US3459261A

US3459261A - Pressure differential expanding means for well packers

Info

Publication number: US3459261A
Application number: US513465A
Authority: US
Inventors: Chudleigh B Cochran
Original assignee: Brown Oil Tools Inc
Current assignee: Hughes Tool Co; Baker Hughes Holdings LLC
Priority date: 1965-12-13
Filing date: 1965-12-13
Publication date: 1969-08-05
Anticipated expiration: 1986-08-05

Description

a- .1969 c. a. COCHRAN 3,459,261

PRESSURE DIFFERENTIAL EXPANDING MEANS FOR WELL PQCKERS Filed Dec. 13, 1965 3 Sheets-Sheet 1 lji v ,4

Aug. 5, 1969 c. B. COCHRA N 3,459,251

I PRESSURE DIFFERENTIAL EXPANDING MEANS FOR WELL PAcKsRs Filed Dec.13,.1965 3 Sheets-Sheet 2 cuuamsy (0mm \fi INVENTOR.

l 4BY 6 W I ORNEy 5, 1969 4 c. a. COCHRAN 3,459,261

PRESSURE DIFFERENTIAL EXPANDING MEANS FOR WELL PACKERS Filed Dec. 13, 1965 3 Sheets-Sheet 3 CHUDL 5/6 5 (We/IRAN 4 I N VEN TOR.

' z lw/w A TTORNE/S United States Patent Oflice 3,459,261 PRESSURE DIFFERENTlAL EXPANDING MEANS FOR WELL PACKERS Chudleigh B. Cochran, Houston, Tex., assignor to Brown Oil Tools, Inc., Houston, Tex., a corporation of Texas Filed Dec. 13, 12965, Ser. No. 513,465 Int. Cl. E21b 33/126 US. Cl. 166-120 1 Claim ABSTRACT OF THE DISCLOSURE A well packer including a packing element mounted on a slidable sleeve between abutments with the sleeve being responsive to pressure differentials from both directions to increase the endwise compression on the packing element.

The present invention relates to new and useful improvements in well packers.

In the past, well packers which have been exposed to very high-pressure differentials across the packing element have had a tendency to leak. It is believed that this leakage results from the fact that the high pressures exceed the compression of the packing element and can, thereby, form a fluid pressure wedge between the packing element and the interior of the pipe against which the packing element seals.

The present invention provides a well packer having a pressure responsive means to increase the compressive load on the packing element responsive to a pressure differential across the packing element.

It is, therefore, an object of the present invention to provide an improved well packer in which pressure differentials held by the packing element are utilized to increase the longitudinal compression of the packing element to maintain the seal of the packing element.

Another object is to provide an improved well packer which will not leak under conditions of very high-pressure differential.

Still another object is to provide an improved well packer utilizing the pressure differentials across the packing element to increase the compression forces applied to the packing element and thereby avoid the aforementioned high-pressure leakage.

A further object is to provide a well packer with a pressure-responsive means to multiply the pressure forces on the packing element and thereby enable the packing element to remain sealed at very high-pressure differential.

The construction designed to carry out the invention will be hereinafter described, together with other features thereof.

The invention will be more rapidly understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

FIGURE 1 is a partial sectional view illustrating the well packer of the present invention with the various parts of the packer being shown in the position for lowering the apparatus within a well bore;

FIGURE 2 is a similar view illustrating the well packer in set position;

FIGURE 3 is a view of the well packer in set position when exposed to pressure differentials from below the packing element;

FIGURE 4 is a similar view of the well packer in set position and exposed to pressure differentials from above; and

FIGURE 5 is another similar view of the well packer illustrating its released position.

Referring to FIGURE 1, the well packer of the present invention is shown in its running-in position as it is being 3,459,261 Patented Aug. 5, 1969 lowered on the tubing string T within the Well casing C. The well packer includes the tubular support or mandrel 10 on which the upper abutment 12 and the lower abut ment 14 are mounted with the anchoring assembly A, packing assembly P and the setting assembly S also mounted thereon between said abutments. The tubular support 10 is connected to the tubing string T by collar 16. The connecting threads 18 between the tubular support 10 and the collar 16 provide the releasing means for the packer and are special threads, preferably a left-hand, low friction-type of threads to assure operation of the release function of such connection, as hereinafter set forth.

The upper abutment 12 includes the ring 20 having an inwardly projecting flange 22 which closely surrounds the exterior of the collar 16. The lower end of the collar projects outwardly to provide the upwardly facing shoulder 24. Bearing rings 26 are positioned around the collar 16 between its upwardly facing shoulder 24 and the flange 22 on the ring 20 to limit the friction during release. The main abutment body 28 is threadedly secured to the ring 20 with the locking ring 30 and the bearing ring 32 positioned to maintain the aforementioned components of the upper abutment in fixed relation longitudinally with respect to the collar 16 while allowing relative rotation of the collar 16 with respect to the upper abutment. The body 28 surrounds the tubular support 10 and is spaced therefrom to provide a recess surrounding the tubular support 10 for movement of part of the packing assembly therein.

The packing assembly P is mounted on tubular support 10 immediately below the upper abutment 12. It includes the upper packing follower 34, the lower packing follower 36, the plastic packing element 38, all mounted in surrounding relationship to the pressure-responsive means or packing sleeve 40 and between the engaging means or outwardly projecting upper and

lower flanges

42 and 44 on the sleeve 40. Additionally, the upper follower 34 is interengaged with the upper abutment 12 by connecting means which includes the interengaging

flanges

46 and 48. The flange 48 is spaced a greater distance from the body 28 of the upper abutment than the thickness of the flange 46, and the flange 46 is spaced from the remainder of the follower 34 by a greater distance than the thickness of the flange 48 to allow move-ment of follower 34 relative to body 28. Additionally, the upper end of the follower 34 is provided with the slot 50 to allow pressure to be exerted over this portion of the follower 34. The packing sleeve 40 is generally tubular in shape and provided with sealing means, such as packing ring 52, which seals between the interior of the packing sleeve 40 and the exterior of the mandrel 10 at a position below the snap ring 54. The snap ring 54 is positioned in a groove around the exterior of mandrel 10 but does not engage the interior surface of the packing sleeve 40 so that the packing sleeve 40 is free to move longitudinally with respect to the mandrel 10 and the upper abutment 12.

The anchoring assembly A is interconnected with the packing assembly P by a connecting means which includes the flange 56 on the lower packing follower 36 and the flange 58 on the upper anchoring expander 60. The flange 58 is spaced from the upper end of the expander 60, and flange 56 is spaced from follower 36 to provide a distance in which the follower 36 may move with respect to the upper expander 60. Additionally, the lower end of the follower 36 is provided with the slot 57 to allow pressure to be exerted against the lower side of follower 36.

The anchoring assembly is positioning around tubular support 10 immediately below the packing assembly P. The anchoring assembly A includes the upper and

lower expanders

60 and 62 and the gripping elements 64. The gripping elements 64 are made in two sections with the usual T connection 66 therebetween. The upper gripping sections are each provided with a pin 68 which extends therethrough into a slot 70 in expander 60. Additionally, the lower sections of the gripping elements 64 are each provided with a pin 72 which extends therethrough and projects into a slot 74 in the lower expander 62. Each of the sections of the gripping elements 64 is provided with dove-tail projections 76 to engage in the dove-tail slots 78 in the

respective expanders

60 and 62. The ex- 7 terior of the tubular support is provided with the snap ring 80 positioned in a groove and extending outwardly therefrom. The snap ring 80 is adapted, as hereinafter explained, to engage in the recess 82 in the upper end of the lower expander member 62.

The setting means S illustrated for the packer is a pressure-responsive means. The fluid pressure is conducted to the pressure-responsive means from the interior of the tubular support 10 through the port 84. The pressureresponsive means includes the sleeve 86, the piston ring 88 and the sealing ring 90. The sealing ring 90 immediately surrounds the exterior of the mandrel 10 and rests on the lower abutment 14 to provide a seal between sleeve 86 and tubular support 10. In the running-in position, the sleeve 86 is connected to the ring 90 by the shear pin 92 and is connected to the lower expander 62 by the pin 94. Suitable sealing means is provided on the inner and outer surfaces of the piston 88 and the ring 90 to contain the fluid pressure therebetween during setting.

A suitable locking means 96 is provided in the form of locking slips which are positioned under the tapered surface of the lower expander 62 and have their toothed surface in engagement with the exterior of the tubular support 10. The lower end of the locking means 96 abuts the upper end of the piston 88. The teeth on the locking slips are directed downwardly whereby the slips will have very little resistance to upward movement with respect to the tubular support 10 and will prevent a downward movement of the lower expander 62 with respect to the tubular support 10 to thereby assure that the setting means S when set will be held in such set position.

The lower abutment 14 supports the ring 90 and includes the abutment ring 98 which is secured to the exterior of the tubular support 10 by the snap rings 100 and 102. The seat 104 is provided in the lower end of tubular support 10 to receive the setting ball 106 or other suitable device for the setting operation of the well packer.

In operation, the well packer with the components positioned as illustrated in FIGURE 1 is lowered on the tubing string T into the well casing C to the position at which the well packer is to be set. Thereafter, the setting ball 106 is dropped through the tubing string T and seats on the seat 104 in the lower end of the tubular support 10. With the setting :ball 106 in position, the tubing string T is pressured up with a suitable fluid, normally hydraulic fluid. This fiuid pressure is conducted through the port 84 and urges the piston ring 88 upwardly. The initial movement of the piston ring 88 moves the locking slips 96 upwardly until the upper surface of the piston ring 88 engages the lower surface of the lower expander 62. Thereafter, when sufficient pressure is exerted against the piston ring 88 to shear the pin 92, the piston ring 88, the sleeve 86, the locking means 96 and the lower expander 62 move upwardly as a unit. This upward movement is translated through the anchoring assembly A to compress the packing assembly P into set position. The compression of the packing assembly P is accomplished by the upward force exerted by the upper expander 60 against the lower follower 36, which force provides an end-wise compression of the packing element 38 between the

followers

34 and 36 with the upper abutment 12 holding the follower 34 to cause the packing element 38 to expand radially outward into set position with the well casing C. The upper follower 34 will be in abutting relation to the upper abutment 12 to provide the resistance necessary to create the setting forces for the packing assembly. Thereafter, continued upward movement of the piston 88 moves the

expander members

60 and 62 toward each other to thereby force the gripping element 64 outwardly into pipe-gripping position with the wall of the well casing C to complete the setting of the packer.

When the well packer is in set position and is exposed to large pressure differentials from beneath the packing element, the pressure differential is exerted on the lower end of the packing sleeve member 40 and also on the lower side of the packing follower 36. This condition is illustrated in FIGURE 3. Since in set position room is provided for upward movement of both the sleeve 40 and the packing follower 36, this pressure is exerted on the total annular area between the exterior of tubular support 10 and the interior of well casing C to create a force which further compresses the packing element 38. This pressure force created is greater than the force of the pressure on the packing element since this pressure force results from pressure on the annular area of the sleeve and the annular area of the packing element.

Additionally, the same action occurs when the well packer is set and is exposed to high-pressure differentials from above. This condition is illustrated in FIGURE 4. Such pressure differential is transmitted through the port 108 in the abutment body 28. In this manner, the upper pressure is exerted on the total annular area between the exterior of the tubular support 10 and the interior of the casing C. The sleeve 40 moves downwardly until its flange 42 engages the upper end of the follower 34. Thereafter, the pressure force on the sleeve 40 is transmitted through the follower 34 to the packing element 38 to thereby increase the setting force of the packing element 38.

This increase in setting force resulting from pressures both above and below over a larger area than the exposed area of the packing element 38 creates a compressive force in the packing element which is sufiicient to prevent the aforementioned high-pressure leakage. In each case where the pressure differentials held by the packing assembly approach the possible high-pressure leakage point of the packing element, such pressure differentials are utilized to increase the setting load on the packaging to assure the maintenance of the packing seal. Thus, the greater the pressure load on the packing, the greater the setting force on the packing will be multiplied to hold the packing sealed. This mechanical advantage assures the maintenance of the seal at all times.

The release of the well packer is accomplished by rotation of the tubing string T in a clock-wise or right-hand direction. This rotation actuates the threaded connection 18 to initially cause the tubular support 10 to move down- Ward. Since a special threaded connection is used, the rotation of the tubing string does not unthread any other connection and thereby assures that the release functions properly. As the tubular support 10 moves downwardly, the snap ring engages in the recess 82 to exert a downward force on the lower expander 62. The downward movement of the lower expander 62 retracts the lower section of the gripping element 64 from engagement with the well casing C until the pin 72 engages the upper end of the slot 74. Thereafter, further downward movement is prevented since the upper section of the gripping elements is held in engagement with the well casing C. Further rotation of the tubing string causes the upper abutment 12 to be moved upward to relax the packing assembly P. The engagement of the

flanges

46 and 48 and the engagement of the flange 42 with the upper surface of the upper follower 34 raises the follower 34 and the sleeve 40 upward with the upward movement of the upper abutment 12. As soon as the flange 44 0f the sleeve 40 engages the lower side of the lower follower 36, the packing assembly P is completely released and sleeve 40 moves the follower 36 upward until its flange 56 engages the flange 58 on the upper expander 60. Continued upward movement of these elements withdraws the upper expander 60 from under the upper section of the gripping element 64 to thereby complete the retraction of the gripping elements 64 and thus efiect complete release of the device. During release of the well packer assembly, the port 110 which extends through collar 16 is uncovered by the downward movement of tubular support 10. The port 110 will allow fluid pressures above the packing element to be equalized through the tubular support during release and also during removal of the well packer from the well bore.

From the foregoing it can be seen that the well packer of the present invention provides an improved packing assembly which will maintain its seal under extremely high-pressure differentials by utilizing such pressure differentials over an annular area larger than the annular area of the packing element to increase the setting force on the packing element. This improved packing assembly structure assures that the packing seal will be maintained under all pressure conditions.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claim without departing from the spirit of the invention.

I claim:

1. A well packer, comprising:

a tubular support,

an upper abutment and a lower abutment mounted in spaced relation on said tubular support,

an anchoring assembly on said tubular support support between said abutments,

setting means on said tubular support and including:

means defining a pressure chamber surrounding said tubular support,

a pressure responsive piston slidably mounted around said tubular support in said pressure chamber, and

means for conducting pressure from the interior of said tubular support to said pressure chamher,

said pressure responsive piston coacting with one of said abutments whereby movement of said piston responsive to pressure in said pressure chamber moves said packing assembly and said anchoring assembly to set position, and

a packing assembly mounted on said tubular support between said abutments and including:

a plastic packing element adapted when compressed to extend radially outward into set position, and pressure responsive means mounted on said tubular support and coacting with said packing element to exert a compressive force on said packing element responsive to a pressure differential held by said packing element, said pressure responsive means including:

a sleeve surrounding said tubular support and slidable thereon responsive to pressure around said tubular support,

means sealing between said sleeve and said tubular support,

said packing element being mounted around said sleeve,

upper and lower packing followers mounted around said sleeve above and below said packing element,

means on said sleeve engaging said upper packing follower when said sleeve is in its lower position,

means on said sleeve engaging said lower packing follower when said sleeve is in its upper position,

a locking means coacting between said piston and said tubular support to allow setting movement of said piston with respect to said tubular support and to prevent reverse movement of said piston with respect to said tubular sup-port, and

means threadedly connecting the tubular support to the other of said abutments whereby rotation of said tubular support increases the axial distance between said abutments to release said anchoring assembly and said packing assembly from set position.

References Cited UNITED STATES PATENTS 3,180,419 4/1965 Cochran et a1 166--12O 3,211,227 10/1965 Mott 166120 3,223,169 12/1965 Roark 166-120 3,339,637 9/1967 Holden 166120 3,391,740 7/1968 Edwards 166-120 3,394,762 7/1968 Young 166134 JAMES A. LEPPINK, Primary Examiner US. Cl. X.R. 166-131, 182