US2742968A - Self-inflating balloon type formation tester - Google Patents

Description

April 24, 1956 A, B. HILDEBRANDT 2,742,968

SELF-INFLATING B11110011 TYPE FORMATION TESTER F11ed Dec. 11, 1952 1 alexander' n-fildebfmdt, Saver-150i' 2,742,968 `retreatedApr. 24, 1956` United States Patent Office SELF-INFLATING BALLOON TYPE FORMATION TESTER Alexander B. Hildebrandt, Tulsa, Okla., assignor to Esso Research and Engineering Company, a corporation of Delaware This invention is concerned with an improved apparatus for securing samples of formation fluids from a well bore to determine whether oil bearing strata have `been encountered. More particularly the invention relates to an improved formation tester of the inflatable balloon packer type that may be attached to the lower end of a drill pipe, wherein novel means are provided for inilating and detlating the balloon packer.

In conventional oil well drilling operations fluids known as drilling muds are employed to aid in carrying away cuttings and also to maintain a hydrostatic-head in the well to prevent the uncontrolled escape of gases or liquids from various formations encountered during drilling. One disadvantage of drilling with a drilling mud is that the sampling of natural fluids occurring in various formations is thereby rendered diillcult. To overcome this disadvantage various types of formation testers have been devised which are provided with means for reducing the hydrostatic pressure in the vicinity `of the formation to be tested in order that a sample of the natural fluids can be taken.

Many of these formation testers are provided with i.

inflatable elastic sleeves or packers for sealing off the portion of the well in which it is desired to reduce the hydrostatic pressure. The use of such elastic packers is particularly desirable since they can be expanded to give a thorough seal and yet may be readily removed from the` well after being deflated. Furthermore it is possible to position the elastic packers at any desired point in the well with very little diiliculty.

In formation testing using an inflatable elastic packer run on drill pipe or tubing some means must be provided for inllating the packer. The conventional means for doing this involves pumping drilling mud or other iluid such as plain water downthe pipe, so that with a` suitable arrangement of valves the necessary inflation pressure can be applied to the inside of the packer. Suitable means are provided to hold the pressure in the packer until the test has been completed. After the packer has been set against the formation the usual procedure is to reduce the pressure inside the drill pipe until` formation iluids can flow through it to the surface. j This can be done merely by substituting plain water for drilling mud in thelpipe but in many cases` it is necessary to swab down the iluid level in the pipe to the desired extent. An alternative procedure is to place a previously evacu-V ated sample chamber in the drill pipe and produce fluids into this sample chamber. With such a procedure the amount of iluid that can be sampled is limited by the capacity of the sample chamber. Obviously a procedure wherein the drill pipe can be run in empty is preferable since it provides for considerableytest capacity without the necessity of swabbing outthe pipe.` i i lt is an object of the present invention to provide means for formation testing in which an inflatable packer is used but in which neither an evacuated sample -chamber nor a swabbing operation is necessary. Itis a further object to provide a formation testing device that may be run into` the bore hole on an empty drill pipe and the packer inflated without requiring thatA fluids be pumped down the drill pipe, thus keeping the pipe empty for the collection of a sample of formation fluids.

Briefly the invention consists of an apparatus provided with means whereby the hydrostatic mud pressurev in the bore hole at the level of the formation under test is utilized to inflate the packer and to automatically collect a sample of the formation tluids as soon as the packer has set against the selected formation.

The nature of the invention and the objects thereby accomplished will be more fully understood from the ensuing description and from the accompanying drawing in which:

Figure 1 is a vertical sectional view of the upper portion vof a representative embodiment of the invention in position in a bore hole and j Figure 2 is a lower continuation of Figure l.

Referring specifically to the drawing it will be seen that the formation tester depicted is provided with a support member 12 that is attachable to a tool joint 11 which in turn can be attached to the lower end of a sectionof drill pipe (not shown). `The apparatus is shown in position` in a bore hole 10. The support 12 terminates in a lower rounded nose portion 13 to facilitate lowering through the b'ore hole. Positioned within the support member 12 is a cylindrical tube 16 which delines with the bore of the support member an annular passageway 17,`whose function will be explained later. There is no communication between passageway 17 and the bore 4 2 of tube 16 Adjacent` its upper end, lsupport member 12 is of enlarged external diameter to provide a shoulder 14 and some distance belowthis shoulder the support member has an `annular projection 1S in which an external groove is provided to receive aring seal 18. Fitting slidablyover the exterior of support member 12 is a sleeve member 19 having adjacent each end an internal groove, each one of which receives a ring seal 21 or 22. The middle portion of the bore of sleeve 19 is of enlarged diameter so that it fits slidably against projection 15 and defines with the adjacent portions of support member 12 an annular chamber 24 above kthe projection 15 and an annular chamber `26 below projection 15. A spring 27 is positioned within annular space 26 and presses at its upper end against the lower shoulder of projection `15 and at its lower end against the lower shoulder provided by the enlargement of the bore of sleeve 19. A port. 25 in the wall of sleeve 19 provides exterior iluid access to chamber 24. `A plug 53 set into suitably aligned openings in support member 12 and tube 16 has a central bore that provides a channel 54 connecting chamber 26 with bore 42 of tube 16. V

At the upper end of sleeve 19 an exterior shoulder 28 is provided which supports the lower end of an annular mechanical packer 29 that surrounds support member 12. The upper end of packer 29 lits against downwardly facing shoulder 14 on support member 1l2. The packer 29 is attached at its upper end to the support member 12 and at its lower end to the sleeve 19 and is held in place at each end by suitable means, as for example, by the tightly wound wires 3i). Thus as sleeve 19 moves upwardly with respect to support member 12 packer 29 will be made to expand against the walls of the bore hole as represented by the dotted lines 29a; Preferably the expansion of the packer is aided by a body of fluid 31 retained with the annular space defined by the packer and the support member 12.

Fastened `to the exterior of the lower portion of support member 12 is an inflatable elastic packer 33 held in place at each end by suitable means such as tightly wound wire 34. Fluid commmunication between the annular .passageway -'17 `andthe ination chamber 35 defined by packer. 33V and the support member- -12 is testablished through port 36.

An external recess 33 is provided in the wall of the inat'ablepackerfandicommunicating Y'with this vrecess is `-a production tube 39 iin-wh`ich-are `positioned yinterconnected `packing -elenientsti -in Ctheunranner disclosed in U. S. Paten't2j60l),f173 lof'fBenAW.' Sewell and'George Ramsey. "These A.packing elements establish a no'nc'ollap`sible passageway for t'the entrance of 'productionl iluids as -fully'discussed -in 4the `aforementionedpatent. Cornmu'nication` between the Aproduction ltube' 39'fand Athe in'ner bore 21210i tube v16'-is V'established 'through "channel 41 in an enlarged portionf'of which'is positioneda check v'alve'i, which4 isset to-open'at'a'low'pressure differential, say 2ior3 pounds. YA channel-4`5 irl-thehead'p'ortion r13 of fthe support' member lconnects annulus: 174 with an ex ternal port 50 through a check valve 46. Th'eifuuction of ethis-channel 'and'c'heck valve will'be explained later.

When the'apparatu's is preparedfor lowering into a bore hole the packers 29 and `33`are 'both"in'th'e'v nonexpanded'position and a"frang'ib'le or rupturable 'seal 56 'is positioned -in'thetop of'tube 16to Vsealdfl' inner borev 42 fromthe enlargedy bore 5S which is 'in open communication with the open 'drill pipe above. When Ithe desired 'level has b'eenreached in the bore 'hole a godevil-58y or similardeviceis dropped down through the drill-pipe to break the seal 56. lTo prevent 'the go-devil from Vsealing off tl-iejpassagewayit maybe desirable to provide the go-devilwithribs 59. l

When the seal 56 `isy broken the inner 'bore`42 will be exposed to atmospheric pressure, i. e. the pressure with inthe open'dr'ill pipe. 4Since the pressure of the drilling mud present A-i'n vthe borehole at the depth of the apparatus 'is higher 4than atmospheric, sleeve 19 will slide upwardly"with respect 't'of support member 12.

When the pressure within" bore 42 'is essentially the same as the pressure in the bore hole annulus, which will be' the casebefore seal'56 is broken, the force against the inner 'shoulder of Asleeve 19 that delines the top of chamber`24 will be count'e'rb'alanced by the force against the inner shoulder of sleeve 19 'that defines the bottom of chamber 26. 'When the pressure within 'chamber 26 is reduced, however, as a 'result of breaking seal 56, the upward Vforce 'on the sleeve will be. greater than the downward force. VHence sleeve 19 will move upward against the slight bias exerted by spring 27 and Ipacker 429 will be expanded outwardly to :the ,position .indicated by the dotted' lines 29a. vrThus ,the packer 29 willl be .expanded to seal oft' vthe bore hole annulus below this ypacker from the bore hole annulus above the packer.

"Spring 27 is not essential to the above described operation of sleeve 19 but it is xpreferred that it be used so that when the pressure Vin the borehole annulus is only slightly higher than .thepressure in bore 42, ywhich could occur as the apparatus' isv being lowered yinto the bore hole, the packer will not set prematurely. Thus aspring is selected such lthat sleeve .19 will not zmove up until thev pressurek dilerence `exceeds say' -50 pounds. The vpurpose lof ring seals 18,21 and22 is tcgprevent uid leakage past the 'sliding parts that they contact. y l

v4Because of the reduction in pressure within -the bore 42 upon ruptureof the seal 5 6, drilling mud-will also begin .to enter production tube 39 past valve-43 and -into the inner bore 42. vAs the volume of `rnudfin the`bore holeannulus in the vicinityof-the packer`33 is thus reduced drillingmud will enter through wport -51 .into annulus 17 V.and flow out through vport 36fintoithe inflation.,chamber 35 within packer33. This mud 4ilow will continue .as additional 'fluid enters productiontube 39 until the packer-33 presses up A againstthewalls of the bore hole. `Fluid within formation 60 will lthenilow throughI thejproduction tube39 into they innerbore 42.

The purpose of vcheck valve 46 is "to controlth'e inating pressure within the packer 33. Thus for example --ifthc'uidvpressure in thebore'hole annulus above-packer 29 should exceed the fluid pressure in the bore hole annulus at the bottom of the tester by more than say 50 lbs. fluid will ow down annulus 17 through the check valve 46 until the pressure differential drops below 50 lbs. It should be noted that packer 33 does not have to support more Vthana smalliditferential pressure and-hence its principal function is to isolate the portion of formation 60 being tested. l

When it is desired to terminate the test, drillingmud or other Iluidrn'ay be pumped down the drill pipe until the pressure within the inner bore 42 is about equal to the pressure in the bore hole annulus in the Vicinity of sleeve 19. When the pressure within annular space 26 approaches the pressure in the bore hole annulus sleeve 19 will move downward and retract packer 29. As a result, the bore hole pressures above and below packer 2'95w`ill bec'omeequalized 4and packer 33 will become d'atedfsnce jthe'gpressures inside and outside the packer 33"will also'jbecome equalized and the elasticity of lthe p'acker"materialY wlllfdraw 'the packer inwardly, 'the "in- Hating llluidminannular space 35 escaping through port 316,1;annulus`17fand port S1. The fluid sample that has been 'collected within vthe bore 32 will be prevented from escaping by the'check valve 43.

In La 'modification of 'the invention packer 29 may be omitted, and instead a conventional mechanical packer substituted; Such a packer would be mounted on support members movable relative to each other, the Upper one 'attaching' to lthe drill pipe andthe lower one to support 12. A conduit within the support members would connect annulus 17 with an exterior port above the rnechanical kpacker in the same manner as port 51. A conventional ta'ilpipe rwould be attached tothe bottom of support 12 'and 'would rea'ch to the bottom of the borehole Vso thatthe mechanical packer could be set by placing weight 'on the'dr'ill pipe, as in conventional practice. The inationlof packer 3.3 would then proceed upon rupture of se'al'5'6 'and the test proceed in the same manner as above described. To terminate the test it would merely be necessary to raise the drill pipe suiciently to unseat `the mechanical packer after which Vthe inflatable packer-l33 would deate in the same manner as already explained.

SIt is to beu'nderstodthat the invention is to be limited only by "the'fo'llowingfclaims, and not by the exact descriptioncontained in the foregoing specification, which has 'been presented merely by way of example and not of limitation.

"What is claimed is:

1. A'formation tester assembly for sampling uids from 'strata encountered in a well bore which comprises an 'elongatedrsupport member attachable to the lower @11d of a drill pipe and having a central bore communicating with'the interior of the drill pipe, an inatable elastic pabke'r attached to said support member, said packer having at le'a'st one test port in a side wall thereof, a mechanically expansible packer supported by the support member above vthe said inflatable `elastic packer, means `for expanding said mechanically `expansible packer, -a .passageway within said assembly terminating atV its lower end within said inflatable packerand at its upper end .in ag-.portfopening exteriorly of saidy assembly abovensaid mechanical packer, said passageway lacking communication -with kthe central bore of the support memberfa conduitv connecting the test port of the inflatable e'lastic1packer with the central bore of the said support member below said inflatable packer, and a pressure relief valve in said pressure relief conduit.

3. A formation tester `assembly for sampling fluids from strata encountered in a well bore which comprises an elongated support member attachable to the lower end of a drill pipe and having a central bore communieating with the interior of the drill pipe, a rigid sleeve slidably arranged on the exterior of said support member, a iirst flexible packer member surrounding said support member adjacent said sleeve, means fastening one end of said packer member to said support member, means fastening the other `end of said packer member to said sleeve whereby on longitudinal motion of said sleeve relative to said support member said packer member will expand outwardly, an inatable elastic packer fastened to said support member below said first packer member, said intlatable elastic packer having at least one test port in a sidewall thereof, a passageway within said support member terminating at its lower end within said inflatable packer and at its upper end in a port opening exteriorly of said support member above said rst packer member, said passageway lacking communication with the central bore of thesupport member, a conduit connecting the last named port of the inflatable elastic packer with the central bore of the support member, a check valve in said last named conduit, and a frangible seal within an upper section of said central bore above said last named conduit.

4. A formation tester assembly for sampling lluids from strata encountered in a well bore which comprises an elongated support member attachable to the lower end of a drill pipe and having a central bore communicating with the interior of the drill pipe, a portion of said support member being of enlarged cross-sectiona1 thickness, a rigid sleeve slidably arranged on the ex- 05 terior of said support member and enclosing and slidably engaging said enlarged portion thereof, said sleeve being of enlarged bore in its mid-portion whereby` to also slidably contact said support member above and below said enlarged portion and to deiine with said enlarged portion an upper annular chamber and a lower annular ber below said rst packer member, said inflatable elastic packer having at least one test port in a side wall thereof, a passageway within said support member terminating at its lower end within said inflatable packer and at its upper end in a port opening exterior of said support member above said rst packer member, said passageway lacking communication with the central bore of the support member, a conduit connecting the test port of the inflatable elastic packer with the central bore of the support member, a check valve in said last named conduit, and a frangble seal Within an upper section of said central bore above said last named conduit.

5. Formation tester assembly as dei-ined by claim 4 including a spring within one of said chambers exerting a bias on said sleeve in a direction resisting expansion of said rst named packer member.

References Cited in the le of this patent UNITED STATES PATENTS 2,600,173 Sewell et al. June 10, 1952

Claims (1)

1. A FORMATION TESTER ASSEMBLY FOR SAMPLING FLUIDS FROM STRATA ENCOUNTERED IN A WELL BORE WHICH COMPRISES AN ELONGATED SUPPORT MEMBER ATTACHABLE TO THE LOWER END OF A DRILL PIPE AND HAVING A CENTRAL BORE COMMUNICATPACKER ATTACHED TO SAID SUPPORT MEMBER, SAID PACKER HAVING AT LEAST ONE TEST PORT IN A SIDE WALL THEREOF, A MECHANICALLY EXPANSIBLE PACKER SUPPORTED BY THE SUPPORT MEMBER ABOVE THE SAID INFLATABLE ELASTIC PACKER, MEANS FOR EXPANDING SAID MECHANICALLY EXPANSIBLE PACKER, A PASSAGEWAY WITHIN SAID ASSEMBLY TERMINATING AT ITS LOWER END WITHIN SAID INFLATABLE PACKER AND AT ITS UPPER END IN A PORT OPENING EXTERIORLY OF SAID ASSEMBLY ABOVE SAID MECHANICAL PACKER, SAID PASSAGEWAY LACKING COMMUNICATION WITH THE CENTRAL BORE OF THE SUPPORT MEMBER, A CONDUIT CONNECTING THE TEST PORT OF THE INFLATABLE ELASTIC PACKER WITH THE CENTRAL BORE OF THE SUPPORT MEMBER, A CHECK VALVE WITHIN SAID LAST NAMED CONDUIT AND A FRANGIBLE SEAL WITHIN AN UPPER SECTION OF SAID CENTRAL BORE ABOVE SAID LAST NAMED CONDUIT.

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