US2672934A

US2672934A - Method and apparatus for releasing packers

Info

Publication number: US2672934A
Application number: US120201A
Authority: US
Inventors: Keith H Miner
Original assignee: Lane Wells Co
Current assignee: Lane Wells Co
Priority date: 1949-10-07
Filing date: 1949-10-07
Publication date: 1954-03-23
Anticipated expiration: 1971-03-23

Description

March 23, 1954 I MINER 2,672,934

METHOD AND APPARATUS FOR RELEASING PACKERS Filed 001;. 7, 1949 2 Sheets-Sheet 1 I4 IO lo .5 G E i I5 I I5 I 2 I 6 i l g 7 7 I 16 16 I 19 i :9

I7 I I8 56 35 Q" \7 8 IN V EN TOR.

March-'23, 1954 M|NER 2,672,934

METHOD AND APPARATUS FOR RELEASING PACKERS Filed Oct. 7, 1949 2 Shee'ts-Sheet 2 6 ill! llll L IN V EN TOR.

KEITH H. MIN

A7770EA/EV Patented Mar. 23, 1954 METHOD AND APPARATUS FOR RELEASING PACKERS Keith H. Miner, Caracas, Venezuela, assignor, by mesne assignments, to Lane-Wells Company, Los Angeles, Calif., a corporation of Delaware Application October 7, 1949, Serial No. 120,201

11 Claims. 1

This invention relates to the use of packers in wells, especially oil and gas wells. More particularly it has to do with the freeing of packers which have become wedged or stuck in place-in well boreholes or casings by the accumulation of sand or hardened mixtures of sand and drilling mud above the packer, a condition which is generally referred to. as being stuck or sanded-in. This condition is frequently encountered when packers have been in place in wells for a long time or are setin wells to. isolate two or more producing zones. for dual or multiple completion and sand has entered from the upper producing zones and settled on top of the packers.

One object of the invention is, therefore, to devise a simple method and. apparatus for dislod ing and displacing sand and other material which settles and accumulates upon a packer and prevents it from being. released.

Another object is to provide an improvement in well packers. which will facilitate their removal from well. boreholes and casingsunder sandedin conditions.

This invention, broadly stated,.involves the provision of ports or passageways which are normally sealed by frangible closures or disks and located for discharging a flushing fluid beneath any sand and debris which may have accumulated on top of the packer sufficient to prevent its release. When the packer becomes sanded-in by such settlings, the frangible closures may be ruptured by suitable means to permit flushing fluid to be forced out of the ports under pressure 'to' dislodge the settled sand or otherbinding debris. For convenience and eificiency the force of an explosive is preferably utilized to rupture the frangible closures. Besides rupturing the closures, the shock or vibration and fluid jetting action induced by the explosive also usually contributes materially to the loosening of the sand so that it is more readily displaced when flushing medium is subsequently forced through the ports. Bypreference the explosive force is applied from within the packer mandrel and thus it also tends to loosen the packer from its gripping engagement with the casing of the well. In practice, the explosive is lowered within the pipe string, towhich the packer is attached, and into the vicinity of or adjacent to the frangible closures in the packer head and in order to confine the force of the explosive to that area within the packer head, it is advantageous to block off the passage leading downward, from thepacker head through the packer mandrel to the pipe string therebelow.

1nthe drawings which illustrate a preferred 2 embodiment of the invention and manner of its use and in which like reference characters designate the same or similar parts throughoutthe several views:

Figure l is a vertical sectional view through the casing of a. well showing a well packer, modi fied in accordance with the present invention, as

it appears upon being lowered into the well prior to being set, the packer being shown mostly in elevation but partly in section;

Figure 2 is a vertical sectional view similar to Figure 1 but showing the packer as it appears when. set in the well and stuck in place by an accumulation of sand in the annulus above the packer, this figure being illustrative of steps of the method of releasing the packer;

Figure 3 is an enlarged vertical sectional view of a fragmentary portion of the upper end of the packer in the condition shown in Figure 2; and

Figure 4 is a similar, enlarged, vertical sectional view of a fragmentaryportion' of the lower end of the packer mandrel of Figure 2.

In Figure l, a packer, attached to the lower stand 5 of a pipe string, is illustrated as it appears while being lowered within well casing 6 preparatory to being set. The packer which is of the hook wall, by-pass circulation type, is conventional for the most part and may be constructed, although not necessarily so, in accordance with the patent to Renouf 2,005,955. As herein illustrated, the packer comprises a central mandrel 1 attached to the lower end of a suspending pipe string 5 by means of a top collar or packer head member 8. Carried slidably on mandrel I is. a slip cone member 9, supporting a plurality of packing rings It on its upper part and containing conventional slips ll dovetailed in downwardly convergent grooves onthe lowerv part of. member 9. Slips I I are provided with slip reins l2con'- necting them with a slip rein ring l3 carried on the cage sleeve of a conventional cage spring assembly of, the dowel and'J-slot typeandwh'ich is provided with outwardly bowed friction springs adapted to make frictional engagement with the surrounding casing to assist. in setting the packer. At the lower end of mandrel 'I is lower collar or connection I6 for attaching-a length of tail pipe or tubing 11. By preference and as shown, tail pipe H is provided with a section of reduced internal diameter forming an upwardly facing internal shoulder. 18 for the" purpose to. be described hereinafter. Tail" pipe I1 is-secured' to the lower end of mandrell'by-means-of a bottom sub l6 and coupling l9;

Telescopically slidably supported at the: top

of the slip cone member 9 is a packer sleeve 21 around which the annular packing elements H! are supported. Threaded to the top end of the packer sleeve 21 is an annular valve seat member l4 having a valve seat 20 which is adapted to be engaged by valve head 2| which is in turn carried at the lower end of the packer head 8, when the pipe string 5 and mandrel I are lowered relative to the slip cone member 9 in setting the packer. The annular, fluid by-pass passage 22 formed between the outside of the mandrel I and the inside surface of the packer sleeve 21 and the slip cone member 9 may thus be closed off.

The packer head 8, is provided with a plurality of ducts or ports 23 extending from the interior to the exterior thereof at a level slightly above the valve head member 2| and directed divergingly downward toward the top area of the valve seat member l4. For convenience of illustration, four such ports are shown in the drawings, although any other suitable number of ports may be employed. Each of the ports 23 is counterbored from the exterior to provide an annular shoulder 24, as best shown in Figure 3, against which is seated a closure element 25 which may take the form of a frangible disk of material which will shatter under a predetermined pressure impact or shock, as for example that caused by an explosive. The frangible closures or disks 25 may be of brittle metal such as cast iron, or glass or plastic material. A suitable retainer such as an externally threaded annular memher or ring 26 threaded into each counterbore,

serves to hold each frangible disk 25 securely in fluid tight engagement with its seat.

The setting of packers of the type shown in Figures 1 and 2 is well known and therefore only a brief description will be given herein. When the packer is at the desired depth in the well, where it appears as shown in Figure 1, pipe string 5 is turned rotationally in a lefthand direction, through an angle sufficiently to release the dowel on mandrel I from the horizontal to the longitudinal portion of the J-slot in the cage sleeve, whereupon mandrel E, top collar 8 and pipe string 5 are then free to be lowered while cage l4 remains stationary within the casing by reason of the frictional engagement of springs |5 upon the inside surface of well casing 6. As cone member 9 descends by gravity with the lowering of pipe 5 and mandrel l, slips move up in their slots relative to the slip cone and are forced outwardly thereby into gripping engagement with the surrounding well casing S. Valve 2| on top collar 8 next moves down into engagement with valve seat 2D and the weight of the pipe string applied through the packing elements I!) to the slip cone and slips telescopes the packer sleeve 21 into the slip cone member 9 compressing packing rings It longitudinally until they expand laterally into engagement with the casing 6. The packer is then set, as shown in Figure 2. An accumulation of sand or other hardened or dense settlings is shown at 39, in the annulus upon the packer head 8 and valve seat member 22 sufi'icient to wedge the packer in place by preventing the said packer head 8 and mandrel 1 from being raised to open valve 20, 2| and to prevent valve seat member 22 to raise relative to the slip cone 9 sufficiently to release the packing elements lll and slips II from gripping engagement with the inside of easing 6.

Release of the packer which has become stuck or sanded-in inthe beforedescribed manner is effected in accordance with the present invention by rupturing the frangible closures 25 in ports 23 so that flushing fluid is thereby jetted through, and can be discharged, through ports 23 upon the top of cone member IE to displace the sand and debris 38 from around top collar 8. Rupturing the closures or disks 25 is accomplished by the force of an explosive and preferably from within top collar 8. To this end an elongated body of explosive 3| preferably a length of detonating cord such as that commercially obtainable under the name of Primacord, is lowered through pipe string 5 to the immediate vicinity of ports 23 within the packer head 8 as shown in Figures 2 and 3. The explosive 3| is then detonated in known manner, blowing out frangible disks 25 and forcing thereby a high velocity fluid jet into the surrounding annulus containing the settlings. Fluid is then pumped under pressure through pipe string 5 to be discharged through ports 25 to jet out the settled sand and debris 30 which will have been already loosened to some extent by the shock of the explosive and by the jet blasts therefrom issuing through ports 23.

By way of illustration the explosive may be lowered on a suitable conductor cable 33 having a detonating cap 34 connected to the lower end thereof and detonate electrically within the lower end of the pipe string 5 adjacent the packer head 8 in the manner and by means of apparatus disclosed in the patent to Alexander No. 2,414,349.

In order to confine the explosive to the area adjacent the frangible closures 25 and to limit the outlet of the flushing fluid to ports 23 it is, as hereinbefore mentioned, usually desirable to block off the passage from the pipe string 5 at some suitable point below the ports 23. This may be done at any place in the packer mandrel but a convenient place is in the upper end of the tail pipe. Hence by providing a tail pipe H with a stop shoulder as at l8, blocking of the passage is readily accomplished by lowering or dropping into the pipe string a suitable plugging device such as, for example, a check valve as shown at 35. The check valve shown is of the ball cage type which seats on shoulder l8 and is provided with an upwardly extending conical point 36 by which it can, if desired, be fished out by well known means after the packer has been released. While blocking of the passage below the packer is not always necessary, it is under some conditions a desirable step in the hereindescribed method of freeing a sanded-in packer.

Figure 2 illustrates the method up to the point of firing the explosive since the check valve 35 is already in place in tail pipe I l and a length of detonating cord 3| has been lowered within top collar 8. The remaining steps are to detonate the explosive and then pump flushing fluid, such as drilling fluid, oil or the like suitable liquid, out through ports 23 which have been opened by rupture of frangible disks 25 by the explosive. Since the explosion to a large extent takes place within the packer itself, it vibrates and tends to loosen all parts which are interlocked with each other or with the well casing 6, thus further facilitating the freeing of the stuck or wedged packer. Once the packer head ii is relieved of the grip of packed and hardened sand and drilling mud, permitting upward movement of the valve member 2!} and the packing sleeve 2'1 relative to the slip cone member 9, pipe string 5 can aezaaae be: raised to. loosen the) slips and then, to. elevate: the packer in the casing or to bring it. to the surface. inv the usualmanner.

Eor convenience of illustration, the invention. has hereinbefore been described in connection with a by-pass circulation type of hook-wall packer, but obviously the invention is'equally applicable to non by-pass and other types of packers in; which the sanding-up or sticking of the upper elements thereof prevents the upward release of the packings and the wall gripping elements.

It is, therefore, to be understood that theforegoing is illustrative only and that theinvention' is not limited thereby but may include various modifications and changes made by those skilled, inthe art without departing from the spirit andscopeofthe invention as defined in theappended claims.

What is claimed is:

1. In a well packer having an annular packing body, casing gripping means to support the lower" end of said packing body, and a hollow packer head member to apply longitudinal compressive force through said packing body to said casing gripping means to expand said packing body radially into sealing contact with a surrounding casing, the combination comprising: a lateral duct extending through the wall of said packer head member from the interior to the exterior thereof and directed toward a point adjacent the top surface of said annular packing body; a frangible member in said duct and initially closing said duct against flow of fluid therethrough and adapted to be ruptured upon application of a predetermined pressure differential thereacross.

2. In a well packer having a tubular mandrel, an annular packing body surrounding said mandrel, casing gripping means to support the lower end of said packing body, and a hollow packer head member, connected to said mandrel, to apply longitudinal compressive'force through said packing body to said casing gripping means to expand said packing body radially into sealing contact with a surrounding casing, the combination comprising: a lateral duct extending through the wall of said packer head member from the interior to the exterior thereof and directed toward a point adjacent the top surface of said annular packing body; a frangible member in said duct and initially closing said duct against flow of fluid therethrough and adapted to be ruptured upon application of a predetermined pressure difierential thereacross; and closure means lowerable through said packer head member to close the passage leading through said head member and mandrel at a point below said head member.

3. Apparatus according to claim 1 and explosive means locatable within said packer head member to apply a rupturing differential pressure to said frangible member.

4. Apparatus according to claim 2 and explosive means locatable within said packer head member to apply a rupturing differential pressure to said frangible member.

5. In a well packer, the combination comprising: a mandrel; an annular packing body surrounding said mandrel; casing gripping means on said mandrel and adapted to support the lower end of said packing body when in gripping engagement with a surrounding casing; a hollow packer head member on said mandrel above said packing body, movable longitudinally with respect to said casing gripping means and positioned to? apply downward longitudinal compres sive: force through said packing body to said: casing; gripping means whereby said packing body may be expanded radially into sealing contactwith a surrounding casing; at least one laterally directed duct extending through the wall of said packer head member from the interior to the. exteriorv thereof adjacent the top of said packing'body; and closure means in said duct-normally closing said duct to passage therethroughof fiuid but adapted to open upon application of;

sufiicient differential pressure between the. inside;

and. outside of said packer head.

6.. In a. well packer, the combination comprising; a. mandrel; an annular packing body surrounding said mandrel; casing gripping means: onsaid mandrel and adapted to support thelower end of. said packing body when in gripping engagement with a surrounding casing; a hollow packer head member on said mandrel above said: packing body, movable longitudinally with; re-: spect to said casing gripping means and post tioned to apply longitudinal compressive force; through said packing body to said casinggripping:

. closing said duct to passage therethrough of fluid but adapted to rupture upon application of sufficient difierential pressure between the inside: and outside of said packer head.

7. In a well packer, the combination comprising: a mandrel; an annular packing body surrounding said mandrel; casing gripping means on said mandrel and adapted to support the lower end of said packing body when in gripping engagement with a surrounding casing; a hollow packer head member on said mandrel above said packing body, movable longitudinally with respect to said casing gripping means and positioned to apply longitudinal compressive force through said packing body to said casing gripping means whereby said packing body may be expanded radially into sealing contact with a surrounding casing; at least one laterally directed duct extending through the wall of said packer head member from the interior to the exterior thereof adjacent the top of said packing body; and frangible closure means in said duct normally closing said duct to passage therethrough of fluid but adapted to rupture upon application of explosive force applied from within the packer head.

8. In a well packer, the combination comprising: a mandrel; an annular packing body surrounding said mandrel; casing gripping means on said mandrel and adapted to support the lower end of said packing body when in gripping engagement with a surrounding casing; a hollow packer head member on said mandrel above said packer body, movable longitudinally with respect to said casing gripping means and posi tioned to apply longitudinal compressive force through said packer body to said casing gripping means whereby said packing body may be expanded radially into sealing contact with a surrounding casing; at least one duct extending through the walls of said packer head member from the interior to the exterior thereof in a downwardly diverging direction toward the top of said packer body; and frangible closure means in said duct normally closing said duct to passage therethrough of fluid but adapted to rupture upon application of explosive force applied from within the packer head.

9. In a well packer, the combination comprising: a tubular mandrel; an annular packing body surrounding said mandrel; casing gripping means on said mandrel and adapted to support the lower end of said packing body when in gripping engagement with a surrounding casing; a hollow packer head member on said mandrel above said packer body, movable longitudinally with respect to said casing gripping means and positioned to apply longitudinal compressive force through said packer body to said casing gripping means whereby said packing body may be expanded radially into sealing contact with a surrounding casing; at least one duct extending through the walls of said packer head member from the interior to the exterior thereof in a downwardly diverging direction toward the top of said packer body; frangible closure means in said duct normally closing said duct to passage therethrough of fluid but adapted to rupture upon application of explosive force applied from within the packer head; and means lowerable through said packer head member to close the passage leading through said packer head member and said mandrel.

10. A method for freeing a sanded-in packer having at least one duct extending through the wall of a hollow head member thereof and directed toward a point adjacent the top of said packer, said duct being initially closed by frangible closure means, comprising: lowering a body of explosive into said head member to a position adjacent the inner end of said duct; and detonating said explosive whereby said frangible closure means is ruptured and a fluid jet propelled by said explosive is projected from said duct into the space surrounding said head member adjacent the top of said packer.

11. A method for freeing a sanded-in packer having at least one duct extending through the Wall of a hollow head member thereof and directed toward a point adjacent the top of said packer said duct being initially closed by frangible closure means, comprising: lowering a body of explosive into said head member to a position adjacent the inner end of said duct; detonating said explosive to rupture said frangible closure means and to propel a fluid jet from said duct into the space surrounding said head member adjacent the top of said packer; and subsequently forcing a quantity of a flushing fluid through said duct.

KEITH H. MINER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,926,017 Wells Sept. 5, 1933 2,005,955 Renouf June 25, 1935 2,043,340 Tilbury et al. June 9, 936 2,061,289 Phipps Nov, 17, 1936 2,121,059 Hagan et al June 21, 1938 2,177,886 Halliburton Oct. 31, 1939 2,191,750 Brown Feb. 27, 1940 2,307,658 Appleby Jan, 5, 1943 2,330,144 Powers Sept. 21, 1943 2,343,076 Otis et a1 Feb. 29, 1944 2,397,473 Crowell 1- Apr. 2, 1946 2,414,349 Alexander Jan. 14, 1947