US3460624A - Thru-tubing bridge plug - Google Patents

Description

Aug. 12, 1969 J. AITKEN Er-AL 3,460,624

THRUTUBING BRIDGE PLUG Aug. 12,1969 JUTKEN Em 3,460,624

THRUTUBNG BRIDGE PLUG Filed April 14, 1967 2 Sheets-Sheet 2 l 7a f V /7 Zaan 0a/J Pfau/@fw INVENTUM United States Patent O 3,460,624 THRU-TUBING BRIDGE PLUG John Aitken and Jean-Louis Droulers, Caracas, Venezuela, assignors to Schlumberger Technology Corporation, Houston, Tex., a corporation of Texas Filed Apr. 14, 1967, Ser. No. 630,863 Int. Cl. E21b 33/134, 23/00 U.S. Cl. 166-285 16 Claims ABSTRACT F THE DISCLOSURE This invention relates generally to well tools and more particularly to a packer or plug which can be lowered into a well through tubing and then set to pack off a well conduit below the lower end of the tubing.

Prior art devices of this character, that is, so called thru-tubing packers or plugs, have experienced diiculties in forming an effective pressure bridge which will prevent liuid ow within a well conduit. Such devices ordinarily include an inflatable bag which can be inflated by a cementitious material under pressure. After the ce mentitious material hardens or sets up, the bag forms a plug in the well conduit to block fluid flow.

Some of the diculties have arisen due to the fact that since there is a waiting time involved to permit the cementitious material to set up, the bag has been susceptible to disturbance by fluid which may be produced into the well conduit. That is to say, the production of iluid may cause a pressure differential to be built up across the bag before the cement hardens which tends to force liuids past the bag. lf this occurs, such flow can form channels between the bag and the well conduit wall which destroy the plugs effectiveness in holding pressure. Other prior problems have arisen due to the fact that such devices have not been effectively anchored to resist movement in the well conduit in response to such pressure differentials, and have not been arranged so that a particularly uidtight seal is formed against the conduit to prevent leakage.

Accordingly, it is an object of the present invention to provide a new and improved well packer or plug of the thru-tubing type.

Another object of the present invention is to provide a new and improved well packer or plug of the type described which is effectively anchored against movement cannot be developed across it while it is being formed, thereby eliminating the possibility of channeling.

Another object of the present invention is to provide a new and improved well packer or plug of the type described which is effectively anchorde against movement in the Well conduit in response to force which may be imposed upon it in either longitudinal direction.

Another object of the present invention is to provide a new and improved well packer or plug which is arranged to form a tight bond with the well conduit to prevent any uid leakage past its sealing point under pressure.

Yet another object of the present invention is to provide a new and improved packer or plug which is simple and reliable in operation and inexpensive to manufacture.

These and other objects are attained in accordance with the concepts of the present invention by providing a support around which a packing means is mounted. The packing means is adapted for inliation by an initially fluent material which is capable of subsequent hardening and which is contained within a chamber means coupled to the support. Means are provided for selectively forcing the material into the packing means to inflate it and thereby expand the packing means to sealingly engage a well conduit. A vent passageway is provided to extend through the packing means and which functions to temporarily prevent the development of pressure dierentials across the packing means while the fluent material hardens. The vent passageway can be closed when desired.

The invention has other objects and advantages which will become apparent in connection with the following detailed description. The novel features of the present invention being set forth with particularity in the appended claims, the present invention, both as to its organization and method of operation, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in which:

FIGURE l is a longitudinal sectional view of an embodiment of an apparatus for practicing the present invention with the parts in retracted position for lowering into a well;

FIGURE 2 is a view similar to FIGURE 1 with various parts in expanded positions for plugging a well conduit;

FIGURE 3 is a sectional view of the apparatus of FIGURE 1 and of parts of the present invention which remain in the well conduit to form a plug therein;

FIGURE 4 is an enlarged cross-sectional view of certain parts of the present invention in lowering positions; and

FIGURE 5 is a sectional view with portions in side elevation of a packing means in accordance with the present invention.

Referring initially to FIGURE 1, an embodiment of the present invention includes a bag section A coupled at its lower end to an inating section B and coupled at its upper end to an anchor section C. A setting tool assembly D is releasably connected to the anchor section C and the entire tool can be suspended on an armored electrical cable 10.

The bag or plug section A includes a central support tube 11 having a bore 12 therethrough providing a vent passageway which extends between a lower side port 13 and several upper side ports 14. The support tube 11 can have a stepped portion 15 around which the lower end of an inflatable, expansible bag 16 is mounted, the lower end of the bag being secured to the portion 15 by a Suitable clamp 17. rIhe upper end of the bag 16 is similarly secured to a sliding sleeve 18 which can move downwardly along the support tube 11, fluid leakage -between the sleeve and the support tube being prevented by a suitable seal element 20. The bag 16 can be constructed of a suitable material such as neoprene impregnated Daeron cloth so as to be readily pliable as Well as substantially impermeable. The bag 16 can have longitudinal or spiral folds (not shown) formed therein for reducing its diameter while enabling it to be expanded to a well conduit diameter of several times its folded size.

The inflating section B includes a tubular housing 21 having a chamber 22 therein adapted to contain an inflating medium 23 such as cement or plastic which is initially uent but which is capable of hardening after a predetermined span of time. The chamber 22 is placed in communication with the interior of the bag 16 by an inflation passageway 24. A lluid displacing piston 25, which can take the exemplary form of a conventional swab, is normally positioned at the lower end of the chamber 22 and is capable of displacing or forcing the medium 23 through the inflation passageway 24 and into the bag 16 upon upward movement of the piston within the chamber. A piston actuating member in the form of a pull wire 26 can be connected to the piston 25 and extend upwardly into the vent passageway 12 through a packing gland 27, the wire 26 continuing upwardly and then exiting through one of the upper vent ports 14. It will be appreciated that an upward pull on the actuating wire 26 can move the piston 25 upwardly and displace the medium 23 into the interior of the bag 16 to intlate it.

It is desirable that once the inflating medium has been displaced into the bag 16 that no return movement of the medium into the chamber 22 be permitted. To this end, a check spring 28 can be fastened to the bottom end of the swab piston 25 and include downwardly curved, resilient lingers 29 which are adapted to permit upward movement of the swab piston but which will grip the chamber walls to prevent any return or downward movement. Alternatively, a conventional one-way check valve (not shown) could be arranged in the inllation passageway 24 for performing the same function.

The anchor section C includes an annular shoulder or flange 31 which can be integrally coupled to the support tube 11 and which carries a plurality of outwardly extendible anchor arms 32. The anchor arms 32 are formed in pairs with each upper arm pivotally connected by a pin 33 to a collar 34 which is slidably mounted on the support tube 11. The lower one of each pair of arms 32 is pivotally connected by a pin 35 to the flange 31 and the arms are additionally pivotally connected by pins 36 to one another. The outer end of each arm 32 is provided with wickers or teeth 37 adapted to bite into and grip a well conduit upon being extended into engagement there with. Extension of the arms 32 can be elfected by advancement of the collar 34 along the support tube 11 toward the flange 31, causing the arms 32 `to pivot and extend outwardly. Any premature advancement of the collar 34 can be prevented by a shearable pin connection 3S between the collar 34 and the support tube 11.

In order to prevent premature expansion of the bag 16 while lowering into a well, the sliding sleeve 18 can be releasably coupled to the support tube 11 as shown Iin FIGURE 4. In the form illustrated, the sliding sleeve 18 has an upwardly projecting tang 40 having an aperture 41 therein. A dog 42 on one of the lower anchor arms 32 can extend into the aperture 41. The cooperation between the dog 42 and tang 40 serves to prevent any downward motion of the sliding sleeve 18 as long as the anchor arms are in retracted positions. During setting, however, it will be appreciated that as the lower arm pivots outwardly about the pin 33, the dog 42 is withdrawn from the aperture 41 and the sleeve 18 is then free to move downwardly on the support tube 11.

An annular setting head 45 is slidable on the support tube 11 above the collar 34 and a suitable biasing means 46, for example several stacked disc springs, can be positioned intermediate the head and collar for transferring force from the head to the collar while permitting a limited amount of relative motion therebetween. The setting head 45 has an internal annular recess 47 therein forming an inclined surface which is cooperable with outer inclined surfaces of a locking slip 48, the locking slip 48 having teeth 49 on its inner periphery engageable with the outer surface of the support tube 11. The locking slip 48 is arranged to function as a one-way clutch and to permit downward movement of the setting head 45 relative to the support 4tube 11 for extending the anchor arms 32 and to prevent converse relative movement for maintaining the anchor arms extended.

Releasably coupled to the upper end of the tool is the setting tool assembly D. The setting tool assembly D is conventional and familiar to those skilled in the art, an exemplary embodiment being shown in U.S. Patent No.

2,618,343. The setting tool can be selectively actuated by an electrical signal through the cable 10 and is capable of exerting upward force on the support tube 11 through a threaded tension member 50 which is threadedly engaged with the support tube. Simultaneously, downward force is exerted on the setting head 45 through a compression sleeve 51. Such forces can cause the setting head 45 to be advanced relatively downwardly along the support tube 11 and toward the flange 31 to expand or extend the anchor arms 32 outwardly Iinto engagement with the well conduit wall. When a predetermined magnitude of setting force is built up in the tension member 51), it will break in tension at a reduced neck portion 52. When the neck portion 52 breaks, the setting tool assembly D is freed from its connection to the upper end of the support tube 11 and can be hoisted upwardly within the well by an upward pull exerted on the cable 10 at the earths surface.

For selectively closing olf the side vent ports 14, a sleeve val-ve can be positioned between the compression sleeve 51 and the support tube 11 and adapted to slide on the support tube adjacent to the side vent ports 14. Suitable sealing elements 61 and 62 are arranged to seal between the valve 60 and the support tube 11. When the valve 60 is in its lower position shown in FIGURE 2, the vent ports 14 are open for flowing fluids. However, when the valve 60 is reciprocated upwardly, the seal elements 61 and 62 will seal above and below the vent ports 14 to close off the ports to any llow.

An upper portion 63 of the sleeve valve 60 has its inner surface spaced laterally away from the outer surface of the support tube 11 to form a passage space through which the piston actuating Wire 26 can extend. The terminal end of the wire 26 `can be connected to the setting tool tension member 50 by a suitable fastening device 64. Additionally, the upper end of the valve 60 is provided with a connector head 65 which is arranged so that when the setting tool assembly D is eventually removed from the well, a grapple or other suitable means (not shown) can be lowered and connected to the connector head for pulling the sleeve valve 60 upwardly to its closed position.

Operation In operation of the apparatus, the tool can be prepared for lowering into the well by assembling the tool as shown in the drawings and lilling the chamber 22 with a selected volume of inflating medium 23. The entire tool is then suspended on the cable 10 and lowered through a tubing string T to a selected setting point within a well casing C below the lowermost end of the tubing string. Since the bag 16 is in its folded condition and the anchor arms 32 are retracted, the entire tool can have a relatively small maximum outer diameter such as 111/16" for passing through small size tubing. However, when the tool is positioned below the lower end of the tubing string, the bag 16 and anchor arms 32 can be expanded and set in a relatively large size casing C which may be, for example, 51/2 or 7".

When desired, an electrical signal applied to the cable 10 will activate the setting tool assembly D for extending the anchor arms 32. As previously described, the cornpression sleeve 51 is moved downwardly relative to the support tube 11 to advance the setting head 45 toward the support tube ange 31. As this occurs, the anchor arms 32 are pivoted outwardly until the teeth 37 on their outer ends firmly grip the well casing C as shown in FIG- URE 2. The locking slip 48 will grip the outer surface of the support tube 11 to hold :the setting head 45 in the lowermost position to which it is moved, thereby locking the anchor arms 32 in their extended positions. When a predetermined magnitude of setting force is built up in the setting tool tension member 50, the tension member will part or break at the reduced neck portion 52 to release the setting tool assembly D for upward movement in the well bore. The piston actuating wire 26 remains connected to the tension member 50, however.

To inflate and expand the bag 16, the setting tool assembly D is moved upwardly by upward pull on the cable at the earths surface. Upward motion of the setting tool is translated by the wire 26 to the swab piston 25 and upward motion of the piston will displace or force the fluent material 23 into the bag 16 through the inflation passageway 24. As the bag 16 expands, the sliding sleeve 18 can move downwardly on the support tube 11 to accommodate changes in the length of the bag. The amount of tension in the cable 10 can be used to control the inflation pressure built up inside the bag 16 lto insure that an elfective seal is formed against the well casing wall. It will be appreciated that the bag section A will not rnove upwardly in response to upward pull on the cable 10 because of the holding action of the anchor arms 32.

The chamber 22 can be appropriately dimensioned so that a volume of inflating medium in excess of that required to fully inate the bag can be overflowed or dumped on the top side thereof to increase the overall length of plug formed in the casing. To this end, an overflow passageway 70 can be formed in the sleeve 18` to extend from the interior of the bag to a location above the bag. A suitable pressure actuated check valve 71 can be placed within the overflow passageway 70 and arranged to open the passageway only in response to a pressure greater than a predetermined inflation pressure for the bag 16. Accordingly, after the bag 16 is `fully inflated and in sealing engagement with the well casing, the valve 71 will automatically open and the remaining volume of medium within the chamber 22 displaced through the bag 16 and dumped or deposited on top ofthe bag. When all the medium has been displaced from the chamber 22 by the swab piston 25, the check valve 71 will close the passageway 70 to trap a desired inflation pressure within the bag and the material both within the bag and on its top side can set up into la solidified mass.

If desired, inflation pressure could be maintained within the bag 16 by merely applying constant tension to the cable 10 and can be maintained for a suicient length of time to allow the medium 23 to harden into a solid mass. After the material has hardened within the bag 16, an over pull on the cable 10 will serve to part the actuating wire 26 and the setting tool assembly D can be withdrawn from the well. On the other hand, inasmuch as the check valve 71 will close at inflation pressure and since the fluent material cannot return into the chamber 22 as previously described, the actuating wire 26 can be immediately broken and the setting tool assembly D withdrawn from the well without waiting for the medium 23 to harden.

In any event, it will be noted that during the entire time that the medium 23 is hardening, the vent passageway 12 and the upper and lower ports 14 and 13 are open. Accordingly, if a zone below the plug is producing uid, the fluid can pass through the bag 16 via the passageway 12 and such fluid low will not disturb the bag. When desired, a suitable grapple (not shown) can be lowered through the tubing string and coupled to the connector head 65 so that the vent valve 60 can be moved to its upper position for closing the vent ports 14 as shown in FIGURE 3. It will also be appreciated that the vent valve 60 is arranged to be pressure balanced so that it will not open in response to pressuhe from above or below.

It is desirable to cause the bag 16 to firmly bond against the well casing C to prevent any uid leakage past the bag. This can be accomplished in accordance with the present invention by particularly forming the bag 16 as shown in FIGURE 5 to have a midsection 73 which is constructed of a slightly porous cloth which is not impregnated with neoprene as are the upper and lower portions 74 and 75 of the bag. In response to inflation pressure built up within the bag 16, a small amount of the inflating medium 23 can seep or leak through the porous midsection 73 and function to bond or stick the bag to the well casing.

Moreover, to further insure that lthe plug will not move longitudinally in the well casing after the medium 23 has hardened, the bag 16 can be selectively positioned within the well casing C at a setting point which is at a collar joint 78 as shown in FIGURE 2. Accordingly, when the bag 16 is inflated, an annular portion 79 will extrude under pressure into the internal annular recess 80 formed by the collar joint 78 and function, in addition to the anchor arms 32, to hold the tool against movement in response to pressure from above or below.

Instead 4of using the overflow procedure as previously described for depositing medium on top of the bag 16, it will be appreciated that a batch of additional cementitious material can be deposited by a conventional dump bailer (not shown) on top of the bag 16 and allowed to harden to provide for additional overall length of the plug. If additional material is used in this manner, the vent valve 60 can be left in its open position to insure that the material will remain undisturbed as it hardens. When desired, the valve can be closed as previously described. In either event, it will be appreciated that the additional material deposited on top of the bag can further insure that the plug will remain immovable in the well and can withstand high pressure differentials acting from either direction.

A new and improved well packer or plug has been disclosed which can be lowered through tubing and set in a well casing. The tool is arranged to prevent channeling of fluids as the plug is being formed and is effectively anchored in a manner to provide a leakproof seal which will prevent fluid ow in either direction in the well. Since certain changes may be made in the disclosed embodiment without departing from the inventive concepts involved, it is intended that the appended claims cover all changes or modifications falling within the true spirit and scope of this invention.

We claim:

1. A well packer apparatus comprising: a support; packing means around said support adapted to be inflated by an initially uent medium which is capable of subsequently hardening; chamber means coupled to said support in fluid communication with said packing means and arranged to contain said medium for inilating said packing means; means in said chamber means for forcing said medium through said passageway and into said packer means to inflate said packing means; a vent passageway in said support extending between locations in communication with the well bore above and below said packing means for temporarily permitting fluids in the Well bore to How through said packing means while said medium is hardening; and valve means for selectively closing olf said vent passageway.

2. The apparatus of claim 1 further including pressure actuated overflow means operable at a predetermined pressure at least as great as the inflation pressure of said packing means for depositing a volume of said material on the top side of said packing means.

3. The apparatus of claim 2 wherein said chamber means includes a tubular member having a bore for containing said fluent medium, said bore being in communication with said inflation passageway, and wherein said forcing means includes a piston member movable within said bore.

4. The apparatus of claim 3 further including means for trapping said medium at inflation pressure within said packer means.

5. The apparatus of claim 1 further including anchor means on said support shiftable outwardly thereof into engagement with a well conduit; and power means for shifting said anchor means outwardly.

6. The apparatus of claim 1 wherein said chamber means is coupled to said support on one side of said packer means; and a member extending through said support to the other side of said packer means for actuating said forcing means.

7. The apparatus of claim further including releasable means for connecting said power means to said support, said releasable means being arranged to release said power means from said support after said anchor means have engaged a well conduit wall so that said power means can be withdrawn from the Well.

8. Apparatus for use in packing oli a well bore comprising: a support tube; packer means on said support tube adapted to be inflated and thereby expanded to pack off a well bore; anchor means on said support tube arranged to be extended into anchoring engagement with a well conduit wall; irst power means coupled to said support tube for 4extending said anchor means; chamber means coupled to said support tube and adapted to contain a fluent medium, said chamber means being in fluid communication with said packer means; second power means for dispacing said uent medium into said packer means to inflate said packer means; and selectively closable passage means extending between locations in cornmunication with the well bore above and below said packer means for temporarily providing a iiuid passageway through said packer means in its expanded condition.

9. The apparatus of claim 8 further including a releasable connection between said rst power means and said support tube arranged for releasing said first power means for longitudinal movement in the well bore after said anchor means is extended.

10. The apparatus of claim 9 further including means for coupling said iirst power means to said second power means, said coupling means being arranged to actuate said second power means in response to said longitudinal movement of said first power means.

11. The apparatus of claim 8 further including means for locking said anchor means in an extended condition.

12. The apparatus of claim 8 wherein said closable passage means includes a side port in said support tube; and further including sleeve valve means having sealing elements arranged to seal against said support tube above and below said side port.

13. The apparatus of claim 8 further including an overlow passageway extending between the interior of said packer means and the well bore space above said packer means; and pressure actuated valve means in said overflow passageway for depositing excess liucnt medium on top of said packer means after said packer means has been fully intlated.

14. An intiatable well packer comprising: a support tube; an intiatable packing means mounted around said support tube and adapted for a wide range of expansion upon iniiation thereof; means securing the ends of said packing means to said support tube in uid-tight relation thereto; an inflation passageway in said support opening into the interior of said packing means and through which uid under pressure can be supplied for inflating said packing means, said packing means being constructed of a pliable material which has impermeable upper and lower portions and a permeable mid-portion whereby a small amount of tiuid under pressure can seep through said mid-portion when the packing means is inflated.

15. A method for bridging a well casing below the lower end of a tubing string in the well casing, said well casing having a collar joint providing an internal annular recess in said well casing, comprising the steps of: lowering a packer member through the tubing and into the casing; locating the packer member at the level of said collar joint; inating said packer member to close off the cross section of said well casing in a manner whereby a portion of said packer member is extruded into said recess formed by said collar joint; then depositing a cementitious material on top of said bridging member and allowing said cementitious material to harden into a solid plug.

16. The method of claim 15 further including the steps of temporarily venting said bridging member so that fluid in the well bore can ow in said well casing from a point below said packer member to a point above said cementitious material; and after said cementitious material hardens, closing off the vent passage.

References Cited JAMES A. LEPPINK, Primary Examiner U.S. C1. X.R. 166-187, 188, 315

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