US3173485A

US3173485A - Well formation isolation apparatus

Info

Publication number: US3173485A
Application number: US757266A
Authority: US
Inventors: Jr Samuel C Bretzke
Original assignee: Halliburton Co
Current assignee: Halliburton Co
Priority date: 1958-08-26
Filing date: 1958-08-26
Publication date: 1965-03-16
Anticipated expiration: 1982-03-16

Description

March 16, 1965 s. c. BRETZKE, JR

WELL FORMATION ISOLATION APPARATUS 2 Sheets-Sheet 1 Filed Aug. 26, 1958 Filer Cake FIG. I.

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March 1'6, 1965 s. c. BRETZKE, JR

WELL FORMATION ISQLATION APPARATUS 2 Sheets-Sheet 2 Filed Aug. 26, 1958 r., s. 4 .d m y e s m 9 m m 2. MU @d m u TT w M A H 2 1.. :rn i v 4 .0 M .k m m -`l=n u 7\\\\ m Ww SY m B C 6 G. M M 3 n H 4. G. w F s. u H

Filter Coke United States Patent Cil ce 3,173,485 Patented Mar. 16, 1965 3,173,485 WELL FRMATION ISOLATION APPARATUS Samuel C. Bretzke, Jr., Houston, Text, assigner to Halliburton Company,a corporation of Delaware Filed Aug. 26, 1958, Ser. No. 757,266 6 Claims. (Cl. 16o- 100) This invention generally relates to the testing of earth formations traversed by a well bore and more particularly relates to new and improved apparatus for conducting such testing operations from a hoisting cable.

This invention is particularly suitable for use with apparatus such as disclosed in copending and commonly assigned application to Durward B. McMahan, entitled Well Formation Testing Apparatus, Serial No. 712,190, filed January 30, 1958.

As mentioned in the above copending application, there is an existing need for well formation testing apparatus which may be rapidly and easily lowered into the well bore from a hoisting line and obtain accurate data from well formations which may contain oil and gas in commercial quantities. A pertinent problem in existing wire line tools is that of effecting a good seal between such apparatus and the wall of the well. Failure of the seal results in valueless samples and pressure records of only the drilling fluids.

The hydrostatic uid pressure existing as a result of the weighted drilling fluids in rotary drilled Well bores may be in the order of several thousand p.s.i. The tluid pressure within a particular earth formation traversed by the well bore is always less than this hydrostatic pressure. A sealing member such as herein disclosed is required to effect a seal between the formation and the well bore iiuids to permit fluid entry from the formation to within the testing apparatus. The chambers of such testing apparatus are initially at atmospheric pressure. As the testing apparatus is opened the pressure difference between the well bore and the sample charnber will be exerted across the sealing member as a pressure differential. As fluid low commences from the formation into the testing apparatus the pressure differential across the sealing member becomes the difference in well bore pressure and formation pressure. Such differential pressures in many cases are so great that the sealing member is punctured, allowing fluids to flow directly from the well bore into the testing apparatus. At other times a small initial leakage may exist between the sealing member and the well bore wall which, at the differential pressures existing, will erode channels between the sealing member and formation wall, destroying the value of the test.

It is accordingly the general object of the present invention to provide improved apparatus which, when forced into contact against the wall of a well formation by testing apparatus as described, will effectively seal a portion of such formation from the drilling uids to provide true formation pressures and pure formation uid samples.

This and other objects of the invention are attained by wire line testing apparatus having a well formation tluid isolation member in uid communication and reciprocative connection with a tester body to be selectively extended into physical contact with the Wall of a well formation. The isolation member comprises a support member containing a fluid chamber in fluid connection with a sample chamber defined within said testing apparatus and in connection with a rear face of a resilient pad member. The pad member is provided of resilient material which is provided of predetermined selected resistance to deformation. The front face of the pad member is formed generally complementary to a segment of the well bore wall. A rigid conduit is connected into Huid communication with the support chamber and extends from the support through the` pad member to the front face. A resilient enclosure member of greater resistance to deformation than the pad member is disposed around a selected length of the conduit and in bonded connection with the pad member, forming a portion of said pad face. A screening chamber of smaller volume than the support chamber is disposed within the support chamber and connected in fluid communication with the conduit.

Other objects and advantages of the invention will become more apparent from reference to the following escription taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is an elevational View of the complete testing apparatus suspended in a well bore.

FIGURE 2A is a partial transverse cross section taken at 2-2 of FIGURE 1.

FIGURE 2B is the section of FIGURE 2A taken at a later stage in operation of the device.

FIGURE 2C is the section of FIGURE 2A taken at a further stage in operation of the apparatus.

FIGURE 3A is a longitudinal cross section taken at 3 3 of FIGURE 2A.

FIGURE 3B is the section of FIGURE 3A taken at a later stage in operation of the device.

FIGURE 3C is the section of FIGURE 3A taken at a further stage in operation of the device, and

FIGURE 4 is a front elevation of the formation fluid isolation member shown in FIGURES 1 to 3.

Referring to FIGURE 1, a tester tool 10 is shown suspended in a well bore 12 from a hoisting cable 14. Cable 14 is connected into a hoisting unit (not shown) which is adapted to raise or lower tool 10 to any desired position within a well bore 12. In electrical connection with tool 1t) through cable 14 is a surface operated electrical control and indicating or recording means (not shown).

Tool 10 generally includes three sections, an upper switch housing 16, a testing body 18, and a lower fluid chamber 2t). A spontaneous potential logging electrode 22 is mounted on switch housing 16. Shown at 24 are resilient centralizer arms radially mounted with the body 18 which contact the walls of well bore 12 and tend to keep the tester tool 10 concentrically disposed Within the bore. Body 1S includes the resiliently faced formation isolation member 26 of the present invention and a wicker retaining member 28 jointlymountedl in` reciprocal connection with body 18.

Members

26 and 28 may be connected to body 18 at their upper end by means of longitudinally diverging dove-tail trackways and at their lower ends by means of pins extending into longitudinally diverging slot ways. As illustrated, a transfer rod and crosshead assembly is provided, said transfer rod having spring loaded

pawl arms

30 and 32 mounted thereon in such manner that release of the pawls into contact with the well bore wall and subsequent downward movement of body 18 relative to the transfer assembly will transversely extend

members

26 and 28 out from the testing body 1S into contact With the well bore wall.-

Pawl

arms

30 and 32 and the transfer assembly are provided with electrical Vmeans of selective release. Also provided in the housing 16 are electrical switching means to respectively connect the logging electrode 22 and various valving means disposed in body 18 to the co-nductor 14. While FIGURE 1 discloses sufficient detail of such a tester 10 to clearly point out the operation of the present invention as describedwith respect to FIG- URES 2A and 3A, a more detailed description of the .3 complete construction and Voperation of a tester 10 with which the present invention has been used may be obtained by reference to the previously mentioned copending application.

Transverse and longitudinal sections of isolation member V26 are respectively illustrated in FIGURES 2A and 3A. Isolation member 26 is provided with a support `member 34 which includes a removable cover plate 36. 4Defined within support member 34 is a iiuid chamber 38. Chamber 3S has means of fluid communication into `testing body 18 through a fiuid passageway 40. A seal is provided between cover plate 36 and support member 34 by means of an O-ring42 or the equivalent. Connected in bonded relation to the front of cover plate 36 is a resilient sealing cushion or vpad 44. Though other bonding 'means are possible, pad 44 as herein illustrated is bonded lat its back to plate 36-by vulcanizing.

Connected-through plate 36 into chamber 3% is a fluid sampler barrel or conduit 46. Barrel rigidly extends through an accommodating hole in pad 44 to near the face of the pad. Enclosing the extended portion of barrel 46 and bonded to pad 44 is a sealing enclosure member 48, herein illustrated as being of generally conical configuration diverging toward the face of the pad.

Pad 44 and enclosure member 48 are both provided of resilient and elastic material such as natural or synthetic rubber. For reasons later described, enclosure member 48 is provided of material substantially more resistant to deformation than pad member 44. As an example, pad member 44 may be provided of durometer ranging about 35 to 45 and enclosure member 48 may be provided of durometer ranging about 60 to 80 The term resilient as -used in the appended claims will therefore denote the properties, including resistance to deformation, exhibited by natural or synthetic rubbers.

It is noticed in FIGURE 3A that cover plate 36 is undercut at 5t) above and below barrel 46 to provide clearance between the plate and pad. Though not absolutely esesntiaL this clearance is beneficial in providing increased resilience to the pad about barrel 46 and also providing pressure access to the rear of the pad, as later described.

Connected to the sides of support member 34 and disposed in backing relation to the rear face of pad member 44 are backing members 58. These backing members are usually used only when conducting tests in well bores of large diameter and may be deleted without injurious effect in small bores, for example, of less than 8 inches diameter.

Isolation member 26 is connected into testing body 18 by means of an upper guide 52 and a lower guide 54, shown in FIGURE 3A. As shown, the upper guide 52 is mortised for connection to a complementary dove-tail trackway in testing body 18. Reciprocal connection of member 26 to the transfer member previously mentioned is made with the lug shown at the lower end of guide 54 in FIGURE 3B.

It is seen, from the sections shown in FIGURE 2A, and FIGURE 3A, that the face of pad 44 is of generally arcuate configuration from a longitudinal view and that the face of pad 44 is of radius somewhat smaller than the anticipated radius of the well bore. Also, as shown in FIGURE 3A, the face of the pad is beveled slightly from its center so that initial contact of the pad with the well bore will be made in the immediate vicinity of conduit 46.

Defining four sides of a chamber of smaller dimension within chamber 38 is a screen member 56. Screen 56 is connected with barrel 46 in a manner insuring that all fiuids entering through the barrel must pass through the screen before entering the passageway 49. As shown in FIGURE 2A, the side walls of chamber 3S form the remaining two walls of the chamber defined by screen 56. This arrangement has been found highly beneficial in that, by removal of the cover plate 36, the screen S6 may be withdrawn from chamber 3S and the sand, cuttings or other detritus contained within the screen then removed by merely by allowing such cuttings to fall out the open sides.

In operation, the tester tool 10 is lowered into the well more to an approximate depth indicated by previous electrical logs. The logging electrode 22 is switched into circuit to give surface indication of the spontaneous potential of the adjacent formation. The testing apparatus is then adjusted, by reference to the indication from electrode 22, to the exact depth of the promising formation.

The meanns for releasing

pawl arms

30 and 32 is then switched into circuit and actuated, releasing the arms. The pawl arms, in response to their Spring loading, are then urged into contact in the walls of the well bore, preventing downward movement of the transfer assembly.

The tester tool l() is then lowered by cable 14, causing relative longitudinal movement between the tester body and transfer assembly. The isolation member 26 is urged up the dove-tail having connection with upper guide 52 into contact with the well bore walls.

Such initial contact is illustrated in FIGURES 2A and 3A. It is seen that the drilling mud filter cake may be partially extruded by this initial contact, permitting the inlet of barrel 46 and the face of members 44 and 4S to be in close relation to the bore wall.

The tensions of cable 14 is then released, permitting the entire weight of tester tool 10 to bear, through the illustrated trackways, upon isolation member 26 and wicker member 28. In the embodiment presently illustrated, tool I@ weighs about 385 pounds may be additionally ballasted as required, for example, to 600 pounds or more. It is thus seen that the isolation member is extended into very close and forceful contact with the well bore wall. Such engagement by the full weight of testing tool 1) is illustrated in FIGURES 2B and 3B. It is noticed that enclosure member 48 and a portion of pad 44 have been deformed into intimate contact with the well bore wall. Also, additional drilling mud filter cake may have been extruded from between the pad and the wall. However, a small amount of filter cake may be expected to remain which serves an advantage in filling minute declivities of the well bore wall, which may be somewhat rugose, and in generally serving as a gasketing material between member 26 and the bore wall.

Due to the previously described configuration of the face of member 44, the greatest compression and deformation occurs at the enclosure member 48 and a portion of pad 44 immediately surrounding the enclosure member. It can be seen that the greatest sealing effect occurs in the vicinity immediately about the intake of barrel 46. Depending on the hardness of the formation, the elasticity of the pad member and the Weight of tool 10, the barrel 46 may extend slightly into the formation at this -stage and can be expected to be in contact with the formation.

When provided, the backing members 53 also serve to engage the pad into contact with the well bore wall at this stage of operation. However, as previously described, this baclting feature is not needed for smaller bore sizes and may be deleted in such case.

Since the hydrostatic pressure of the drilling mud or fluids in the well bore is always in excess of the formation fluid pressures, there will always be a pressure differential, often of large magnitude, existing between the well bore and the formation. Thus, when a portion of the formation is isolated by member 26 and fiuid pressure at the entry of barrel 46 is reduced, as by opening a valve to the sample chamber within tester tool 10, this differential pressure is brought to bear across the pad and forces a far more forceful engagement with the well bore wall.

As illustrated in FIGURES 2C and 3C, when fluid communication is provided through barrel 46 into sample chamber 20, the pressure immediately about the intake of barrel 46 initially drops to substantially atmospheric pressure and permits luid flow from the formation through the barrel 46, screen 56 and passageway 40 into sample chamber 20. The well bore fluid pressure is exerted as a differential pressure across the pad 44 and enclosure member 48. As shown, the pad member is pressed against the well bore wall in response to such differential pressure, further deforming the

members

44 and 48 and causing the seal established around barrel 46 to become more positive, particularly at enclosure member 48 and at the pad 44 in the vicinity immediately surrounding member 48.

At this stage of operation the force exerted across the pad member is of suflicient magnitude to cause considerable extension of barrel 46 into the formation. This has been found to be the case even though the formation is hard, impermeable and non-productive.

When in operation adjacent a productive formation the pressure about the intake of barrel 46 rises, as lluid flow begins through the barrel, from the initial atmospheric pressure to the native formation pressure. The previously mentioned differential between the hydrostatic pressure of the well bore fluids and the formation pressure maintain the forceful sealing contact illustrated in FIGURES 2C and 3C.

Enclosure member 48 is provided of material having greater resistance to deformation than does the material of member 44 for two major reasons. One of these reasons, as previously mentioned, is that a superior seal is effected immediately about the intake of barrel 46 upon application of force from the rear of the member 26. A second important reason for provision of these materials as described is to prevent rupture through the pad member in the vicinity of enclosure member 43. In trial tests made during the development of this in vention it was repeatedly found that the structure as disclosed effectively prevented ruptures through the pad formerly caused by the great pressure differential existing between the well bore fluids and the formation.

Though disclosed and illustrated as being generally conical in shape and enclosing very nearly the entire extended portion of barrel 46, enclosure member 43 may be and has been successfully provided of somewhat different configuration. For example, member 48 may be provided in generally cylindrical form for a distance from the plate 36 and then extend in conical fashion as disclosed. Also, enclosure member 48 may be of generally cylindrical configuration throughout its entire length. After many experimental field trials it is believed that the disclosed configuration is superior.

After the complete sampling operation has been performed, the tester tool lil may be withdrawn by taking tension on cable 14. The weight of tester is removed from the

extended members

26 and 28. As tester tool 10 is raised,

members

26 and 28 become free and converge down the dove-tail connections into retracted position. The transfer assembly drops within the tester body 18, permitting withdrawal of the tool 1@ from the well bore. As the tool is withdrawn the

pawl arms

30 and 32 continue to slide against the walls of the well bore 12 but cannot engage when moved in an upward direction.

It is to be understood, while only one embodiment of the invention has been disclosed herein, that various changes may be made without departing from the spirit of the invention. The invention should not be regarded as limited, therefore, except by the scope of the appended claims.

That being claimed is:

l. A well bore lluid isolation member adapted for use with a wireline testing apparatus, comprising, a resilient pad member of material having predetermined resistance to deformation, said pad member having a front and a rear face, a central portion and a hole defined through said central portion between said front and rear face, a support member in connection with a portion of said rear face, said support member being adapted for connection with testing apparatus, said support member defining a fluid chamber adapted for iluid communication with testing apparatus, a `substantial portion of said rear face of said pad member being exposed to pressure of well bore fluids, said front face being Iformed generally arcuate to provide an increasing clearance extending from said central portion between said front face and a well bore wall, a rigid conduit connected to said Support member in fluid communication with said fluid chamber and extending from said support member through said hole to near said front face, a resilient enclosure member of material having greater resistance to deformation that said pad member disposed around a selected length of said conduit and forming an integral portion of said pad member, and a screening chamber of smaller volume than said support chamber disposed within said fluid chamber and in fluid communication with said conduit.

2. A well bore fluid isolation member adapted for use with a wireline testing apparatus, comprising, a resilient pad member of material having predetermined resistance to deformation, said pad member having a front and a rear face, a central portion and a hole dened through said central portion between said front and rear face, a support member in connection with a portion of said rear face, said support member being adapted for connection with testing apparatus, said support member defining a fluid chamber adapted for fluid communication with testing apparatus, a substantial portion of said rear face of said pad member being exposed to pressure of well bore fluids, said front being formed generally complementary to a segment of well bore wall to provide an increasing clearance extending from said central portion between said front face and a well bore wall, a rigid conduit connected to said support member in fluid communication with said fluid chamber and extending from said support member through said hole to near said front face, a resilient enclosure member of material having greater resistance to deformation than said pad member disposed around a selected length of said conduit and forming an integral portion of said front face of said pad mem-ber.

3. A well bore fluid isolation member .adapted for use with a wireline testing apparatus, comprising, a resilient pad member of material having a predetermined resistance to deformation, said pad member having a front and a rear face, a central portion and a hole defined through said central portieri between said front and rear face, a support member in connection with a portion of said rear face, said support member being adapted for connection with testing apparatus, la substantial portion of said rear face of said pad member being exposed to pressure of well bore fluids, said front face being formed generally complementary to a segment of a well bore wall to provide an increasing clearance exten-ding from central portion between said front face and a well bore wall, a rigid conduit connected into said support member and extending from said support member in movable relation through said hole to near said front face, a resilient enclosure member of material having greater resistance to deformation than said pad member disposed around a selected length yof said conduit and forming an integral part of said central portion.

4. A well bore fluid isolation member adapted for use with a wireline testing apparatus, comprising, a resilient pad member of material having predetermined resistance to deformation, said pad member having a front and a rear face, a central portion and a hole defined through said central portion between said front and rear face, a support member in connection with a portion of said rear face, said support member being adapted for connection with testing apparatus, said support member defining a fluid chamber adapted for fluid communications with testing apparatus, a substantial portion of, said rear face of said pad member being exposed to pressure of well bore tluids, said front face being formed generally complementary to a segment of well bore wall to provide an increasing clearance extending from central portion between said front face and a well bore wall, a rigid conduit connected to said support member in fluid communication with said fluid chamber and extending from said support member in movable .relation through said hole to near said front face, a resilient enclosure member of material having greater resistance to deformation than said pad member disposed around a selected length of said conduit and forming an integral portion of said pad member, said enclosure member converging along the length of said hole `from said front face in generally conical shape, and a screening chamber of smaller volume than said support chamber disposed within said fluid chamber and in fluid communication with said conduit.

5. A well bore iluid isolation member adapted for use with a wireline testing apparatus, comprising, a resilient pad member of material having predetermined resistance to deformation, said pad member having a front and a rear face, a central portion and a hole define through said central portion between said front and rear face, a support member in connection with a portion of said rear face, said support member being adapted for connection with testing apparatus, a substantial portion of said rear face of said pad member being exposed to pressure of Well borc iiuids, a rigid conduit connected into said support member and extending from said support member through said hole to near said front face, a resilient enclosure member of material having greater resistance to deformation than said pad member disposed around a selected length of said conduit and forming an integral portion of said central portion.

6. A well bore fluid isolation member adapted for use with a wireline testing apparatus, comprising, a resilient pad member of material having predetermined resistance to deformation, said pad member having a front and a rear face, a central portion and a hole defined through said central portion between said front and rear face, a support member in connection with a portion of said rear face, said support member being adapted for connection with testing apparatus, said support member defining a fluid chamber adapted for fluid communication with testing apparatus, a substantial portion of said rear face of said pad member being exposed to pressure of well bore iiuids, a rigid conduit connected to said support member in fluid communication with said fluid chamber and extendin from said support member through said hole to near said front face, a resilient enclosure member of material having greater resistance to deformation than said pad member disposed around a selected length of said conduit and forming an integral portion of the central poriton of said pad member, and a screening Chamber of smaller volume than said support chamber disposed within said uid chamber and in said uid communication with said conduit.

References Cited in the tile of this patent UNITED STATES PATENTS

Claims

2. A WELL BORE FLUID ISOLATION MEMBER ADAPTED FOR USE WITH A WIRELINE TESTING APPARATUS, COMPRISING, A RESILIENT PAD MEMBER OF MATERIAL HAVING PREDETERMINED RESISTANCE TO DEFORMATION, SAID PAD MEMBER HAVING A FRONT AND A REAR REAR FACE, A CENTRAL PORTION AND A HOLE DEFINE THROUGH SAID CENTRAL PORTION BETWEEN SAID FRONT AND REAR FACE, A SUPPORT MEMBER IN CONNECTION WITH A PORTION OF SAID REAR FACE, SAID SUPPORT MEMBER BEING ADAPTED FOR CONNECTION WITH TESTING APPARATUS, A SUBSTANTIAL PORTION OF SAID REAR FACE OF SAID PAD MEMBER BEING EXPOSED TO PRESSURE OF WELL BORE FLUIDS, A RIGID CIRCUIT CONNECTED INTO SAID SUPPORT MEMBER AND EXTENDING FROM SAID SUPPORT MEMBER THROUGH SAID HOLE TO NEAR SAID FRONT FACE, A RESILIENT ENCLOSURE MEMBER OF MATERIAL HAVING GREATER RESISTANCE TO DEFORMATION THAN SAID PAD MEMBER DISPOSED AROUND A SELECTED LENGTH OF SAID CIRCUIT AND FORMING AN INTEGRAL PORTION OF SAID CENTRAL PORTION.