US2737242A

US2737242A - Explosion resistant well packer

Info

Publication number: US2737242A
Application number: US305239A
Authority: US
Inventors: Reuben C Baker
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1952-08-19
Filing date: 1952-08-19
Publication date: 1956-03-06
Anticipated expiration: 1973-03-06

Description

March 6, 1956 R. c. BAKER EXPLOSION RESISTANT WELL PACKER Filed Aug. 19, 1952 REUBEN L. BAKER,

United States Patent 1 2,737,242 EXPLOSION RESISTANT WELL PAGKER Reuben C. Baker, Coalinga, Calif.,-assignor t Baker Oil 'Tools, 'Inc., Los Angeles, Calif., a corporation of Cali fornia Application August 19 1952, Serial No. 305,239 9 Claims. (Cl. 166123) T he present invention relates to subsurface Well equipment, and more particularly to well packers adapted to be set in packed-01f condition in well bores.

Well packers, such'as bridge plugs, areoftentimes set in a string of well casing to form a solid barrier therein. Following the-setting operation, the casing maybe perforated above the packer by an explosive device, which may consist of shooting bullets or a shaped charge through the casing. string. -At times,the detonation of the explosive tends to loosen the set packer in the welleasing and-may, in fact, completely release it from the well casing, the packer then being incapable of performing its function of providing a positive separating barrier within the casing.

Accordingly, an object of the present invention is to provideawell packer that is not releasable from the well casing when subjected to explosiveforces-thereabove.

Another object of the invention is to provide a well packer that utilizes forces incident'to explosions in the well casing to anchor itmore firmly in packed-off condition in the well casing.

This invention possesses many other advantages, and has other objects which may be made moreclearly apparent from a consideration of a form in which. it may be embodied. This form is shown in the drawings ac companying. and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but. it is to be understood that such detailed description is not to be .takenin a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a longitudinal section of a well packer embodying the invention, in combination with a portion of a setting tool, all disposed within a well casing;

Fig. 2 is an enlarged longitudinal section disclosing'the well packer anchored in packed-off condition in the well casing;

- .Fig. 3 is a cross-section taken along the line 3-3 on Fig. 2;

,Fig. 4 is a fragmentary longitudinal section through one of the latching or detent devices embodied in the well packer.

As illustrated in the drawing, and particularly- Figure 1.,

a well. packer A is lowered in a string of well casing B,

disposed in a well bore, by means of a setting tool C, a

portion only of which is disclosed. When the desired lo- As disclosed, the well packer A includes a generally tubular body 10 having a central passage 11 therethrough which is closed at its lower portion by a suitable-threaded plug 12. A guide and abutment member 13 is threaded .on the lower end of the body 10, supporting a set of lower segmental slips .14 provided with downward and out- .wardly inclined inner tapered surfaces 15 adapted-to .co-

operate with a companion. tapered surface 216' one lower expander 17 slidable with respect-to the body. The lower slipsiare'hel'd initially in retracted position by shear screws 2,737,242 Patented Mar. 6, 1956 ice 18' attaching them to the lower expander 17, .the1latter part, in turn, beinginitially secured to the bodyby' one or more shearscrews 19.

A packing sleeve 20, of natural orsyntheticrubber', or other suitable material, encompasses the .body,10, with its lower end engaging the upper end .of the lowerrexpander 17. The other end of the packing. sleeve engages an upper expander 21 that is also slidable relative .to .the body, being initially attached thereto by one orinor shear screws 22. This upper expander has an outer. surface 23 tapering upwardly and inwardly for coac'tion with companion tapered surfaces 24 in a plurality of upper segmental slips 25 whose upper ends bear against nie ower' end of a slidable rock ring or abutment 26 .initiauysecured to the upper end of the Packet body 10 by one or more shear pins or screws 27. The upper Slips are'held initially in retracted position by shear screws 28sccuring them to the upper expander 21. v v

The

shearscrews

27, 28 have a lesser combined shear value than the shear screws 22. The latter screws, in turn, have a lesser shear value than the combined shear value of the

screws

18, 19.

The lower expander 17 and lower. 'slips 14 are designed to anchor the well packer A against downward ,move ment in the well casing B, whereas the upper slips" 25. and upper expander 21 are designed to anchor the welllpacker againstupward movement in the well casing. After .the

slips

25, 14 and packing sleeve 20 ,have been expanded outwardly against the well c'asing',.in the manner described hereinbelow, they are prevented from releasing .by a oneway type of lock device, which operates between the upper lock ring or abutment 26 and the upperportion of the packer body 10. As disclosed, the upper peripheral portion of the packer body is formed with a plurality .ofcircumferential ratchet teeth 29 facing in adownward' direction. A split, inherently contractibleratchet lock ring or sleeve 30 is disposed within the" lock ring 26. This ring has a series of longitudinally spaced circumferential ratchet t'eeth31 facing in the opposite direction frornthe body ratchet teeth 29, but eng'ageable therewith to prevent downward movement of the body 10 with respect .to the split ring 30, while permitting the body to move upwardl-y with respect to this ring. The outer surface of the lock ring is provided with a plurality of upward and outwardly tapering annular cam surfaces 32 engaging companion surfaces 33 in the lock ring 30'. The lock ring .30 may expand laterally outward to a sutficient extent to allowv the body 10 of the packer to ratchet upwardly through the ring. However, downward movement of the .body .10 couples it to the long ring 30, and through the camsurfaces 32,. 33, effectively couples the body 10 totheuppcr abutment 26. V I

The setting tool and packer combination C.' A dis"- clos'ed is essentially of the type specifically described in the application of Reuben C. Baker and Martin .3. Con.- rad, serial No. 62,326, filed November 27, 1948 .for Pressure Operated Well Apparatus, now patent .No. 2,637,402. The setting tool C, itself, forms no part of the present invention, being shown in the present case as one form of device for appropriately anchoring the Well packer A inpacked-ofi condition in the well casing Eat the desired setting location.

The setting tool C includes a mandrel 40 threaded into a sub 41 threadedly secured to the upper portion. ofa-atension rod or mandrel 42 extending downwardly through the body passage 11, its lower end being threaded onto ta release stud 43, which is, in turn,.threadedl y secured with.- in the plug 12 closing the body passage. The releasestud 43 is formed with a weakened section 44; so that thest'ud will pull apart at that point when suflicie'nt tensions imextends through a hole 45 in the upper transverse bafiie portion 46 of a shield 47, the latter member having a skirt 48 depending from the baffle portion and received within a counterbore 49 in the upper abutment 26, the lower end of the skirt resting upon the abutment itself. The setting tool C further includes a setting sleeve 50 that engages a shoulder 51 on the upper portion of the shield 47 adjacent its baffie 46, the setting sleeve being centered with respect to the shield by snugly embracing a generally cylindrical centering boss 52 on the shield itself.

As described in the above referred to application, a force is exerted within a portion of the setting apparatus (not shown), which is imposed in a downward direction on the setting sleeve 50, and in an upward direction on the mandrel 40, a sub 41, tension rod 42, release stud 43, plug 12, body and guide 13. When the force reaches a predetermined value, the downward action of the setting sleeve 50 and shield 47 on the upper abutment 26 will shear the pins 27 attaching the abutment 26 to the upper portion of the body 10 and also the screws 28 securing the upper slips 25 to the upper expander 21. When this occurs, the setting sleeve 50, shield 47, upper abutment 26 and slips 25 move downwardly, the slips shifting along the upper expander 21 and radially outward into anchoring engagement with the well casing B.

After the upper slips 25 have been fully expanded outwardly, the setting sleeve 50, shield 47 and upper abutrneut 26 cannot move downwardly to any further extent. Accordingly, the force provided in the setting tool then tends tomove the mandrel 40, sub 41, tension rod 42, release stud 43, plug 12, body 10 and lower guide 13 in an upward direction. When this force is sufficient, it overcomes the shear strength of the screws 22 holding the upper expander 21 to the body 10, disrupting the latter, and moving the body upwardly within the upper expander 21 and also within the upper lock ring or abutment 26, as permitted by the ratchet lock 30. The lower expander 17 is thus moved toward the upper expander 21, fore-shortening the packing sleeve 20 and expanding it laterally outward into firm sealing engagement with the wall of the well casing B. As the force of the setting tool increases to a further extent, still tending to move the body 10 upwardly, it eventually overcomes the shear strength of the

screws

19, 18 holding the lower expander 17 to the body and the lower slips 14 to the lower expander, the body shifting in an upward direction to slide the lower slips along the lower expander and radially outward into firm anchoring engagement with the well casing.

The .force in the setting tool C continues to increase, which further urges all of the slips 14, and the packing 20 into firmer engagement with the well casing, until the force exerted is suflicient to disrupt the release stud 43 at its weakened section 44, which then automatically releases the setting tool C from the well packer A and enables the setting tool to be withdrawn from the well casing. The setting sleeve 50 merely rests upon the concussion shield 47; so that the latter does not interfere with elevation of lateral direction to a substantial extent.

the setting sleeve. Similarly, following disruption of the release stud 43, the tension rod 42 can move radialy through the hole 45 in the bafile portion 46 of the shield 47, the shield remaining in place around the upper portion of the body 10, and with its bafile portion 4'7 extending at least partially across the body passage 11.

' For the purpose of preventing the shield 47 from being inadvertently lifted upwardly upon withdrawal of the setting tool C from the packer A, a one-way type of ratchet lock arrangement is provided between the shield and the packer body. As disclosed, advantage is taken of the ratchet teeth 29 formed'on the body for the other lock device. Holding pawlsordetent elements 53, in the form 4, ence by the holding pawls 53 and screws 56 with the appropriate engagement of the lower terminus of the skirt 48 with the upper movable abutment 26 of the well packer.

As disclosed in Fig. 1, the holding pawls 53 are above thtupper end of the packer, but, upon downward movement of the shield 47, under the influence of the setting sleeve 50, and the subsequent upward movement of the body 10 within these parts, as the tension rod or mandrel 42 is moved upwardly, the ratchet teeth 29 on the body are brought into confronting relation with the holding pawls 53, the parts then occupying a position such as illustrated in Fig. 2, in which all of the holding pawls engage one of the circumferential ratchet teeth, preventing upward movement of the shield 47 with respect to the body 10, holding the shield in snug engagement with the lock ring or abutment 26. Of course, due to the one-way characteristics of the ratchet lock arrangement for the shield, the shield 47 can move freely downward over the body, and, conversely, the body 10 can move freely upwardly within the shield during the setting operation.

It is to be noted that the shield 47 rests upon the lock ring or abutment 26. Accordingly, any downwardforce imposed upon it will be transferred through the abutment 26 to the upper slips 25, tending to urge the latter downwardly with respect to the upper expander 21 and slightly radially outward into firmer engagement with the well casing. Any extraneous forces that may be imposed upon the anchored well packer fromabove will act in a downward direction on the shield 47 and will tend to anchor the packer more securely in the well casing. As an example, if it is desired toperforate the well casing B above the well packer A, which sometimes may occur within five or ten feet of the well packer, the detonation of the explosive charge produces shock waves that act in a downward direction. If the shield 47 were absent, these shock waves might enter the body passage 11 freely and also act upon the upper end of the body, tending to shift the body in a downward direction, disrupting the ratchet lock to free the body 10, the abutment and guide member 13 secured to the latter moving away from the lower slips 14, and allowing them to loosen with respect to the well casing. As a result of loosening of the lower slips it may be possible under some circumstances for the entire well packer or bridge plug to slide downwardly within the casing B, or. for that matter, to become completely released therefrom. However, in view of the shield 47 provided at the upper portion of the well packer A, and particularly the transverse bafile 46 extending across its upper end, which battle, it is to be noted, has an upward and inwardly tapering surface60, the shock waves incident to an explosive force engage the bafiie 46 and are diverted thereby in a The restricted opening through the bafile may allow some of the force accompanying the shock waves to be imposed in a downward direction from the body 10, but the extent of this force is much less than in the absence of the baflle. In addition, the force of the shock wave or waves acting in a downward direction upon the shield 47 acts through the lock ring or abutment 26 and the upper slips 25 to anchor the well packer more firmly in the well casing, in the manner described above.

It is, accordingly, apparent that a well packer apparatus has been provided which is not releasable from the well casing when subjected to forces incident to an explosion immediately above the well packer. As a matter of fact, such explosive forces are utilized to more firmly anchor the packer in the well casing.

The inventor claims:

1. In well apparatus: a body having normally initially retracted means thereon adapted to be expanded laterally outward; an abutment slidable relatively downward along said body and engaging said normally initially retracted means; a shield engaging said abutment and'movable over said body, and relatively downward along-said body-to effeet expansion of said normally initially retracted means laterally outward; said shield including a bafiie portion disposed above the upper end of said body and extending laterally inward across said body; one-way holding means releasably interconnecting said shield and body to permit relative downward movement of said shield along said body but prevent relative upward movement of said shield along said body; and one-way holding means releasably interconnecting said abutment and body to permit relative downward movement of said abutment along said body but prevent relative upward movement of said abutment along said body.

2. In well apparatus: a body having normally initially retracted means thereon adapted to be expanded laterally outward; an abutment slidable relatively downward along said body and engaging said normally initially retracted means; a shield engaging said abutment and movable over said body and relatively downward along said body to effect expansion of said normally initially retracted means laterally outward; said shield including a bafile portion disposed above the upper end of said body and extending laterally inward across said body; ratchet teeth on said body; locking means on said abutment engageable with said teeth to prevent relative upward movement of said abutment along said body but permit relative downward movement of said abutment along said body; and locking means on said shield engageable with said teeth to prevent relative upward movement of said shield along said body but permit relative downward movement of said shield along said body.

3. In well apparatus: a body having normally initially retracted means thereon adapted to be expanded laterally outward; an abutment slidable relatively downward along said body and engaging said normally initially retracted means, said abutment having an upper counterbore; a shield disposed within said counterbore and engaging said abutment and movable over said body and relatively downward along said body to efiect expansion of said'normally initially retracted means laterally outward; said shield including a baflle portion disposed above the upper end of said body and extending laterally inward across said body; ratchet teeth on said body; locking means on said abutment engageable with said teeth to prevent relative upward movement of said abutment along said body but permit relative downward movement of said abutment along said body; and locking means on said shield engageable with said teeth to prevent relative upward movement of said shield along said body but permit relative downward movement of said shield along said body.

4. In well apparatus: a body having normally initially retracted means thereon adapted to be expanded laterally outward; an abutment slidable relatively downward along said body and engaging said normally initially retracted means; a shield engaging said abutment and movable over said body and relatively downward along said body to effect expansion of said normally initially retracted means laterally outward; said shield including a baffle portion disposed above the upper end of said body and extending laterally inward across said body; ratchet teeth on said body; locking means on said abutment engageable with said teeth to prevent relative upward movement of said abutment along said body but permit relative downward movement of said abutment along said body; and one or more leaf springs on said shield engageable with said teeth to prevent relative upward movement of said shield along said body but permit relative downward movement of said shield along said body.

5. In well apparatus: a body; an expander on said body; normally initially retracted slips coacting with said expander to be expanded laterally outward of said body; means slidable relatively downward along the exterior of said body and engaging said slips for shifting said slips along said expander and laterally outward; said slidable means including a baflie portion disposed above the uppermost end of said body and extending laterally inward across the uppermost end of said body to a substantial extent toward the axis of said body to reduce the downward force of an explosion above the well apparatus on said body; and one-way holding means releasably interconnecting said slidable means and body to permit relative downward movement of said slidable means along said body but prevent relative upward movement of said slidable means along said body.

6. In well apparatus: a body; an expander on said body; normally initially retracted slips coacting with said expander to be expanded laterally outward of said body; means slidable relatively downward along the exterior of said body and engaging said slips for shifting said slips along said expander and laterally outward; said slidable means including a baflie portion disposed above the uppermost end of said body and extending laterally inward across the uppermost end of said body to a substantial extent toward the axis of said body to reduce the downward force of an explosion above the well apparatus on said body, said baflie portion having a centrally disposed hole therethrough; and one-way holding means releasably interconnecting said slidable means and body to permit relative downward movement of said slidable means along said body but prevent relative upward movement of said slidable means along said body.

7. In well apparatus: a body; an expander on said body; normally initially retracted slips coacting with said expander to be expanded laterally outward; an abutment slidable relatively downward along the exterior ofsaid body and engaging said slips; a shield engaging said abutment and movable over said body and relatively downward along the exterior of said body to efiect expansion of said slips laterally outward; said shield including a batfle portion disposed above the upper end of said body and extending laterally inward across said body; and one-way holding means releasably interconnecting said shield and body to permit relative downward movement of said shield along said body. but prevent relative upward movement of said shield along said body.

8. In well apparatus: a body; an expander on said body; normally initially retracted slips coacting with said expander to be expanded laterally outward of said body; means slidable relatively downward along the exterior of said body and engaging said slips for shifting said slips along said expander and laterally outward; said slidable means'including a bafiie portion disposed above the uppermost end of said body and extending laterally inward across the uppermost end of said body to a substantial extent toward the axis of said body to reduce the downward force of an explosion above the well apparatus on said body, said baflle portion tapering in an upward and inward direction; and one-way holding means releasably interconnecting said slidable means and body to permit relative downward movement of said slidable means along said body but prevent relative upward movement of said slidable means along said body.

9. In well apparatus: a body; an expander on said body; normally initially retracted slips coacting with said expander to be expanded laterally outward of said body; means slidable relatively downward along the exterior of said body and engaging said slips for shifting said slips along said expander and laterally outward; said slidable means including a bafiie portion disposed above the uppermost end of said body and extending laterally inward across the uppermost end of said body to a substantial extent toward the axis of said body to reduce the downward force of an explosion above the well apparatus on said body.

References Cited in the file of this patent UNITED STATES PATENTS 2,345,872 Hart Apr. 4, 1944 2,345,873 Hart Apr. 4, 1944 2,566,323 Forsyth et al Sept. 4, 1951