US3385364A

US3385364A - Formation fluid-sampling apparatus

Info

Publication number: US3385364A
Application number: US557108A
Authority: US
Inventors: Frank R Whitten
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1966-06-13
Filing date: 1966-06-13
Publication date: 1968-05-28
Anticipated expiration: 1985-05-28

Description

N E T W H W R F FORMATION FLUID-SAMPLING APPARATUS 4 Sheets-Sheet 1 Filed June 13, 1966 INVENTOR ay 28, 1968 F. R. WHITTEN 3,335,3fi4

FORMATION FLUID-SAMPLING APPARATUS Filed June 13, 1966 Sheets-Sheet 2 Fro/o? f7. W/Z/ z few [N l ENTOR May 28, 1968 F. R. WHITTEN FORMATION FLUID-SAMPLING APPARATUS Filed June 13, 1966 4 Sheets-Sheet 3 May 2%, 196% F. R. WHITTEN FORMATION FLUID-SAMPLING APPARATUS 4 Sheets-Sheet 4 Filed June 13, 1966 Fran/4 AYTOR A'l' Y United States Patent 3,385,364 FORMATIQN FLUID-SAMPLING APPARATUS Frank R. Whitten, Houston, Tex, assignor to Sclriumberger Technology Corporation, Houston, Tex., a corporation of Texas Filed June 13, 1966, Ser. No. 557,108 21 Claims. (Cl. 166-100) This invention relates to new and improved fluidsamplin apparatus; and, more particularly, to sampletaking apparatus for obtaining one or more fluid samples from earth formations traversed by a well bore.

Heretofore, where it was desired to obtain fluid samples from earth formations, fluid-sampling apparatus such as, for example, those disclosed in Patent Nos. 2,674,313, 2,965,176, or 3,011,554 have been employed. In general, the tools disclosed in those patents include an extendible backup member that is selectively operable to urge an elastomeric sealing member on the other side of the tool into sealing engagement with the wall of the borehole. Where the formations are sufiiciently permeable, whatever recoverable formation fluids there may be therein will be expelled by formation pressure through a central opening in the sealing member and into a collecting chamber on the tool. In some instances, however, it may be necessary to first perforate the formation by means of a shaped charge coincidentally aligned with the sealing member. In any event, after a desired amount of the formation fluids are obtained, a selectively operable valve in the apparatus is actuated to close the samplereceiving chamber and the backup member is then retracted. The tool is thereafter retrieved and the fluid sample is examined.

Although such sample-taking tools have been highly successful heretofore, the present emphasis on minimizing well completion and testing expenses makes these tools somewhat ineflicient. For example, with these prior tools, only a single test can be performed for each trip into a well. Therefore, with such tools, where there is more than one potentially producible formation interval in a well, a separate testing operation must be conducted for each formation interval that is to be tested. Similarly, where a previous test is perhaps inconclusive, a complete operation must be made should more representative information be desired.

Such repeated operations will quite obviously consume a considerable amount of time in, for example, just lowering the tool into position in the well and removing it. Moreover, either an extra tool must be kept on hand or considerable time expended in reconditioning the tool for any additional runs. As a practical matter, therefore, the usual practice is to make only a single or, at best, two or three tests at the most promising intervals in a well and then hope that nothing of significance has been overlooked.

Accordingly, it is an object of the present invention to provide new and improved formation sampling apparatus that can obtain either one or a plurality of fluid san1- ples in a single descent into a well bore and in less time than has heretofore been possible.

This and other objects of the present invention are provided by arranging a plurality of new and improved self-contained sampling units into a unitary apparatus whereby each of the units may be selectively employed to obtain a single fluid sample.

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

FIG. 1 depicts sample-taking apparatus of the present invention as it might appear within a well bore;

FIG. 2 is a simplified, schematic representation of a portion of the apparatus depicted in FIG. 1;

FIGS. 3-5 are views similar to FIG. 2, but sequentially illustrating the progressive positions of various members of the apparatus during a typical testing operation;

PEG. 6 is an enlarged cross-sectional view of a preferred type of valve used in the invention and showing that valve in a closed position; and

FIG. 7 is a view similar to FIG. 6 but showing that valve in an open position.

Turning now to FIG. 1, fluid-sampling apparatus 10 incorporating the principles of the present invention is shown suspended from a multi-conductor cable 11 in a borehole 12 containing a well control fluid. The apparatus 10 has been positioned adjacent a particular formation interval 13 for collecting a sample of producible fluids from that formation. The cable 11 is spooled in the usual manner from a winch 14 at the earths surface, with some of its conductors being connected to a switch 15 for selective connection to a power source 16 and others being connected to typical indicating-and-recording apparatus 17.

For reasons that will subsequently become apparent, the fluid-sampling apparatus 10 is comprised of a plurality of tandemly arranged, self-contained sections 18 that are each capable of independent operation. Each of the testing sections 18 have extendible sample-admitting means 19 along one side of the sampling apparatus 10. As illustrated in FIG. 1, the sample-admitting means 190 for the testing section has been extended and sealingly engaged against the exposed face of the formation 13 for obtaining a sample of formation fluids therein.

Inasmuch as the particular constructional details of the several components are not necessary for fully understanding the fundamental principles of the present invention, a single one of the testing sections 18 is shown only schematically in FIGS. 25 to illustrate its operation during the course of a typical sampling operation. As illustrated in FIGS. 25, each testing section 18 of the fluidsampling apparatus 19 is basically comprised of pressure-responsive extendible sample-admitting means 19 for obtaining a fluid sample, sample-collecting means 20 for recovering a sample of formation fluids, and hydraulic retracting means 21 for restoring the sample-admitting means to its initial position. Each of these pressure-re sponsive means 1921 are independently controlled by separate, selectively operable, valve means 22-25 which, upon command from the surface, are opened to admit well control fluids from. the borehole 12 to that pressureresponsive means to utilize the hydrostatic pressure as a source of motivating power.

The sample-admitting means 19 are comprised of sealing means, such as an elastomeric annular sealing member 26, mounted on the outer end of a tubular member 27 that is slidably disposed within a lateral bore 28 in the testing section 1-3 and fluidly sealed therein as by an O-ring 29. Piston means, such as a tubular piston member 30 slida'bly disposed in an enlarged annular bore 31 concentrically formed around the lateral bore 28, are provided for moving the sealing member 26 into and out of engagement with an earth formation. The forward end of the piston 39 is enlarged, as at 32, to provide a rigid support for a substantial portion of the rear face of the sealing member 26. To ensure an even distribution of the well control fluids against the rear face of the sealing member 26, grooves 33 are formed in the front face of the support 32.

Although the stroke of the piston 6%) .alone will most likely be suflicient for most applications, it is preferred to telescopically dispose the piston in a sleeve member 34 slidably received in the bore 31 as means for increasing the distance that the sealing member 26 can be extended. To maintain the piston 30 coaxially aligned within the sleeve 34, the rearward end portion of the piston is enlarged for complementary reception within the sleeve. The forward end portion 36 of the sleeve 34 is reduced in diameter to receive the intermediate portion of the piston 30. Similarly, the rearward end portion 37 of the sleeve 34 is enlarged for complementary reception in the annular bore 31 and the intermediate portion of the sleeve is complementarily received within an inwardly directed shoulder 38 around the outer wall surface of the annular bore.

An O-ring 40 mounted around the inner wall surface of the annular bore 31 fluidly seals the piston 30 to the section 18. Similarly, O-rings 4'1 and 42 respectively on the rearward end 35 of the piston 3t) and forward end 36 of the slidable sleeve 34 fluidly seal these members to one another and provide an enclosed annular space 43 therebetween. An O-ring 44 around the rearward end portion 37 of the sleeve 34 and an O-ring 45 around the fixed shoulder 38 fluidly seal the slidable sleeve relative to the testing section 18 and provide an enclosed annular space 46 therebetween. The O-

rings

40, 41 and 44 also provide an enclosed annular space 47 in that portion of the annular bore 31 to the rear of the piston member 30 and sleeve 34. A generally longitudinal passage 48 between the enclosed

spaces

43 and 46 ensures that they will remain at the same pressure.

In a manner subsequently to be explained, the enclosed

spaces

43 and 46 are maintained at a low or atmospheric pressure during the initial operation of the apparatus .10. Thus, by applying an increase pressure within the rearward enclosed space 47, the piston 30 will be urged outwardly to extend the sealing member 26 away from the testing section 1'8. By arranging the opposite end portions 36 and 37 of the slidable sleeve 34 with essentially equal cross-sectional areas, the sleeve will usually remain stationary relative to the testing section 1 8 so long as the pressure in the rearward enclosed space 47 does not exceed that exterior of the apparatus 10. Thus, until the rearward end portion 35 of the piston 30 engages the forward end portion 36 of the sleeve 34, the sleeve member will remain stationary relative to the testing section 18. Then, once the end portions 35 and 36 have abu-tted, continued pressure in the space 47 will shift both the piston 30 and sleeve 34 outwardly until the rearward sleeve end 37 abuts the fixed shoulder 38. The initial spacing between the opposed surfaces of the sleeve end 37 and fixed shoulder 38 will of course determine the additional distance which the sealing member 26 can be extended without increasing the lateral dimensions of the testing section 18.

In the fluid-sampling tool disclosed in the aforementioned Patent No. 3,011,554, an extendible back-up shoe is extended outwardly against one face of a formation to laterally shift the entire tool in the opposite direction and urge the sealing member against the opposite wall of the formation. Although this procedure is generally satisfactory, should the borehole wall be washed out immediately in front of the sealing member, the tool body will only straddle the washed-out portion and the sealing member cannot be brought into contact with the borehole wall.

Accordingly, as a significant distinction from tools of the prior art, the sample-admitting means 19 are themselves moved outwardly against a formation rather than being engaged thereon only by lateral displacement of the entire tool itself. Such positive extension of the sample-admitting means 19 ensures that the sealing member 26 will continue moving outwardly until it engages the borehole wall. While the Sealing member 26 is moving toward a formation, the body of the apparatus 10 will be shifted in the opposite direction and against the opposite borehole wall. Thus, regardless of the condition of the wall in a borehole, the sealing member 26 will always be engaged against the face of the formation so long as the combined strokes of the piston 30 and sleeve 34 are suflicient to bring the sealing member into contact with the formation.

To provide increased fluid communication with an earth formation, perforating means, such as a shaped charge 49 enclosed within a fluid-tight case, are mounted in the forward end of the tubular member 27. Electrically responsive detonating means, such as an igniter 50 disposed within the case at the rear of the shaped charge 49, are connected through an electrical conductor 51 extending through the tubular member 27 and terminated at the rear of the lateral bore 28 by a suitable fluid-tight connector 52. To accommodate the lateral extension of the sample-admitting means 19, the conductor 51 is made of a sufiicient length and preferably looped somewhat in the manner illustrated in the drawings.

The sample-collecting means 20 includes a samplereceiving chamber which is divided into upper and

lower compartments

53 and 54 separated from one another by a partition 55 having a flow restriction or orifice 56 therein. A liquid cushion 57, such as water, is disposed in the lower compartment 54 and isolated from the sampleadmitting means 19 by a floating piston 58 which is sealiugly engaged within the lower compartment. Since the upper compartment 53 is initially empty and at a low or atmospheric pressure, formation fluids (at whatever the formation pressure is) will enter the lower compartment 54 and move the piston 53 toward the partition 55 at a rate regulated by the discharge of the water cushion 57 through the orifice 56.

To conduct a formation fluid sample from the sampleadmitting means 19 to the sample-collecting means 20, a series of interconnecting passages 59-61 are formed in the testing section 18 between the rearward end of the lateral bore 28 and the lower or sample-receiving compartment 54. Selectively operable valve means, such as an independently operated normally-closed valve 62 and a normally-open valve 63, are serially arranged to control fluid communication through the passages 59-61, with the first valve 62 being opened to admit a fluid sample to the lower compartment 54 and the second valve 63 being subsequently closed to trap a fiuid sample in the samplereceiving compartment. Pressure-measuring means, such a pressure transducer 64, connected to the passage 60 between the

valves

62 and 63 provide a varying signal that is transmitted through the cable 11 to the indicatingand-recording apparatus 17 at the surface.

The normally-closed so-called flow-line valve 62 serves to prevent entry of fluids in well bore 12 through the central opening of the sealing member 26 and into the sample-receiving compartment 54 as the apparatus 10 is being positioned. The flow-line valve 62 is comprised of a valve member 65 of a uniform diameter having a pair of spaced O-rings 66 and 67 mounted thereon and slidably disposed in a cylindrical bore 68. By connecting the passage 59 to the bore 68 at a point between the positions normally occupied by the O-rings 66 and 67 when the valve 62 is closed, it will be appreciated that the uniform diameter of the valve member 65 will not present an effective differential area surface on which pressure can act to shift it open. The next passage 60 is connected to the bore 68 on the opposite side of where the O-ring 66 is normally positioned. Thus, when the valve member 65 is in the position depicted in FIG. 2, fluid communication between the

passages

59 and 60 will be blocked. 0n the other hand, by moving the valve member 65 further into the bore 63, communication will be established.

To actuate the flow-line valve 62, piston means, such as an enlarged head portion 69 on the end of the valve member 65 opposite of the O-rings 66 and 67, are provided. The enlarged head portion 69 is received in an enlarged piston cylinder 70 coaxially aligned with the bore 68 and the head portion is fluidly sealed therein by an O-ring 71.

The normally-open so-called seal valve 63 is provided to close-oil the sample-receiving compartment 54 once a fluid sample is collected. The seal valve 63 is comprised of a slidable cylindrical valve member 72 and an enlarged piston or head portion 73 respectively disposed in complementary connected

coaxial bores

74 and 75. An O-ring 76 around the enlarged head 73 fluidly seals that member in the enlarged bore 75. Spaced O-rings 77 and 78 are appropriately arranged around the valve member 72. The intermediate O-ring 73 is always fluidly sealed within the bore 74 and the portion of the valve member 72 carrying the forward O-ring 77 is slightly enlarged and arranged to be fluidly sealed within a complementary portion of the bore 74 whenever the valve member is moved from its normally-open position into its closed position. The intermediate passage 6t} is connected to the end of the bore 74 beyond the position occupied by the O-ring 77 Whenever the valve 63 is closed. The passage 61 leading to the sample-receiving compartment '54 is connected to the bore 74 at a position intermediate of the O-rings 77 and 78 whenever the valve 63 is in its closed position. Thus, whenever the seal 63 is open, the pressure of fluids in the passages 60 and 61 will tend to hold the seal valve open. On the other hand, once the seal valve 63 is closed, the pressure of fluids collected in the sample-receiving chamber 54 will be acting on the enlarged portion adjacent to the O-ring 77 to maintain the seal valve closed.

It will be recalled that in most tools of the prior art (e.g., the fluid-sampling tool disclosed in the aforementioned Patent No. 3,011,554), actuation of the various movable elements has been accomplished by a self-contained hydraulic system in the tool. Although such hydraulic systems have been quite successful, they nevertheless require considerable space in a tool in order to provide a sutficient volume of hydraulic fluid to accommodate the displacement of the various elements. More over, should only a single fluid seal in the hydraulic system fail, the formation-sampling tool may very likely be rendered inopeartive.

Accordingly, to conserve space as well as to provide for more reliable operation, the apparatus 1'!) of the present invention is so arranged that the hydrostatic pressure of the fluids in the well bore 12 will serve as the pressure media for actuation of the various elements thereof. To accomplish this, each of the pressure-responsive means 19-21 are provided with the individual control valves 22-25 that are selectively operable in response to a signal from the surface.

As will subsequently be described in greater detail, each of these valves 2225 are normally closed and are individually opened in response to a signal from the surface to admit the well control fluids to the piston actuator of the particular pressure-responsive means 19-21 that it is controlling. For example, to extend the sample-admitting means 19, the valve 24 is opened on command to admit the well control fluids through a passage 79 into the rearward space 47 behind the piston member 30 and slidable sleeve 34. Inasmuch as the

enclosed spaces

43 and 46 are initially at a low or atmospheric pressure, introduction of the hydrostatic pressure of the well control fluids into the rearward space 47 will move first the piston member 30 outwardly and, if clearance in the borehole 12 permits, then the slidable sleeve 34.

Similarly, the valve 23 is arranged to control communication through a passage 80 leading to the portion of the enlarged bore 70 between the O-rings 67 and 71 of the flow-line valve 62. In this manner, opening of the valve 23 will admit the well control fluids into this portion of the bore 70 to move the piston 69 and valve member 65 to the right as viewed in FIG. 2 to open the flow-line valve 62. The valve 22 similarly controls communication through a passage 81 leading to the enclosed portion of the enlarged bore 75 behind the piston portion 73 of the seal valve 63 and causes the enlarged piston 73 and valve member 72 to move to the left as viewed in FIG. 2 to close the seal valve.

As seen in FIG. 2, the hydraulic retracting means 21 are comprised of hydraulic pressure-developing means 82 whose outlet passage 83 is connected by way of a normally-closed valve 84 to emergency release means 85 and the piston means 30 of the sample-admitting means 19. In this manner, whenever the hydraulic valve 84 is opened, hydraulic pressure is applied to the piston means 36 to retract the sample-admitting means 19. Should some malfunction in the hydraulic retracting means prevent the retraction of the sample-admitting means 19, the emergency release means 85 are arranged to admit hydrostatic pressure to the enclosed space 43 for equalizing the pressure across the piston means 30.

The hydraulic pressure-developing means 82 are comrised of piston means, such as a piston 86 complementarily fitted and fluidly sealed within a stepped cylinder having an open enlarged-diameter portion 87 and an enclosed reduced-diameter portion 88. The hydrostatic pressure of the well control fluids acting on the exposed portion of the piston 86 will develop a greater pressure in a suitable hydraulic fluid confined in the reduceddiameter cylinder portion 88. It will be recognized, of course, that the magnitude of the developed hydraulic pressure will be dependent upon the ratio of the enlarged and reduced bore portions 87 and 88.

Although only a single piston will develop suflicient hydraulic pressure in the space 88, it is preferred to slidably dispose a second piston 39 in a stepped bore 90 through the piston 86. In this manner, a somewhat greater displacement volume will be provided for the hydraulic system to ensure reliable actuation of the various elements in the testing section 18. It will be understood, of course, that so long as the hydraulic valve 84 is closed, the hydraulic pressure developed in the reduced-diameter bore portion 38 will be confined therein. To ensure that the inner piston 89 will move inwardly ahead of the outer piston 86, the inner piston is arranged with a larger ratio of cross-sectional areas than the outer piston. In this manner, the inner piston 89 will always be moved inwardly before the outer piston 86.

The normally-closed hydraulic valve 84 is comprised of a slid-able cylindrical valve member 91 of a uniform diameter and an enlarged piston or head portion 92 respectively dispose-d in complementary and connected coaxial bores 93 and 94. An O-ring 95 around the enlarged head 92 fluidly seals that member in the enlarged bore 94. A pair of spaced O-rings 96 and 97 are appropriately arranged on the valve member 91 to closeoif fluid communication between the passage 83 and another passage 98 at the inner end of the bore 9 3 so long as the valve member is in its closed position as depicted in FIG. 2. To actuate the hydraulic valve 84, one or

more control valves

25a and 25b that are selectively operable in response to a signal from the surface are provided. By arranging these normally-

closed valves

25a and 25b to be opened upon command from the surface, well control fluids can be selectively admitted into the enlarged bore portion 94 to act on piston 92 when it is desired to open the hydraulic valve 84. By providing more than one control valve 25, should the first valve 25a fail to open, the second valve 25!) will give a second opportunity for the hydraulic valve 84 to be actuated when it is desired to retract the sampleadmitting means I19.

The emergency release means 85 is comprised of an extendible member 99 that is slidably disposed in a lateral stepped bore 100 in the testing section 18 that is parallel to the piston bore 31 but opens on the opposite side from the sealing member 26. Passages 9S and 101 interconnect the lateral bore to the sample-admitting means 19 and the hydraulic valve 84. Spaced O-

rings

102 and 103 fluidly seal the extendible member 99 in the lateral bore 100. An axial bore 104 is provided through the central portion of the extendible member 99 and terminate therein just short of its outer end 1105. The opposite end of the axial bore 104 is enlarged, as at 106, and opened to the

passages

98 and 101 by a lateral port 107 between the O-

rings

102 and 103. A spring-biased ball check valve 108 is disposed in the enlarged bore 106 for a purpose to be subsequently described.

The outer end 105 of the extendible member 99 is sufliciently weakened by means, such as a notch 109, for displacing the members outer end sufiiciently to admit well control fluids into the axial bore 104 whenever a lateral or sideward force is applied to the outer end. The outer end 1105 of the extendible member 99 is preferably enlarged and provided with a tang v110 to be pushed against or into the formation wall. The inner end 111 of the extendible member 99 is enlarged and arranged as a piston for moving the extendible member outwardly. By connecting the enclosed space 112 behind the piston portion 1 11 of the extendible member 99 to the enclosed space 47 by

passages

79 and 113, the extendible member will also be moved outwardly but in the opposite direction from the sample-admitting means 19 whenever the control valve 24 is opened.

Turning now to the operation of the present invention. To obtain a fluid sample from a particular formation, the formation-sampling apparatus 10 is positioned as shown in FIG. 1 in the borehole 12 opposite the formation 13. At this point, the various elements of the apparatus 10 will be in their positions substantially as shown in FIG. 2. Although all of the control valves 22-25 are still closed at this time, the hydrostatic pressure of the well control fluids will be effective to develop a greater hydraulic pressure in the reduced-diameter bore portion 88 of the pressure-developing means 82 as the apparatus 10 is being positioned.

As best seen in FIG. 3, once the apparatus 10 is in position, the control valve 24 is opened to admit well control fluids into the

passages

79 and 113 to simultaneously extend the piston 30 and extendible member 99 in opposite directions. Then, once either the outer end 105 of the extendible member 99 or the body of the apparatus 10 has engaged the opposite wall of the formation 13, continued movement of the piston member 30 will urge the sealing member 26 into sealing engagement against the opposite surface of the formation with a force that is equal to the hydrostatic pressure multiplied by the difference in cross-sectional areas of the piston 30 through O-rings 41 and 42.

Those skilled in the art will appreciate that it is not too uncommon for a well tool to become stuck by differential pressures in a borehole. Where this happens, at least a portion of one side of the tool will sufiicienty be imbedded through or into the layer of mudcake lining the borehole walls that the marginal surfaces of the tool will be sealed into the mudcake. Thus, whatever differential therein between the hydrostatic pressure of the well control fluids and the pressure of the formation or mudcake at that point will tend to hold the tool against the borehole wall. Accordingly, although the major function of the emergency release means 85 is to enable the sampleadmitting means 19 to be retracted should the hydraulic retracting means 21 fail, the extendible member 99 also may serve to support the apparatus 10 away from the borehole wall. As seen in FIG. 3, if the borehole wall is not cut away at this point, the enlarged end 105 will contact the wall as the sample-admitting means 19 is extended. Although the extendible member 99 moves outwardly only a short distance, it will hold the apparatus 10 at least partially out of the mudcake. Thus, the emergency release means 85 will also reduce the possibility of the apparatus 10 being differentially stuck.

As best seen in FIG. 3, it should also be noted that by appropriately arranging the O-ring 40 as shown, the piston 30 needs to move outwardly only a short distance before the O-ring is uncovered. Once the O-ring 40 is uncovered, well control fluids can also enter the space 47 from between the adjacent faces of the sealing member 26 and the support 32. In this manner, should the passage 79, for example, become plugged, positive actuation of the piston 30 is assured by bypassing the well control fluids around the O-ring 40.

The flow-line valve 62 must, of course, be opened before a fluid sample can be admitted into the samplecollecting compartment 54. Thus, in one mode of operation, the control valve 23 is opened before the control valve 24 so as to introduce a small amount of the well control fluids into the lower compartment 54 before the sample-admitting means 19 are extended. In this manner, the ditferential between the formation pressure and the low pressure in the sample-collecting compartment 54 will be lessened sufficiently to minimize the risk of unduly shocking the formation 13. Although some well control fluids will enter the sample-collecting compartment 54 ahead of any formation fluids, their effect will be negligible and easily compensated for when analyses are made of the fluid samples. In another mode of operation of the apparatus 10, the flow-line valve 62 is left closed until after the sealing member 26 has been sealingly engaged against the formation 13. This latter mode of operation will allow only the well control fluids upstream of the flow-line valve 62 to enter the sample-collecting means 20.

In any event, whenever the flow-line valve 62 is opened, whatever producible fluids thereare in the formation 13 will, if possible, flow through the central opening of the sealing member 26, into the tubular member 27, and on through the passages 59-61 into the sample-collecting compartment 54.

In some instances, however, it may be that formation fluids are incapable of flowing readily through the sealedotf portion of the formation. By monitoring the pressure in the flow passage 60 as indicated by the pressure transducer 64, a skilled operator can determine whether a fluid sample has entered the sample-collecting compartment 54. Accordingly, should these pressure measurements indicate that no fluid sample has been collected, the power source 16 (FIG. 1) will usually be connected to a predetermined one of the conductors in the cable 11 to detonate the shaped charge 50. Upon detonation of the shaped charge 50, the resultant perforating jet will produce a perforation 114 as best seen in PEG. 4. Should there be recoverable formation fluids that can flow into the perforation 114, they will enter thet sample-admitting means 19 and flow into the sample-collecting compartment 54- by way of passages 5961.

Irrespective of how the sample is obtained, whenever a suflicient time has elapsed or pressure measurements by the transducer 64 indicate that the sample-collecting compartment 54 is most likely full, the control valve 22 is opened. Opening of the control valve 22 will admit the well control fluids into the passage 81 and in turn close the seal valve 63. Once the seal valve 63 is closed, whatever fluids there may be in the sample-collecting compartment 54 will be trapped therein.

As best seen in FIG. 5, to retrieve the apparatus 10, the control valve 25a is first opened to, in turn, open the normally-closed hydraulic valve 84. By opening the valve 84, the high pressure hydraulic fluid is admitted through the

passages

83, 98, 101 and 48 into the

spaces

43 and 45 that were initially at atmospheric pressure. Since the hydraulic pressure is greater than the hydrostatic pressure of the well control fluids, as the hydraulic fluid enters these

passages

98 and 101 and

spaces

43 and 46, the piston 30 and extendible member 99 are usually returned to their initial positions. Once these

members

30 and 99 have been returned, the apparatus 10 can, of course, be retrieved from the well bore 12.

In some instances, however, it will be recognized that the differential between the hydrostatic and formation pressures may be sufiicient to hold the sealing member 26 firmly engaged against the formation 13. Accordingly, to prevent this, an equalizing valve 115 is arranged as seen in FIGS. 4 and 5 in such a manner that once the control valve 25 is opened, the pressured hydraulic fluid will also open the equalizing valve to admit well control fluids into the bore 28. The equalizing valve 115 is comprised of a cylindrical valve member 116 having an enlargeddiameter piston portion having an O-ring 117 and an O- ring 118 around its intermediate portion and slidably disposed in a pore 119 opening to the exterior of the testing section 18. An intermediate portion 120 of the bore 119 is reduced in diameter so as to sealingly receive the O- ring 118 and block communication from the exterior to a passage 121 leading to the lateral bore 28. When the valve member 116 is in its normally-closed position (as seen in FIG. 4), the hydrostatic pressure of the well control fluids will hold it closed so long as the hydraulic valve 84 is closed.

As best seen in FIG. 5, opening of the hydraulic valve 84 will move the valve member 116 outwardly to admit the well control fluids through the passage 121 into the lateral bore 28. Once well control fluids are admitted into this lateral bore 28, they will pass through the tube 27 to the front of the sealing member 26 to equalize pressures thereacross and facilitate disengagement of the sealing member from the formation wall.

Should there be some malfunction in the hydraulic retracting system 21, as, for example, sticking of the hydraulic valve 84, the apparatus can still nevertheless be retrieved. Should the necessity arise, the outer end 105 of the extendible member 99 can be quiet simply failed across the notch 109 by picking up on the apparatus 10. Then, once the outer end of the axial bore 104 is opened, the well control fluids will be admitted into the

spaces

43, 46 and 106. Thus, although there will be no retracting force as where hydraulic pressure is applied, the hydrostatic pressure acting across the

retractible members

30 and 99 will at least be equalized. Thus, once the pressure forces are removed, the apparatus 10 can be pulled upwardly and the sealing member 26 and extendible member 99 will gradually be worked back into their respective retracted positions.

It should be noted in passing that the check valve 108 will permit well control fluids to enter the hydraulic system once the outer end 105 is failed. Should, however, the outer end 105 be accidentally snapped-off, the hydraulic pressure will merely hold the ball 108 closed and no hydraulic fluid will be lost as the hydraulic retracting means 21 are actuated.

Turning now to FIGS. 6 and 7, one embodiment is shown of a control valve 200 such as may be used at 22- 25. The control valve 200 is comprised of a cylindrical valve member 201 that is slidably received in a bore having a closed inner portion 202 and an enlarged outer portion 203 that is open to the exterior of the testing section 18.

Lateral passages

204 and 205 in the testing section 18 respectively intersect the inner bore 202 and the outer bore 203. A pair of spaced O-rings 206 and 207 are suitably arranged on the valve member 201 to straddle the first passage 204 whenever the valve member is in its normal position. This first passage 204 is open to the exterior of the apparatus 10 whereas the other passage 205 is connected to whatever device the control valve 200 is to operate.

The outer end of the valve member 201 is hollowed to provide a chamber 208 that is closed at its inner end and open at its outer end. To actuate the control valve 200, and electrically initiated igniter needle 210 which may be generally arranged as those shown in the Schlumberger Patent No. 2,681,701 is sealingly disposed into the chamber 208. As disclosed in the Schlumberger patent, the igniter 210' is comprised of a small, explosive-filledmetal tube 211 projecting from an enlarged head 212..

An electrical filament (not shown) surrounded by the explosive in the tube 211 is electrically connected be- 10 tween the tube and wall and an electrical lead 213 that is insulated from and sealed within the head 212 and extended rearwardly for a distance therefrom. The lead 213 is, of course, connected to an appropriate one of the conductors in the suspension cable 11.

Although other means may be employed for fluidly sealing the igniter 210, it is preferred to form the enlarged head portion 212 of the igniter of an elastomeric material having a diameter that is only slightly larger than the diameter of an intermediate portion 209 between the reduced bore portion 202 and enlarged bore portion 203. To ready the valve 200 for operation, the igniter 210 is fitted into place. Then, as the igniter 210 is pressed into position, the slightly oversized head 212 will expand and form a tight seal with the walls of the intermediate bore portion 209.

By connecting the device to be controlled to the outer passage 205 and the inner passage 204 to the exterior of the apparatus 10, the valve member 201 will have no pressure forces tending to open or close it. The hydrostatic pressure acting on the enlarged igniter head 212 will be carried by the shoulder 214 at the junction of the

bores

202 and 203 and only urge the elastomeric material into tighter sealing engagement.

As seen in FIG. 7, to operate the valve 200, the igniter 210 is electrically initiated, and as the explosive in the igntier tube burns, the resulting gases will impel the valve member 201 further inwardly into the blind bore 202. The open end of the valve member 201 is preferably fitted somewhat snugly into a tube 214 that may be secured to the base of the igniter head 212. In this manner, the tube 214 will serve somewhat as a gun barrel by confining the valve member 201 therein for a sufiicient time to allow the gas pressure developed in the igniter tube 210 to forcibly drive the valve member into the bore 202.

It will be recognized, of course, that any reasonable number of testing sections 18 can be assembled into a unitary apparatus 10 to meet a given situation. By arranging a number of testing sections 18 as shown in FIG. 1, the apparatus 10 can be positioned in the borehole 12 and a number of samples obtained. It would be of no consequence, of course, whether the number of samples obtained were from the same formation, as at 13, or from a number of different formation intervals in the well. In either instance, by arranging the apparatus 10 in the desired fashion, a number of formation fluid samples can now be selectively obtained.

It should also be appreciated that more than one sample can be obtained at the same time. Thus, as seen in FIG. 1, assuming that the formation 13 is of sufficient thickness, a fluid sample could be taken either at the same time or at a short interval apart by the sample-admitting means 19c and 19d.

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.

What is claimed is:

1. A well tool adapted for reception in a well bore and comprising: a body having first and second bores therein and each open at one end thereof on the same surface of said body; means on said body for engaging the wall of a well bore including a movable tubular member in said first bore and having a forward portion adapted for projection from the open end thereof and a rearward portion for fluid communication to the interior of said body; means for extending said tubular member relative to said body including piston means in said second bore and defining a first enclosed space therein behind said piston means, means fluidly sealing said piston means relative to said body and defining a second enclosed space in said second bore ahead of said piston means, and means responsive to outward movement of said piston means for moving said tubular member outwardly; first selectivelyoperable means for introducing a first fluid into said first enclosed space under sufficient pressure to move said piston means outwardly; and second means selectively operable from the surface for introducing a second fluid into said enclosed space under a pressure suflieient to retract said tubular member.

2. The well tool of claim 1 further including means selectively operable from the surface for introducing the first fluid into said second space to equalize pressure differentials across said piston means.

3. The well tool of claim 1 further including means on the forward portion of said tubular member for establishing a fluid seal with the well bore wall; means fluidly sealing said tubular member in said first bore and defining an enclosed chamber therein; and compartment means on said body adapted for being in fluid communication with said chamber.

4. The well tool of claim 3 further including selectivelyoperable shaped charge means mounted in the forward portion of said tubular member and defining an annular flow passage therearound.

5. The well tool of claim 4 further including means selectively operable from the surface for introducing the first fluid into said second space to equalize pressure differentials across said piston means.

6. The well tool of claim 5 wherein the first fluid is fluid in the well bore, said second space is normally at a reduced pressure, and said body has a third bore therein and open at one end; and said second means are comprised of an extendible member movable disposed in said third bore, passage means between the outer end of said extendible member and said second space, means selectively operable from the surface for extending said extendible member and engaging said outer end thereof against the well bore wall, and means normally closing the outer end of said passage means and responsive to longitudinal movement of said body relative to the well bore wall whenever said extendible member is in an extended position for opening said outer end of said passage means to admit fluids from the well bore therethrough and into said second space.

7. The well tool of claim 6 wherein said means for extending said extendible member include second piston means in said third bore and defining a third enclosed space therein behind said second piston means, and second passage means between said first and third spaces whereby said extendible member will be extended upon outward movement of said first-mentioned piston means.

8. The well tool of claim 7 further including selectivelyoperable shaped charge means mounted in the forward portion of said tubular member and defining an annular flow passage therearound.

9. Formation-sampling apparatus adapted for reception in a well bore having fluids therein and comprising: a body having inner and outer coaxial lateral bores therein and each open at one end thereof on the same side of said body; sample-admitting means on said body including a slidable tubular member partially disposed in said inner borc, means fluidly sealing said tubular member relative to said body and defining an enclosed chamber in said inner bore, and sealing means on the exposed portion of said tubular member for establishing fluid communication with an earth formation; sample-collecting means adapted for being in fluid communication with said enclosed chamber; means for extending said sample-admitting means into fluid communication with an earth formation including a sleeve member in said outer bore and movable therein between a retracted and an extended position, an annular piston member telescopically disposed in said sleeve member and movable therein between a retracted and an extended position, means fluidly sealing said piston and sleeve members to one another at spaced intervals and providing a first enclosed space at a reduced pressure therebetween, means fluidly sealing said sleeve member to said body at spaced intervals and providing a second enclosed space at a reduced pressure around said sleeve member and within said outer bore, means fluidly sealing said piston member to said body and providing a third enclosed space at the rear of said outer bore, and means responsive to outward movement of said piston member for extending said sample-admitting means; and selectively-operable means for introducing well fluids into said third space.

10. The apparatus of claim 9 wherein said means fluidly sealing said piston member to said body are on said body and so located that, upon forward movement of said piston member, said piston member will be disengaged therefrom to admit well fluids through said outer bore into said third space.

11. The apparatus of claim 9 further including passage means through said sleeve member betwecn said first and second spaces; and means selectively operable from the surface for admitting well fluids into said first and second spaces to equalize pressure differentials across said I piston member.

12. The apparatus of claim 9 further including selectively-operable shaped charge means mounted in the forward portion of said tubular member and defining an annular flow passage therearound.

13. The apparatus of claim 9 further including passage means through said sleeve member between said first and second spaces; and first means selectively operable from the surface for introducing a fluid into said first and second spaces under a pressure suflicient to retract said members.

14. The apparatus of claim 13 further including second means selectively operable from the surface for admitting well fluids into said second and third spaces to equalize pressure differentials across said piston member.

15. The apparatus of claim 14 wherein said body has a third lateral bore therein and open at one end; and said second means are comprised of an extendible member movably disposed in said third bore, second passage means between the outer end of said extendible member and said second space, means selectively operable from the surface for extending said extendible member and engaging its outer end against an earth formation, and means normally closing the outer end of said second passage means and responsive to longitudinal movement of said body relative to the earth formation whenever said extendible member is extended for opening the outer end of said second passage means to admit fluids from the well bore therethrough and into said second space.

16. The apparatus of claim 15 wherein said means for extending said extendible member include second piston means in said third bore and defining a fourth enclosed space therein behind said second piston means, and third passage means between said fourth and third spaces whereby said entendible member will be extended upon outward movement of said first-mentioned piston means.

17. A well tool adapted for reception in a well bore having fluids therein and comprising: a body; means for establishing a fluid seal against a wall in a well bore; inner and outer tubular members telescopically arranged together and adapted for movement between an extended and a retracted position, one of said telescoping members being coupled to said sealing means and at least one other of said telescoping members being received in said body, means fluidly sealing said body and telescoping members to one another and defining first and second sealed chambers at a reduced pressure therebetween and an enclosed chamber therebehind; and means selectively operable for admitting well fluids into said enclosed chamber for extending said telescoping members.

13. The well tool of claim 17 further including first means selectively operable for introducing a hydraulic fluid into said sealed chambers at a pressure suificient to retract said telescoping members.

19. The well tool of claim 18 further including second means selectively operable for admitting well fluids into said sealed chambers to equalize pressure differentials across said telescoping members.

20. The well tool of claim 18 wherein said first means includes pressure-multiplying means responsive to the pressure of the well fluids for developing a greater hydraulic pressure.

21. The well tool of claim 20 wherein said pressuremultiplying means includes first and second piston members each having portions with enlarged and reduced diameters cooperatively telescoped together and received in said body, and valve means selectively operable from the surface and between said pressure-multiplying means and said sealed chambers.

References Cited UNITED STATES PATENTS Pollard 166-100X Nelson 166-l00 X Chambers 166100X Zandmer 166-100 Whitten 166100 X Brieger et a1 166100 X Urbanosky 166l00 CHARLES E. OCONNELL, Primary Examiner.

DAVID H. BROWN, Examiner.