US2338370A - Cement retainer - Google Patents

Description

M. C.. WILSON CEMENT RETAINER Jan. 4, 1944,

Filed July 29, 1940 2 Sheets-Sheet l INVENTOR. 5 am 6.09am

2 Sheets-Sheet 2 M. c. wlLsoN CEMENT RETAINER Filed July 29, 1940y Jan. 4, '1944.

NVENTOK v BY im (5. @ank ATTORNEY Patented Jan. 4, 1944I UNITED STATES PATENT OFFICE;-

CEMENT RETAINER Milo C. Wilson, Corpus Christl, Tex.

Application July 29, 1940, Serial No. 348,146

(Cl. 16B-12) 2 Claims.

troduced into the well bore and pressure applied to the formation of the well bore. 1

Cement retainers of this type are usually lowered into the well bore on a string of pipe anchored in position and the pressure then applied thru the operating or setting pipe. It is the function of the cement retainer to become firmly lodged in the pipe so 'as to withstand any upward thrust caused by the pressure applied thru the operating pipe. In other words, the cement retainer merely anchors the lower end of the pipe in the well so as to facilitate the application of pressure to the formation, regardless of whether the cement is discharged from the lower end of the pipe or casing or thru perforations in the pipe or casing.

It is one of the objects of the present invention to provide a cement retainer which can be lowered into the well bore and firmly anchored by a partial rotation yof the operating pipe and an upward pull thereon which merely acts to set the slips and has no setting action so far as a packing or seal is concerned.

Another object of the invention is to provide a combination of an anchoring device and a pressure operated packer wherein the thrust on the packer is exerted against the slips, and not against the wedging means which initially sets the slips s'o that the slips do not become locked in position due to the cement pressure.

Another object of the invention is to provide a cement retainer which is not self actuating'and which can be readily removed rfrom the well bore. i

vide a cement retainer which is not self actuating and which can be readily knocked loose by a downward movement of the operating pipe'.

A still further object of the invention is to `provide a cement retainer which can be an chored by an initial pull on the operating pipe to set the slips and wherein the slips will be urged into gripping action by the pressure applied to the tool from below so as to avoid placcompanying drawings in which:

Fig. 1 is a side elevation of the cementing tool; Fig. 2 is' a vertical section ot the tool of Fig. 1

Still another object of the invention is to protaken on a section line perpendicular to the sheet i of the drawings and illustrating the tool in contracted position as it will be lowered into the well bore.` V

- Fig. 3 is a. section similar to Fig. 2 but showing the cement retainer as having been' anchored or set in position.

Fig. 4 is a side elevation of the J-latch connecthreads 4 as seenin Figs. 2 and 3. The threads 4 are preferably a left hand thread so that the pipe 2 may be backed out of or unscrewed from the tool by rotation in a clockwise direction. A

shear pin 5 normally prevents such unscrewing 'and is adapted to lbe sheared only when a predetermined torque is exerted on the pipe 2 while the tool) is anchored.- Under most circumstances this pin l will be of such strength thatV to set the slips or 'jawsP il which have cox'nple-y mentary inclined faces riding `on the face Il 'of v the wedge. Each slip i3 has a shoulder I5 adiacent its lower end and a heel i8 extending inwardly from the shoulder i5 and arrangedto engage the lower wedge I2. The slips are slidably mounted in openings in a housing 20 l surrounding the mandrel i0.

Below the wedgesrthe mandrel i0 is reduced in external diameter to provide a pipe i1 which 'is open at its lower end.

- Positioned around the mandrel i0 is a sleeve or housing 2i! which is normally connected to the movement between the mandrel -and yhousing extending but when the mandrel is rotated in a counter- .to the housing to raise the upwardly tapered wedges I2 to engage and extend the slips I3 into engagement with the well casing. Lowering the mandrel will tend to retract the wedges from the slips andpermit them to be loosened from the casing. In order to equalize the pressure of liquidin the well and in the slip chamber 25' a port 2B is provided in the housing underneath the wedges I2. This port 23 also allows the washing out -of any sediment which may work into the tool. The slips I3 are retained against displacement from the housing bythe hold-down plates 21 secured to the housing and the heels IB on the slips.v

In order to create a drag on the housing so as to facilitate the setting and releasing of the slips I3 the dragbars 3U are provided. Three of these bars are seen in Fig.- '1 and they'are disposed, in the slots 3l in the housing and normally urged outward by the springs 32. The tips 33 of these bars are coniined by the stop plates 34 which are ailixed to the housing. These bars normally project beyond the diameter of the housing as seen in Figs. 2 and 7, to engage the pipe 35 in the well bore in which the tool is to be set. In this manner there is a tendency for -the housing 20 to remain stationary except when it is caused to move by movement of the mandrel I0,

With the parts in the position shown in Figs. 4 and 'l with the latch preventing relative movement of the mandrel in the housing, the assembly will be lowered into the well bore. A partial rotation of the operating pipe 2 and the mandrel I0 release the J-latch so that the mandrel may be pulled upwardly relative to the housing. The

drag bars 30 tend to hold the 'housing stationary and this resistance is sufllcient to permit the mandrel moving upwardly relative to the housj ing to extend the slips into gripping engagement with the well casing.

i packer support 42 is threaded'into the lower end and forms a part of the housing 20 as seen in Figs. 2 and 3 and this support may carrya plurality of iiuid pressure operated packings' 4I each of which is in the form of a downwardly facing lpacking cup 40 which is retained by the cap 43. In this manner a lipf type of packing is provided by the recess 44 under the packing so that pressure vfrom below will expand the packing and cause it to seal with theplpe 35. The packings 45 carried by the inside of the housing 20 form a seal between the mandrel and the housing. The packer support 42 has a passage 41 therethrough which is a continuation of the passage II .in the mandrel. A retainer nipple 48Min the couplings 49 tend to hold the lower packer in place.

Particular attention-is directed to the fact that the slip jaws I3 are freely floating in the openings 50 in the housing 20 as seen in Figs. 2, 3 and 5,

and also to the fact thatfthe'shoulder 5I on the housing is 'arranged to engage the shoulder I5 on the lower portion of the slip. This construction is provided so that when the tool is set as shown in Fig. 3, a pump pressure applied thru the operating pipe 2 and the passages II and 41 to force liquid or cement into the well bore, 'is also applied to the packers 4I, tending to move these packers upwardly.

Inasmuch as the packers are mounted on the housing 20 it seems obvious that there would 'ange 55 to rap the shoulder 56 which will assist in maintaining them in set position but attention is called to the fact that this same pressure does not tend to drive the wedges ,l 2 against `the slips because the movement of the housing 20 can be independent of the mandrel I0 after the J-latch has been released. This feature is belleved to be of importance because of the fact that in other types of cement retainers the pres sure applied thru the retainer to the liquid is exerted on the retainer, tending to drivey the wedges more firmly against the slips and inasmuch as tremendous pressures can in this manner be attained, it seems obvious that the wedges would be driven against the slip with such atremendous pressure that in some instances it has been found that a release could Inot be obtained. In the present device, however, this pressure is not exerted on the wedges but is exerted on the housing and the slips. The wedges are thus forced against the slips with only the pressure exerted by a pull on the operating pipe so that it seems clear that the slips can be released by merely lowering on the operating pipe with the assur-A ance that the wedges will move out from under the slips and will not have been permanently wedged into position by the pumped pressure thru the tool.

To insure that the slips will be released from their gripping engagement with the pipe 35 when the wedges I2 are moved downwardly a ilange 55 has been provided on the upper end of the mandrel and projects outwardly so that it is adapted to engage the shoulder 5B on the top of the housing. When the mandrel is pulled upwardly this ilange 'will move away from the housing and assume the position shown in Fig. 3. When, however, the tool is to be released, the lowering of the mandrel will lower the ilange 55 and should the jaws I3 vnot release, additional downward movement of the operating pipe 2 will cause the readily dislodge the slips by knocking the housing downwardly.

As pointed out above if the tool should become lodged in the pipe 35er stuck with cement, the

threads 4 can be released andthe operating pipe 2 removed, due to the fact that the threads 4 are a left hand thread.

An additional left hand thread 51 is used to connect the packer support 42 with the lower end of the housing and this thread is also a left hand thread so that if the lower end of the tool includ- 'ing the packer support 42 should become lodged in the well, the remainder of the tool, including the housing 20 above the packer support 42 could be readily unscrewed and removed due to this left hand thread 51.

When the cementing operation is completed it isl desirable to remove the cement from the tool before it sets., To do this the circulation may be reversed and the ilow would be down inside of the pipe-35 and against the packings 4I. This will depress the rubber and allow the pressure to iiow up thru the tool. The cement can in this man ner be washed out and the tool ready for removal.

Broadly the invention contemplates a cement tool may be readily released should the occasio i require.

What is claimed is:

1. A cement; retainer for wells including an operating pipe, a mandrel thereon, a housing about said mandrel, an inverted- J-latch connecting said housing and mandrel, slips carried by said housing and a slip wedge on said mandrel so that upon release of said latch relative movement of the mandrel and housing sets said slips, a packer carried by said housing and having a lip thereon facing downwardly to be expanded by fluid pressure from below, a continuous open passage thru said mandrel and housing, drag means on said housing tending to resist movement of the housing in a pipe in the Well, and means on said mandrel to contact said housing on downward movement of said mandrel so as to knock said housing and slips loose from the pipe when said mandrel and the slip wedges are moved downwardly.

2. A` cementing tool comprising an operating pipe, an open hollow mandrel thereon, a housing about said mandrel, a latch means connecting said housing and mandrel and operable to permit movement of said mandrel relative to said housing, a set oi' upwardly facing tapered faces on said mandrel, a set of slips carried by said housing, tapered faces on said slips to cooperate with said mandrel faces whereby to move said slips into anchoring position by upward movement of said mandrel relative to said housing and slips to anchor the tool in the well, packer means on said housing to effect a seal therearound upon application of pressure through said mandrel, and means on said mandrel to engage said housing upon relative downward movement so as to knock said housing and slips loose from anchored position.

MELO C. WILSON.

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