediately reduced. Then, as the samplereceiving chamber 72 fills, the pressure in the conduit 61 will approach formation pressure. Thus, by monitoring pressure transducer 86, an operator can determine that the flow-line valve 60 has opened as well as when the sample-receiving chamber 72 has filled.

Should there be little or no fluid sample collected by sample-admitting means 24, the operator will then connect the power switch 15 to cable conductor 64a to detonate the shaped charge 62 of the alternate sampleadmitting means 23. Upon detonation of the shaped charge 62, the thin-

Walled closure members

65 and 66 will be punctured and the perforating jet will produce a perforation in the formation 13. Accordingly, should there be recoverable connate fluids that flow into the resultant perforation, they will enter sample-admitting means 23 and flow into the sample-receiving chamber 72 by way of

conduits

59 and 61.

Whenever pressure measurements indicate that the sample-collecting chamber 72 is most likely full, the power switch is connected to cable conductor 78a to open valve 78. Opening of the valve 78 will admit hydraulic fluid from the main conduit 35 to actuate the piston actuator 74 of the seal valve .73 to close off the sample-receiving chamber 72.

To recover the apparatus 10, the power switch 15 is then connected to conductor 41a to open valve 41 to relieve the hydraulic pressure holding the wall-engaging means 21 in extended position. Opening of valve 41 will admit hydraulic fluid to the lower compartment 43 of the dump chamber 36 as well as to the rear of cylinder 46 behind the piston actuator 38 for the pressure-equalizing valve 39. As previously explained, however, the hydraulic pressure in conduit 37 will decrease slowly to enable the actuator 38 to shift the equalizing valve 39 outwardly from its flow-blocking position between

conduits

48 and 49. Once the well control fluids are admitted from conduit 49 into the

sample chambers

55 and 56, fluid pressure across the sealing members 19 and 20' will be equalized. Finally, as the hydraulic pressure drops in the main conduit 35, the hydrostatic pressure of the well control fluids will, with the assistance of springs 51, retract the backup shoe 50 to free the apparatus 10 and allow it to be retrieved.

Turning now to FIG. 3, a partial cross-sectional view in elevation is shown of a portion of the body 18 and a preferred embodiment of a control valve 100' arranged in accordance with the present invention as it, by way of illustration, would be employed in the sample-taking apparatus 10 already described.

T receive the valve 100, a stepped cylindrical bore is formed in the body 18 with a forward reduced-diameter portion 101 and .a rearward, enlarged-diameter portion 102 that opens to the exterior of the body of the fluidsampling apparatus 10. A cylindrical sleeve 103 having a forward end wall 104 with a concentric reduced-diameter bore 105 therethrough is snugly fitted within the enlarged-diameter bore portion 102, with the forward face 106 of the end wall being engaged with the outwardly facing shoulder 107 formed at the junction of the stepped

bore portion

101 and 102. Sealing means, such as an O-ring 108 around the sleeve 103 fluidly seal the sleeve within the enlarged bore portion 102.

A valve member 109 having an enlarged-diameter central portion 110 is slidably mounted within the sleeve 103, with the reduced-diameter forward portion 111 of the member projecting through the internal bore 105 in the forward end wall 104 and its reduced-diameter rearward portion 112 extending beyond the rearward end of the sleeve. The outer end of the enlarged bore portion 102 in the body 18 is closed by an externally threaded annular plug 113 that is snugly fitted over the reduceddiameter rearward portion 112 of the valve member 109. O-

rings

114 and 115 around the exterior and interior of the annular plug 113, respectively, fluidly seal the plug to the body 18 and rearward portion 112 of the valve member 109. -O-rings 116 and 117, respectively, fluidly seal the reduced forward portion 111 of the valve memher 109 within the bore through the sleeve end wall 104 and the enlarged valve member portion within the enlarged diameter bore 118 of the sleeve 103. Thus, it will be appreciated that O-rings 108 and 114-117 form separate fluid-

tight chambers

119 and 120 within the enlarged bore 118 of the sleeve 103 on opposite ends of the valve members enlarged-diarneter central portion 110.

Although their particular arrangement will depend upon the position of the valve 100 in the body 18, inlet and

outlet passages

121 and 122 may be located as shown in FIG. 3. As illustrated there, the inlet passage 121 is coincidentally aligned with the

bore portions

101 and 102 and valve member 109. The outlet passage 122 extends laterally from the reduced diameter bore portion 101.

The mouth of the inlet passage 121 is counterbored to provide a concentric valve seat 123 that is suitably sized to receive a valve head 124 extending from the reduced forward portion 111 of the valve member 109. An O-ring 125 is arranged around the valve head 124 to fluidly seal the valve head within its cooperative seat 123 whenever the valve member 109 is in its forward flow-blocking position as illustrated in FIG. 3.

To facilitate manufacture and assembly, the valve head 124 is preferably threadedly secured to an axial projection 126 on the forward end of the valve member 109. An enlarged flange 127 on the valve head 124 is arranged to engage the end wall 128 of the reduced-diameter bore portion 101 to stop the valve member 109 in its forwardmost position. It will be noted that the enlarged flange 127 on the valve head 125 is arranged to position the valve member 109 as shown to leave the opposed surfaces at opposite ends of the chamber 119 at least slightly separated from one another.

The interior of the valve member 109 is hollowed to provide an enlarged powder chamber 129 that is closed at its forward end and extends generally longitudinally toward the rear of the valve member to an enlarged socket 130 counterbored into the rearwardmost end of the valve member. To provide communication from the powder chamber 129 to the forward chamber 119 between the opposed faces of the enlarged valve member portion 110 and sleeve end wall 104, a small passage 131 is extended through the valve member 109 from the socket 130 to the forward face of the enlarged valve member portion.

An encapsulated explosive charge 132 suflicient to actuate the valve 100 is placed into the powder chamber 129 and sealingly enclosed therein by an electrically initiated igniter needle 138 which may be generally arranged as those shown in the Schlumberger Patent No. 2,681,701. The igniter 133 is comprised of a small, explosive-filled metal tube 134 projecting from an enlarged head 135. An electrical filament (not shown) surrounded by the explosive in the tube 134 is electrically connected between the tube wall and an electrical lead 136 that is insulated from and sealed within the head 135 and ex tended rearwardly for a distance therefrom.

The exposed outer end 167 of the lead 136 is releasably connected to a fixed electrical contact 138 mounted on the exterior of the tool body 18 adjacent to the valve 100 and connected to one of the conductors in the suspension cable. By forming the igniter lead 136 from a fairly stiff and resilient material, its free portion may be bent in such a manner that, after the igniter 133 is positioned, its natural resilience will hold the exposed tip 137 in electrical contact with the fixed contact 138. A thin, electrically conductive ring 139 of an appropriate diameter is snugly fitted over the igniter tube 134 and engaged against the forward face of the head 165. By making the ring 139 slightly larger than the socket '130, when the igniter 133 is installed, the ring will be slightly deformed against the walls of the socket to provide a return electrical path from the metal tube 134 to the valve member 109 and tool body 18.

Although other means may be employed for fluidly sealing the igniter 133 within the valve member 109, it is preferred to form the enlarged head portion 135 of the igniter of an el-astomeric material and of a diameter that is slightly larger than the diameter of the socket 130. Thus, to prepare the valve 100 for operation, the explosive capsule 132 is first placed into the powder chamber 129. As the igniter 133 is inserted into the socket 130, the metal tube 134 will puncture the capsule 132. Then, as the igniter 133 is pressed into its final position, the slightly oversized head portion 135 will expand and form a tight seal with the walls of the socket 130.

It will be appreciated that after the valve 100 is assembled and installed in the tool body 18, all of the enclosed spaces, such as 119 and 120, therein will be at substantially atmospheric pressure. Thus, as the sample-taking apparatus 10 is lowered into a borehole, the hydrostatic pressure of the well control fluids will be imposed on the exposed end of the igniter head 135. Accordingly, to prevent the relatively pliable elastomeric material of the igniter head 135 from being extruded inwardly by the hydrostatic pressure into the outer ends of the gas passage 131 and powder chamber 129, an annular metal disc 140 is placed over the tube 134 in front of the igniter head as a support for the elastomeric material.

As the sample-taking apparatus 10 is being lowered into a well, the hydrostatic pressure of the well control fluids will act on the exposed outer end of the valve member 109 and enlarged igniter head 135 to hold the valve 100 closed. Moreover, it will be noted from FIG. 3 that the cross-sectional area of the valve member 109 at its rearward end (through O-ring 115) is somewhat greater than the cross-sectional area of the valve head 124 (through O-ring 125). Thus, even should the arrangement of the sample'taking apparatus 10 be such that the hydrostatic pressure of the well control fluids or some other pressure on the valve head 124 might tend to open the valve 100, the valve will still be positively held closed in view of the greater cross-sectional area at the opposite outer end of the valve member 109.

Turning now to the operation of the valve 100. When it is desired to open the valve 100, the power source 16 (FIG. 1) at the surface of the earth is connected by way of switch to the appropriate conductor in the cable 11. Passage of electrical current from the cable conductor 141 and filament (not shown) will ignite the igniter 133 which, in turn, detonates the powder in the punctured explosive capsule 132. Upon detonation of the powder capsule 132, the resultant gases that are generated thereby can escape only out of the socket 130 at the rearward end of the valve member 109. The pressure of these gases will, of course, tend to expel the igniter 133 rearwardly out of its socket 130. As the igniter head 135 first moves out of its socket 130,. however, the rearward end of the gass passage 131 is uncovered to divert gas pressure into the forward chamber 119 between the opposed faces of the enlarged valve member portion 110 and sleeve end wall 104. Thus, inasmuch as the rearward chamber 120 between the enlarged valve member portion 110 and annular stop 113 is at essentially atmospheric pressure, the explosive gas pressure in the forward chamber 119 will drive the valve member 109 rearwardly to unseat the valve head 124 from its seat 123. As the gas pressure continues to build up in the powder chamber 129, the igniter 133 will finally be expelled from its socket 130 to admit well control fluids therein. The well control fluids will, of course, enter the forward chamber 119 and move the valve member 109 to its fully-open position (if it has not already reached it) as well as to maintain the valve member in this position thereafter.

As an added feature, it has been found that by placing a thin, annular elastomeric disc 142 around the igniter tube 134 in front of the enlarged head portion 135, a better seal will be provided to confine the explosive gas pressures. Thus, when the explosive capsule 132 is detonated, the resultant gases will be confined somewhat longer to make the gas pressure more effective for opening the valve as well as insuring the expulsion of the igniter 133. Moreover, by more tightly confining these gases,

should a malfunction result in a lower than expected gaspressure, the gas pressure will still be more effectively utilized. It will be understood, however, that the igniter 133 will still be expelled from the socket 130 in any event.

To reduce the impact when the valve 100 is opened, resilient members, such as an O-ring 143, are disposed around the rearward valve member portion 112 inside of the rearward chamber 120. Thus, when the valve member 109 is blown rearwardly, the O-ring 143 serves as a cushion to protect the opposed faces of the enlarged valve member portion 110 and annular plug 113 from impact.

Turning now to FIG. 5, an alternate embodiment is shown of a valve 200 that is substantially arranged in the same manner as that shown in FIGS. 3 and 4. Inasmuch as this valve member 200 differs from the previously described valve member 100 in only minor details, it is believed necessary only to describe the more significant details thereof.

To facilitate manufacture and assembly, the valve 200 is made separately and arranged for insertion into a uniform lateral bore 201 that is open on one side of the tool body 18 and extends substantially therethrough. The body of the valve 200 is comprised of an enlarged head portion 202 from which a tubular member 203 projects. Longitudinally spaced lateral passages are provided through the tubular member 203 to serve respectively as inlet and outlet ports 204 and 205. A valve member 206 is cooperatively mounted on the free end of the tubular member 203, with a reduced-diameter forward portion 227 of the valve member being slidably received Within the tubular member 203.

As seen in FIG. 5, the forward face of an enlarged diameter portion 208 of the valve member 206 is normally engaged against the surface of the free end of the tubular member 203. The free end of the tubular member 203 may be slightly counterbored to provide an annular relief passage 209 to ensure that the gas pas-sage 210 through the valve member 206 is in communication with the entire surface of the free end. O-

rings

211 and 212 are mounted within the internal bore 213 of the tubular member 203 on opposite sides of the inlet ports 204 to fluidly seal those ports whenever the valve member 206 is in its port-closing position shown in FIG. 5,

To install the valve 200, the valve member 206 is inserted into the tubular member 203 and the assembled members are inserted into the bore 201 in the tool body 18 as shown in FIG. 5. O-rings 214-216 are spaced along the exterior of the tubular member 203 to fluidly seal the valve body within the tool body 18 and. isolate the inlet and outlet ports 204 and 205 from one another and the exterior of the tool. When the valve 200 is in position within the tool body 18, the inlet and outlet ports 204 and 205 will be in register with

circumferential grooves

217 and 218 in the wall of the bore 201 at the intersection therewith of

fluid passages

219 and 220 in the body.

The enlarged-diameter portion 208 of the valve member 206 is fluidly sealed by an O-ring 221 in that portion of the bore 201 of the tool body 18 ahead of the free end of the tubular member 203. The rearward reduced-diameter portion 222 of the valve member 206 extends through a reduced-diameter bore 223 at the rear of bore 201 and is fluidly sealed therein by an O-ring 224 around the bore wall. Thus, it will be appreciated that fluid-

tight chambers

209 and 225 are formed on opposite sides of the enlarged-diameter Valve member portion 208 similar to those previously described in conjunction with FIGS. 3 and 4.

The igniter 226 is identical to that already described with reference to FIG. 3, and it is therefore believed unnecessary to repeat that description. Thus, it will be appreciated that in general, the valve 200 in FIG. differs essentially from valve 100 in FIG. 3 by being so arranged that pressure entering the inlet port 204 will not tend to open the valve member 206 so long as it remains closed. The significance of arranging the valve member 206 in this manner to be pressure'balanced may best be appreciated by way of illustration.

Returning to FIGS. 2 and 3 for a moment, it will be seen that if valve 100 is employed as the flow-line valve 60 described in FIG. 2, any pressure surge in the main fluid conduit 61 will tend to unseat the valve head 124. Thus, should it be desired to actuate the sample-admitting means 23 (FIG. 2) first and take a shut-in pressure measurement of the formation, the shaped charge 62 would be detonated before the flow-line valve 60 is opened. Thus, a pressure surge of some magnitude would be transmitted through conduit 61 to the valves inlet port.

Ordinarily, such a pressure surge would not open the valve 60 prematurely since the hydrostatic pressure will usually be of suflicient magnitude to keep the valve fully closed. Where, however, the sample-taking apparatus is at a fairly shallow depth, the hydrostatic pressure force holding the valve 60 closed may be so low that a substantial pressure surge can overcome that force sufficiently to displace the valve member 109 (FIG. 3) at least partially to the rear. Should this happen, it will be realized that the electrical lead 136 will be disconnected from its contact 138. Moreover, once the shaped charge 62 (FIG. 2) is detonated, hydrostatic pressure will act on each end of the valve member 109; and the difference between the cross-sectional areas of its ends may well be insufficient for the hydrostatic pressure to return the valve member against the friction of O-rings 115-117. Thus, with electrical contact broken, the valve member 109 cannot be fully opened to the obvious detriment of the sampletaking operation.

The valve depicted in FIG. 5 is not, however, subject to premature opening from such causes. By sealing the forward portion 227 of the valve member 206 on each side of the inlet ports 204, it will be appreciated that the uniform diameter of the forward portion will not present an effective surface on which a pressure differential can act to shift the valve member longitudinally. Nevertheless, once the igniter 226 is detonated, it will be recognized that the valve 200 will operate in the same manner as the previously described valve 100.

Accordingly, it will be appreciated that the present invention has provided new and improved embodiments of explosively actuated valves that are particularly suited for service in high-pressure environments whereby the pressure of the environment itself is employed to not only assist in opening the valves but also to maintain the valves in their fully-opened position once they have been opened. Moreover, by expelling the igniters upon detonation, the valves will be positively opened and held open even though the explosive may not be fully effective. Furthermore, deformation of the valve members will be reduced to a minimum thereby permitting extended reuse of the valves and of the other components thereof.

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, and it is the aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. In apparatus for operating in response to an exterior environmental pressure: a body having first and second fluid passages and a bore therein intersecting said passages and a valve seat; a valve member having forward and rearward portions and an intermediate piston portion, said valve member being received in said bore and slidable therein between a first position and a second position wherein said forward valve member portion cooperates with said valve seat to prevent flow between said passages; first, second and third sealing means respectively sealing said valve member portions relative to said body to provide first and second isolated chambers in said bore on opposite ends of said piston portion, one of said chambers having a pressure different than the environmental pressure; normally-closed passage means for providing communication between the other of said chambers and the exterior environment; and selectively-operable explosive means for opening said passage means.

2. In apparatus for operating in response to an exterior environmental pressure: a body having a first and second fluid passages and a bore therein having a rearward portion open to the exterior and a forward portion intersecting said fluid passages; a valve seat between the junctions of said passages and forward bore portion; a valve member having forward and rearward portions and an intermediate piston portion, said valve member being received in said bore and slidable therein between a first position and a second position wherein said forward portion cooperates with said valve seat to prevent flow between said passage; first, second and third sealing means respectively sealing said valve member portions relative to said body to provide isolated chambers in said rear- \.ard bore portion on opposite ends of said piston por tion, one of said chambers having a pressure different than the environmental pressure; passage means in said valve member for providing communication between the other of said chambers and said open bore portion; means releasably sealing said passage means; and selectivelyoperable explosive means in said passage means for releasing said releasable sealing means.

3. In apparatus for operating in response to an exterior environmental pressure: a body having first and second fluid passages and a bore therein having a rearward portion open to the exterior and a forward portion intersecting said fluid passages; a valve seat between the junctions of said passages and forward bore portion; a valve member having forward and rearward portions and an intermediate piston portion, said valve member being received in said bore and slidable therein between a first position and a second position wherein said forward portion cooperates with said valve seat to .prevent flow between said passages, said valve member having an axial passage having an opening in the rearward end of said member; first, second and third sealing means respectively sealing said valve member portions relative to said body to provide isolated chambers in said rearward bore portion on opposite ends of said piston portion, one of said chambers having a pressure different than the environmental pressure; passage means in said valve member for providing communication between the other of said chambers and said axial opening; means releasably sealing said axial opening; and selectively-operable explosive means in said axial passage for expelling said releasable sealing means.

4. In a well tool for use in a well bore having fluid therein: a body having first and second fluid passages and a bore therein having a rearward portion open to the exterior of the body and a forward portion intersecting said fluid passages; a valve seat between the junctions of said passages and said forward bore portion; a valve member having forward and rearward portions and an intermediate piston portion, said valve member being received in said bore and slidable therein from a forward position wherein said forward portion cooperates with said valve seat to prevent flow between said passages to a rearward position, said valve member having an enlarged axial opening in its rearward end and a blind axial passage extending therefrom into said valve member; first, second 13 and third sealing means respectively sealing said valve member portions relative to said body to provide isolated chambers at atmospheric pressure in said rearward bore portion on opposite ends of said piston portion; a passage in said valve member providing communication between said forward chamber and said axial opening; and selectively-operable means for releasably sealing said axial opening including an explosive disposed in said blind axial passage, an electrically-responsive igniter extend- References Cited UNITED STATES PATENTS Desbrandes et a1. 166-63 X ing into said blind passage, and means fluidly sealing said 10 CHARLES OCONNELL Prim), Examiner DAVID H. BROWN, Examiner.

igniter within said axial opening.