Mechanism for use in a well bore

Feb. 14, 1967

E. L. MEDFORD, JR

3,303,884

MECHANISM TO BE ACTUATED FORCE TRANSMITTING MECHANISM ^! ACTUATING MECHANISM

MECHANISM FOR USE IN A WELL BORE

Filed Oct. 19, 1964

Sheets-Sheet 1

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BY

ATTORNEYS

Feb. 14, 1967

E. L. MEDFORD, JR

3,303,884

MECHANISM FOR USE IN A WELL BORE

Filed Oct. 19, 1964

Sneets-Sheet 2

<img file="US3303884A_D0002.tif" />

United States Patent Office

Patented Feb. 14, 1967

3,303,884

MECHANISM FOR USE IN A WELL BORE

Erskin L. Medford, Jr., Duncan, Okla., assignor to Halliburton Company, Duncan, Okla., a corporation of Delaware

Filed Oct. 19, 1964, Ser. No. 404,894

Claims. (Cl. 166—63)

This invention relates to a mechanism for use in a well bore. In particular, it relates to a force transmit- ₁₀ting mechanism adapted to effect the efficient actuation of apparatus such as packers.

A variety of setting tools have heretofore been developed to facilitate the setting or actuation of devices such as packers within a well bore in response to a set- 15 ting force remotely generated within the well bore. In general, however, such setting mechanisms have not made the most effective utilization of the available setting force during portions of the apparatus setting cycle when different levels of force could be most efficiently employed. 20 In addition, previously known setting tools have often failed to cause movable, apparatus setting members to move at the most effective rates during portions of the apparatus setting or actuating cycle.

It is an object of the present invention to provide ap- 25 paratus which, in response to available force, effectively varies this force during the cycle of setting an apparatus within a well bore to obtain improved efficiency.

A related, principal object of the invention is to provide such an apparatus which varies the rate of move- 30 ment of apparatus setting or actuating members during a setting cycle so as to obtain improved setting efficiency.

A more specific object of the invention is to provide an apparatus for use in a well bore which, in response to force remotely generated within a well bore, applies 35 a relatively low setting force to an apparatus during the portion of the setting cycle when relatively low force is required and which applies relatively greater setting force when relatively greater force is required.

A similar, more specific object of the invention is to 40 provide an apparatus for use within a well bore which, in response to a force remotely generated within the well bore, causes a movable apparatus setting or actuating member to move at a relatively rapid rate during the first portion of the setting cycle where a low setting force is required and to move at a relatively slower rate during a later portion of the setting cycle when greater setting force is required.

It is also an object of the invention to provide such apparatus which may be so configured as to have mov- ₅q able components exposed to the pressure of well bore fluids but which components may remain substantially pressure balanced and not adversely affected by such pressure.

A still further object of the invention is to provide a 55 fluid, force transmitting coupling between components of a force transmitting mechanism which may be automatically supplied from well bore fluids as the mechanism is lowered into a well bore.

In order to accomplish the foregoing objectives, there θ₀is presented through this invention an apparatus for use in a well bore which includes force generating means having actuating means and which is operable within a well bore to move the actuating means. The apparatus may further include a mechanism to be actuated within g₅the well bore. Force transmitting means included in the apparatus are operatively disposed between the actuating means and the mechanism to be actuated. The force transmitting means includes first means movable in response to movement of the actuating means and γθ second means movable in response to movement of the first means and adapted to actuate the mechanism. Cou pling means included in the force transmitting means operably connect the first and second means. The coupling means is adapted to cause the second means to initially move at a first rate more rapid than the rate of movement of the first means and thereafter move at a second rate slower than the first rate. The second means, while moving at the second rate, transmits greater force to the mechanism than, when moving at the first rate.

A particularly significant and independent aspect of the invention resides in the particular structure of a force transmitting means. This structure comprises first piston means and second piston means having at least first and second, fluid reactive, piston head areas. Coupling means operatively connecting these piston means comprise first cylinder means in which the first piston means is slidably received. The coupling means further includes second cylinder means in fluid communication with the first cylinder means and in which the second piston means is slidably received. The second cylinder means has a first portion adapted to expose only the first, fluid reactive, piston head area of the second piston means to the pressure of fluid urged by the first piston means from the first cylinder means into the second cylinder means during one portion of the movement of the second piston means. The second cylinder means further includes a second portion which is adapted to expose both the first and second, fluid reactive, piston head areas of the second piston means to the pressure of fluid moved by the first piston means from the first cylinder means into the second cylinder means during another portion of the movement of the second piston means. One of the piston means is adapted to move in response to a force applied thereto within a well bore. The other of the piston means is adapted to transmit force to means to be actuated within the well bore.

In describing the invention reference will be made to a preferred embodiment shown in the drawings.

In the drawings:

FIGURE 1 provides a partially sectioned, schematic, vertical elevation view of an apparatus to be actuated within a well bore, which apparatus includes a setting portion, a force transmitting portion, and a radially expansible packer portion. FIGURE 1 illustrates the portions of the apparatus prior to the setting of the packer portion;

FIGURE 2 schematically illustrates the portions of the FIGURE 1 apparatus during the initial part of the setting of the packer portion;

FIGURE 3 schematically illustrates the disposition of the components of the FIGURE 1 apparatus during the terminal part of the setting of the packer portion;

FIGURE 4 provides an enlarged, sectioned, vertical elevational view of operating components of the force transmitting portion of the apparatus shown in FIGURE 1;

FIGURE 5 is a cross sectional view of the FIGURE 4 assembly as viewed along the section line 5—5;

FIGURE 6 is a cross sectional view of the FIGURE 4 assembly as viewed along the section line 6—6;

FIGURE 7 is a cross sectional view of the FIGUPJi 4 assembly as viewed along the section line 7—7; and

FIGURE 8 is a fragmentary, schematic view of a portion of the FIGURE 4 assembly illustrating representative increments of movement of one annular piston corresponding to and resulting from increments of movement of another annular piston.

FIGURE 1 illustrates an apparatus which includes as its principal components a force generating or setting tool portion 1, a force transmitting portion 2, and a mechanism to be actuated, i.e., packer portion 3.

As illustrated in FIGURE 1, the overall apparatus may

3,303,884 be supported within, a well bore 4 by a cable 5 which extends to a hoist mechanism at the ground surface.

The schematically illustrated setting tool 1 includes a cylinder 6. This cylinder has an upper portion 6a which houses an explosive charge 7 and a lower portion 6b which houses a piston 8. A conventional, explosive charge igniting, electrical device 9 may be mounted in cylinder head 6c and actuated by an electrical signal transmitted through cable 5. The actuation of ignition device 9 causes the detonation of the explosive charge 7 which generates pressurized gas. This gas, in a well recognized fashion, will force piston § axially downwardly.

Packer portion 3, as schematically illustrated, may include upper slips 10, upper slip expanding blocks 11, lower slips 12, and lower slip expanding blocks 13. Slip expanding blocks 11 and 13 may function as abutments engaging the upper and lower ends, respectively, of a radially expansible, resilient, and annular packer assembly 14.

Slips 10 and 12, expander blocks 11 and 13, and the annular packer assembly 14 are slidably supported on a mandrel-like, central support 15. An enlarged end 15α of mandrel 15 provides an annular abutment surface 15b which engages the underside of the lower slips 12 as schematically shown.

As will be apparent, the imposition of converging forces on slips 10 and 12 will tend to cause these slips to move generally radially outwardly while convering toward each other so as to engage the wall of the well bore 4. These forces will further tend to cause the radial expansion of the packer assembly 14 into sealing engagement with this well bore wall.

For purposes of illustration, mandrel 15 is shown as extending through the force transmitting portion 2 of the apparatus and as being connected with the cylinder 6 of the setting tool 1.

Mandrel 15 is connected by an annular shoulder 16 to sleeve means 17. This sleeve means, which is coaxially related to mandrel 15, has an upwardly directed sleeve portion 18 extending from shoulder 16 and a downwardly directed sleeve portion 19 extending from shoulder 16.

As shown in FIGURES 4 and 5, sleeve portion 18 is of uniform inner diameter and is radially spaced from the uniform outer diametered mandrel 15 so as to define an upper or first, annular cylinder 20. An annular piston 21 is slidably received within the cylinder 20 and may be connected by a cross-link 22 to a piston rod 23. Piston rod 23 extends downwardy from the setting tool piston 8. Cross-link 22 extends through longitudinal slots 15c and 15d in mandrel 15 so as to be axially or longitudinally slidable and to be able to transmit longitudinal downward movement of the piston 8 through the wall of mandrel 15 to the piston 21.

As shown in FIGURES 4 and 6, sleeve portion 19 includes an upper portion 24 of uniform inner diameter which is radially spaced from mandrel 15 so as to define an upper or first, annular portion 25 of a second or lower, annular cylinder 26. As shown in FIGURES 4 and 7, lower portion 27 of sleeve portion 19 has a uniform inner diameter exceeding the inner diameter of sleeve portion 24. Sleeve portion 27 is radially spaced from mandrel 15 and is connected to sleeve portion 24 so as to define a second or lower portion 28 of second cylinder 26 which communicates with and defines an extension of the upper cylinder portion 25. In the illustrated arrangement, the inner diameter of sleeve portion 27 is the same as the inner diameter of sleeve portion 18.

A series of circumferentially spaced, longitudinally extending passages 29, formed in shoulder 16, provide communication between the first cylinder 20 and the upper or first portion 25 of the second cylinder 26. FIGURE 5 illustrates a representative arrangement of these passages in cross section.

A second annular piston 30 is slidably disposed in second cylinder 26. Piston 30 includes an upper or first portion 31 which slidably and sealingly engages the upper cylinder portion 25. Second piston 30 additionally includes a second or lower portion 32 which slidably and sealingly engages second portion 28 of second cylinder 26 and is connected with first piston portion 31.

With the cylinder 20, passages 29, and cylinder portion 25 above piston portion 31 filled with fluid, the pistons 21 and 30 will be in fluid coupled, force transmitting relationship. Downward movement of the piston 21, caused by the explosively induced downward movement of the piston 8, will thus induce downward movement of the piston 31.

The axial length of second portion 28 of the lower cylinder 26 exceeds the axial length of the upper piston portion 31. Thus, the upper piston portion 31 of the second piston 30 will leave the upper cylinder portion 25 and enter the lower cylinder portion 28 during the downward movement of the piston 30.

As will be apparent, the first portion 25 of second cylinder 26 exposes only the upper or first piston portion 31 to the pressure of fluid moved by the first piston 21 through the passages 29 into the cylinder portion 25 while the piston portion 31 remains in sealing engagement with the cylinder portion 25. When the piston portion 31 has moved axially downwardly out of the cylinder portion 25 and into the cylinder portion 28, both piston portion 31 and piston portion 32 are exposed to the pressure of fluid moved by the piston 21 through the passages 29 into the cylinder 26.

Piston 31 will have a fluid reactive, piston head area equal to its annular cross sectional area, i.e., the cross sectional area of the cylinder portion 25. Thus, with piston 31 in cylinder portion 25, the piston 30 will have an effective fluid reactive area equal to the cross section of cylinder 20. Piston portion 32 will have an effective, fluid reactive, piston head area equal to its annular cross sectional area less the annular, cross sectional area of the piston portion 31. In other words, the effective fluid reactive, piston head area of the piston portion 32 will equal the cross sectional area of the annular space between the outer wall of the piston portion 31 and the inner wall of the sleeve portion 19. With piston 31 moved into cylinder portion 28, the effective fluid reactive area of the piston 30 will be equal to the cross sectional area of the piston portion 32, i.e. cylinder portion 28 which, of course, is equal to the combined, piston head areas of the piston portions 31 and 32.

As shown in FIGURE 8, the initial movement of piston 21 through the increment X, caused by the explosively induced downward movement of the piston 8, piston rod 23, and cross-link 22, will result in movement of the piston 30 through a corresponding but larger increment Y. The ratio of increment Y to the increment X will be proportional to the ratio of the cross sectional area of the cylinder 20 to the cross sectional area of the cylinder portion 25.

After the piston 30 has moved downwardly a sufficient degree so as to enable the piston portion 31 to leave the cylinder portion 25 and enter the cylinder portion 28 as shown in FIGURE 8, each increment of movement M of the piston 21 will be accompanied by a corresponding and equal increment of movement N of the piston 30. These equal rates of piston movement in the illustrated embodiment result from the equal cross sectional areas of the annular cylinder 20 and annular cylinder portion 28.

An annular, sleeve-like portion 33 of piston 32 projects downwardly from piston 32 and terminates in an enlarged lower end 34. End 34 provides an annular abutment shoulder 34α which engages the upper end of the upper slips 10. Abutment 34α moves downwardly, relatively to mandrel 15, in response to relatively downward movement of piston 8 so as to cause the previously noted packer setting convergence of the expander blocks 11 and 13 and the slips 10 and 12. However, owing to the differences in effective, fluid reactive, piston head areas of the second piston 30 during the initial and terminal portions of the downward movement of this piston, the initial convergence of the abutments 34α and 150, as shown in FIGURE 2, will occur at a relatively rapid rate with relatively

3,303,884 low applied force while the terminal portion of this converging movement will occur at a relatively slow rate but with a greater relatively applied force. Thus, during the initial part of the packer setting, where little resistance to slip setting and packer expansion is encountered and where the packer components are most freely movable, the packer components are moved at an efficient, relatively fast rate with an attendant relatively low applied force. During the terminal part of the setting operation shown in FIGURE 3, where greater setting force is required, i.e. where it is necessary to expand the packer into tight fitting sealing engagement with a well bore wall, the packer components are moved with maximum applied force but at an attendant relatively slow rate.

As shown, annular piston 21 projects upwardly out of the upper open end of cylinder 20 so as to extend upwardly away from the passages 29 and be subject to the pressure of well bore fluids surrounding the apparatus. Similarly, sleeve portion 33 of piston portion 32 projects downwardly out of the lower open end of cylinder 26 so as to project downwardly away from the passages 29 so that piston 30 will also be subject to the pressure of well bore fluid surrounding the apparatus.

Where, as in the illustrated embodiment, sleeve portions 18 and 19 are of uniform and the same diameter, the cross sectional areas of cylinder portions 20 and 28 will be the same. In these instances the portions of the pistons 21 and 30, which are subject to the pressure of well bore fluid, will have the same effective fluid reactive areas exposed to well bore fluids. As a result, the pressure of well bore fluid exerted on the upper and lower ends of the pistons 21 and 30, respectively, will have a substantially counter-balancing effect on these fluid coupled pistons. While the difference in elevation of the pistons 21 and 30 will provide some net, upward force resulting from the hydrostatic pressure of the well bore fluids, this upward force will be of relatively minor consequence.

Prior to describing the overall mode of operation of the apparatus, specific structural details of the force transmitting apparatus portion 2 which are not illustrated in FIGURE 1 should be discussed with reference to FIGURE 4.

FIGURE 4 illustrates a representative manner in which the sleeve means 17 may be associated with the mandrel 15 so as to provide the annular cylinders 20 and 26.

As shown in FIGURE 4, sleeve 17 is provided with the radially inwardly directed, annular shoulder 16. Shoulder 16 has an internally threaded coupling portion 35 which is threadably engaged with an externally threaded coupling portion 36 formed on mandrel 15. An annular, radially outwardly projecting mandrel shoulder 27 provides an abutment surface against which the lower edge of the shoulder 16 may come to rest, and thus be secured. As illustrated, the passages 29 may extend below the shoulder 16 and partially into the wall of the body of the mandrel 15 so as to terminate in communication with an annular opening 38 which defines the uppermost portion of the upper portion 25 of the lower annular cylinder 26.

In order to insure that the pistons 21 and 30 remain in fluid coupled relationship and are not adversely influenced by the pressure of well bore fluids surrounding the apparatus, check valve means are incorporated in the apparatus. Such check valve means are adapted to allow well bore fluids to flow into each of the cylinders 20 and 26 and are further adapted to prevent an outflow of fluid from these cylinders.

As shown in FIGURE 4, in the preferred embodiment of the force transmitting mechanism 2, the check valve means comprise first and second check valves 39 and 40 which comprise portions, respectively, of the pistons 21 and 30.

As shown in FIGURE 4, check valve 39 comprises an annular support ring 41 to which is secured, by conventional means, a generally annular and resilient, flexible seal 42. Seal 42 may be fabricated of resilient material such as rubber or neoprene. Seal 42 includes a cylindrical portion 42α which is secured to the supporting ring 41 and a free-lip portion 426 having a generally downwardly converging, frustoconical configuration. As illustrated, the lip portion 42h wipingly and sealingly engages the outer surface of the mandrel 15. Support ring 41 may be secured in an annular notched portion 43 on the lower end of piston 21 by conventional fastening means not shown.

As illustrated, valve 39 is so mounted that the cylindrical portion 42α of flexible seal 42 is slightly radially spaced from the outer periphery of the mandrel 15. As will be further noted by reference to FIGURE 4, the inner surface of the piston 21 may be substantially aligned with the inner surfaces of the seal portion 42α and the supporting ring 41 so as to define an annular channel 44 which is sealed from the cylinder 20 below the head of piston 21 only by the lip portion 42b of the flexible seal 42. One or more radially extending ports 45 may be provided which intersect the wall of the annular piston 21 so as to communicate with the passage 44. In this fashion, a circuit of fluid communication between the cylinder 20 and the exterior of the mechanism 2 is provided, with flow through this passage being controlled by the check valve functioning, seal lip portion 42b. As will be appreciated, with the downwardly converging frustoconical configuration of the seal lip portion 426, fluid will be prevented from flowing out of the cylinder 20 by the seal lip 42b while fluid from the exterior of the tool may flow into the interior of the cylinder 20 when the pressure of the well bore fluid exceeds that of the coupling fluid contained within the cylinder 20. It will be apparent, of course, that fluid which enters the cylinder 20 may also flow through the passages 29 so as to fill the upper portion 25 of the lower cylinder 26 if necessary.

Lower check valve 40 is structurally and functionally similar to upper check valve 39 and includes an annular support ring 46 and an annular, flexible and resilient seal 47 which may be fabricated from material such as rubber or neoprene. Seal 47 includes a cylindrical portion 47α which is secured to support ring 46 and an upwardly diverging, free lip portion 47b which extends from the top of the seal portion 47α into wiping and sealing engagement with the inner wall of the sleeve portion 27.

As illustrated, the cylindrical seal portion 47α, the periphery of the mounting ring 46, and the periphery of the annular cylinder portion 32 are spaced radially inwardly from the inner wall of the sleeve portion 27 so as to define an annular passageway 48 which is adapted to communicate with the cylinder portion 28 above the piston 32. Fluid flow through this passageway is controlled by the seal lip portion 47b. Passageway 48 communicates with the exterior of the mechanism, i.e. with well bore fluid, through passageway means such as the illustrated space 49 between the lower edge of the sleeve portion 27 and the top of the enlarged sleeve portion 34. As will be appreciated, the upwardly diverging character of the seal lip 47b will serve to prevent the flow of fluid out of the cylinder portion 28 while allowing well bore fluid from the exterior of the apparatus to flow through the passage 48 into the cylinder portion 28.

With the check valve arrangement heretofore described, the apparatus may be lowered into a fluid filled well bore without any coupling fluid being initially contained within the cylinders 20 and 26. Upon being immersed in the well bore fluid, these cylinders will automatically fill in response to the pressure differentials existing across the seal lip portions 426 and 476. This check valve arrangement also insures that the cylinder cavities will remain constantly fully filled so that there will always exist an effective, pressure transmitting fluid coupling between the pistons 21 and 30.

In describing a preferred apparatus embodiment, several advantages of the invention have been demonstrated.

A foremost advantage of the invention resides in the manner in which the force transmitting mechanism causes the setting components of an apparatus to move relatively rapidly and with relatively low applied force when the

3,303,884 apparatus offers relatively low resistance to setting and the setting components of the apparatus are most freely movable. An especially significant facet of the invention involves the manner in which the force transmitting mechanism automatically causes apparatus setting components to under a change in rate of movement, accompanied by a change in rate of applied force, so that while apparatus components are least freely movable and offer the greatest resistance to setting, they are moved at a relatively low speed but with relatively great applied force.

Another significant aspect of the invention involves the manner in which the check valves associated with the two pistons of the force transmitting mechanism enables the apparatus to be lowered into a fluid filled well bore even though not containing coupling fluid. Once immersed in the fluid, with there being a sufficient difference in pressure between the well bore fluids and the cylinder interiors effective to open the check valves, well bore fluid will automatically flow into and fill the cylinders. This check valve arrangement will also insure that the cylinders will remain filled throughout the operation of the apparatus so that the pistons of the force transmitting mechanism will remain constantly in fluid coupled relationship.

An additional noteworthy aspect of the invention involves the manner in which the two piston of the force transmitting mechanism may be exposed to the well bore fluids but remain substantially pressure balanced.

It is also apparent that the force transmitting mechanism, while characterized by overall structural simplicity, will also be characterized by operational reliability.

While the invention has been described with reference to a preferred embodiment, it will be apparent that the utility of the force transmitting mechanism is not limited to the setting of the illustrated packer embodiment. It will also be apparent that the invention is not limited to the illustrated dimensional relationships of the various piston and cylinder components of the force transmitting mechanisms, to the illustrated piston, cylinder, configurations and seal to the use of a multi-stepped piston having two reactive areas, or to the use of the specifically illustrated check valves.

In describing the invention, various apparatus elements, normally multi-component in character, have been shown as unitary assemblies so as to avoid structural complexity which might obscure the invention.

Those skilled in the art and familiar with the disclosure of the invention may well recognize additions, deletions, substitutions and modifications which would be within the purview of the invention as defined in the appended claims.