US2368409A - Well packer - Google Patents

Description

.are retained initially on the packer body .in retracted positions to permit lowering of the pack- Patented Jan. 30, 1945 11%, 11,

Clarence E. Burt, Los Angeles, Calif; assignor to I Baker Oil Tools, 1110., Vernon, Calif., a-ccrporation of California Application November 14, 1 94 1 Serial No. 119:1147

; '2 Claims. (01. its-I2?) This invention relates to well packers which are utilized in packing off, cementing, producing, and other analogous operations in oil and gas wells.

Well packers adapted to be run in casings are usually provided with packing members for effecting a seal between the packer body and the casing wall, and also withslips for securing the packer to the casing. These slips and packings er device to the desired point in the well casing before the slips and packing are set. In some circumstances, conditions of the hole or casing cause premature setting of these casing engaging members, as for example, upon their encountering foreign substances within the casing which tend to force them to a setting position before the desired point in the casing or operatingjco'ndition is reached.

It is therefore an object of the present invention to materially lessen, if not eliminate alto gether, the hazards of premature setting of a well packer in a casing.

Where segmental slips are employed in a well packer, it sometimes happens that they do not all move uniformly from their retracted positions into anchoring engagement with the wall of the casing. Instead of remaining in alignment, the slips may occupy different longitudinal positions along the wall of the casing, tending to place the well packer in an ofi-center position therewithin and imposing excessive strains upon it. i

It is a further object of the present invention to overcome this difficulty by maintaining the segmental slips or any set of packer anchoring members in alignment, and thus ensure their engagement with the casing while they are'substantially in the same transverse plane.

Some forms of well packers, such 'as the packers known as cement retailers, are removed from the casing by the rotary method of drilling after performing their particular iu'n'ctions in the well casing. Parts of the retainers have heretofore been difli'cult to remove by drilling, due to their tendency to turn with the drill bit, rather than remain stationary and enable the bit to p'ulverize them for easy conveyance in the drilling fluid to the surface of the hole.

Accordingly, it is another object of the invention to prevent rotating of well packer parts which are later to be removed fromfthe casing by a rotary drinin'ger similar operation.

This invention has other objects that willbe- 'coine apparent from "a -cons iderati'on or the emb'odim'ent shown the drawing accompanying and for-mingpart of the present specification. This form will now be described-in detail to illustrate the generalprinciples of the "invention, but it is to be understood'that such detailed description is not to be taken in a limited sense, since the scope of the invention is best *defined by the appended claims. 10

neierrmg to the drawing: Figure l is a longitudinal 'view,'partly in section and partly in elevation, of a wellypacker with its parts in retractedp'osition;

"Figure -2 is a View similar to Figure 1, with the ell packer disclosed asset in packed on condi-\ tion within -a well casing; and i Figure 3 is a cross-section taken along the line 33 in Figure 1.

The well packer A may be lowered to the desired setting point in a well casing B on the end of a tubular string C, which 'is suitably coupled "to the upper end thereof. The packer "includes a main body 10 carrying a's'et of upper annular segmental tapered slips H adapted to be moved 'into engagement with'the casing by an upper expander cone l2 initially retained in retracted position by one or more shear screws 13 attaching it to the main body. The upper slips "H "are similarly retained in retracted "or ineffective position by shear screws l4 securing In addition, the upper ends of these slips ll engage the lower surface of'an abutment ring l5 threaded on thexmain 'body, with "the slips held against the external cylindrical surface of the body by a split ret'ainer ring 16 positionedwithin a circumferential fgrodve H formed jointly in the exteriors of the slips,and bearing against the'bottom or the groove ll to hold the slips ll snugly agains the body 0.

-A lower set of annular segmental tapered 'slips [8 is initially held in retracted position by attachingit' to answer expander cone l9 through the medium of shear screws 20, "this latter cone being initially held' 'in ineffectivefposition by suitable frangible connections in the 'form of shear screws 2| threaded into the body. The lower 'ends'of these slips also engage an 'abutment consisting of a, flange .22 at the lower end *of the body anda valve housing 23 threaded on this fiange. Upward movement of the slips I8 along the body l0 when/in retracted position'is p'i'evented by pins (24 fi'xed'to the body fand'ex- --tending*outward1y intoholes 25 p'rbvided in the sun's; I-his pm a-m1 hole arrangement 'rorm's a I ll radially slidable connection between the body I and slips I8, which will prevent longitudinal movement of the slips along the body, but which still allows the slips to be shifted radially of the body by the tapered expander I2.

A packing sleeve 26 of synthetic or natural rubber is positioned on the body between and suitably secured to the ends of the expander cones I2, I9. This sleeve is initially retained in retracted position free from contact with the casing wall, but it is capable of being expanded, into engagement therewith.

The valve housing 23 carries a tripping ball' seat 21 therewith initially held in position bya shear screw 28. This seat has an upstandingproper operation of the'packer device permits the ball 30 to engage its cooperable valve seat 3| whenever reverse flow of fluids through body tends to occur. I

The packer A is run into the casing B to the desired point and circulation established therethrough to remove any undesired foreign matter. Thereafter, a tripping ball 32 is lowered or pumped down through the tubular string into seating engagement with the tripping ball seat '21, which permits the pressure of the fluid within the packer body to be increased for passage through ports 33 opening through the body into the interior of the packing. The fluid under pressure moves the upper cone I2 upwardly along the body to disrupt the shear screws I3, I4 and expand the upper slips II outwardly into gripping engagement withthe casing.

the

might tend to shear the screws holding them to the cone (9 and force themupwardly therealong into engagement with the casing. Should debris or foreign matter tend to move the slips I8 upwardly, such action would be prevented by the body pins 24 extending into the radial holes 25 through the slips. This pin and hole combination precludes upward movement of the lower slips along the body, without preventing their radial'outward movement into engagement with the casing upon the taking of an upward strain on the body, as described above. In a similar manner, engagement of the upper slips II with the abutment ring I5 while they'are in retracted position also guards them against premature tripping in the event of elevation of the well packer in the casing.

After the tripping ball 32 has engaged its seat It is to be noted that the abutment ring I5 prevents upward movement of the slips I I, thus causing their radial expansion upon longitudinal movement of the cone I2 along the packer body III. After the upper slips have been set, the pressure of the fluid is increased to shear the pin 28 holding the tripping ball seat 21 in the valve housing 23, whereupon this seat together with its upstandingarm 29 is pumped from the well packer, so as to allow the closing of the back pressure valve 30, 3I whenever reverse flow of fluids tends to occur. The taking of an upwardly directed strain on the tubular string C and main body In then compresses the packing 26 between the casing wall and exterior surface of the body, while the continuation of this strain shears the screws 2I and 20 holding the cone to the body and the slips to the cone, causing the lower slips I8 to move along the coneI9 and radially into engagement with the casing B. The well packer is now in set position for the performance of a cementing, production or other operation, or to function as a bridge plug, as explained in United States Patent No. 2,121,051, to which attention is invited for further structural and operational details of this type of tool.

In the former designs of well packers, especially of the type above described, debris and other foreign matter in the well casing has sometimes caused premature tripping of the lower slips I8 while the tool was being run in the well bore. The mounting of the lower slips I8 so that they do not extend laterally beyond the confines of the valve housing 23, and their engagement while in retracted position with this housing and the body flange 22, prevents their being contacted detrimentally by foreign matter which gate the packing 26, for the purpose of shearing the upper screws I3, I4 to move the upper slips I I into engagement with the casing, the pressure within the tubular string C and tool may be bled off, allowing the packing 26 to return or contract to its initial position and move the cone I2' downwardly along the body I0. Ordinarily, the upper segmental slips II drop downwardly with the cone I2 and maintain their aligned position in engagement with the casing so as to keep the tool body centered therewithin. 'At times, however, one of the slips may drop ahead of the others, producing their disalignment and causing lateral strains of large magnitude to be imposed on the packer body It When the subsequent upward pull is taken on the tubular string C and body to pack oif the tool and set the lower slips I8.

-The split slip retainer ring I6 precludes the above-mentioned disalignment from occurring. Not only does this element engage the bottom of the composite circumferential groove I? to hold the slips II against the body Ill, but it also prevents the slips from disaligning in the event that the cone I2 is pulled back down along the body by the packing member 26 upon relieving of the fluid pressure within the tool. It is readily observed from the drawings that the split ring it bridges the gaps IIa between the segments and couples them together for conjoint movement in a longitudinal direction.

This ring I5 preferably engages the bottom of the circumferential groove I1 and exerts a slight contracting force against the slips II, holding them in engagement with the body. However, this force is insuificient to prevent radial expansion of the slips against the casing, nor is it great enough to pull the slips back inwardly upon retrograde movement of the cone I2. The retainer ring Ifi is similar to an automotive piston ring, and may be made of cast iron or mild steel.

Difficulties have sometimes been encountered in drilling up well packers after they have performed their function in the well bore, due to the rotation of the body in the expander cones under the influence of the drill bit. As the bit is rotated by the drilling string, the body merely revolves with it within the cones, which are held stationary by the slips, so that the necessary relative motion between the drilling bit and body does not occur to efiect its removal.

The present invention overcomes this difliculty by keying the bottom cone I9 to the body In in such manner as to prevent relative rotation therebetween while permitting relative longitudinal movement to occur. The specific'key disg 2,368,409 closed in the drawing consists simply of 'a keyway screw 36 threaded within the hole and engaging the ball 34.

It is readily apparent from this construction that the body I cannot rotate with respect to the cone I9, enabling the rotary drill bit to disintegrate it together with the other packer parts. However, the body l0 may be pulled upwardly within the cone l9 without restraint from the ball lock and keyway combination.

A well packer has thus been provided which overcomes certain disadvantages of former designs. Premature tripping of. the slips is prevented, the slips are maintained in alignment, and the packer parts are so coordinated as to facilitate their drilling up whenever such action becomes essential or desirable.

I claim:

1. A well packer, which includes a body having a lower abutment secured rigidly to it, normally retracted tapered slips arranged around said body, a downwardly converging tapered expander slidable along said body within said slips for moving said slips into engagement with the wall of said well casing to anchor said well packer therein against downward movemenafrangible means securing said slips to said expander in retracted position within the confines of said 7 lower abutment and with their lower ends en gaging said lower abutment, means on said slips and body forming a radially slidable non-shearing connection while said slips are in retracted position to prevent upward longitudinal movement of said slips along said expander prior to disruption of said frangible means, said radially slidable connection allowing said slips to be shifted radially of said expander into engagement with said casing wall upon disruption of said frangible means.

2. A well packer, which includes a body having a lower abutment secured rigidly to it, normally retracted tapered slips having radial holes therein and arranged around said body, a downwardly converging tapered expander slidable along said 'body within said slips formoving said slips into engagement with the wall of a well casing to anchor said well packer therein against downward movement, frangible means securing said slips to said expander in retracted position within the confines of said lower abutment and with theirlower ends engaging said lower abutment, non-shearing pins secured to said body and slidably fitting in said holes while said slips are in retracted position to preventupward longitudinal movement of said slips along said expander prior to disruption of said frangible means, said pin and hole connection allowing said slips to be shifted radially of said expander into engagement with said casing wall upon disruption of said frangible means.

CLARENCE E. BURT.

y Patent No. 2,568, L09. January 0, 1914.5.

CERTI FI GATE OF C ORBEC TI ON CLARENCE E. BURT.

of the above numbered patent requiring correction asfollows Page 1, first column, line h2, for "retailers" read --retainers--; page 2, first coluinn, line lL for "therewith" read --therewithin--; and that the said Letters Leslie Frazer

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