Patent Application
20120043073
The field of the invention is retrieval tools run on wireline that perform the retrieval in distinct operations using cyclical movements to separate the functions for sequential operation.
Packers and bridge plugs are used to isolate zones in a subterranean location. Retrievable versions of such devices need to be released from sealing and mechanical grips that their components have on the surrounding wellbore. Different types of tools have been developed for such retrieval operations. Some are tubing run and others are delivered on wireline. Generally these tools need to grip and undermine the slips and sealing element that had earlier been set, most likely by compressive forces based on hydraulic pressure or setting down weight, for example.
The set isolation devices can have large pressure differentials acting on them and it is desirable to equalize pressure across such barrier devices before the slips and sealing elements are allowed to relax. Prior designs that have actually employed an equalizing pressure feature before release have done so in one continuous motion where it was hoped that the equalization had sufficiently taken place before the mechanical release. However, since both movements were supposed to be accomplished in the same unidirectional movement, there was a risk that the equalization had not sufficiently taken place by the time the mechanical release took place. If that happened the packer or plug could be propelled and get stuck at another location in the wellbore. If the retrieval tool was run in on tubing, the tubing could be bent and contorted as the packer or bridge plug that had not been fully equalized was propelled uphole upon mechanical release.
Some retrieval tool designs just grabbed the packer or bridge plug and mechanically released it without concern of differential pressure that may be acting on it at the time. Tools using a single jarring motion to release either with or without equalizing and run on wireline or tubing include: US Publication 2009/0000792; U.S. Pat. Nos. 7,036,602; 7,389,823; 4,805,699 (coiled tubing); 4,869,325 (coiled tubing); 6,220,348 (equalize and pull retrieval lugs); 6,244,642 (equalize and pull on retrieval lugs); 5,366,012 (jar and release); 3,714,983 (jar to equalize and release in same motion); 4,044,826 (jar and release); 3,667,543 (jar and operate a j-slot); 6,681,858 (tubing conveyed grapple) and 4,332,410 (release tool jars to break free of stuck packer).
What is needed in a retrieving tool and provided by the present invention is a way to be sure that the operation of equalizing a packer or bridge plug is done at a time and in a way that cannot release the slips and sealing element. More particularly the equalization and subsequent release for retrieval are accomplished with jar movements and intervening pickup force. The equalizing releases a locking dog on a second sleeve whose movement then becomes possible to release the packer or bridge plug and retrieve it. These and other features of the present invention will become more apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the literal and equivalent scope of the appended claims.
The retrieving tool engages an equalizing sleeve on a jar down movement while the packer or bridge plug release sleeve is held fixed with a locking dog. The initial jarring down allows the tool to engage the equalizing sleeve and pull it up subsequent to the initial engagement by jarring down. Pulling or jarring up then opens the equalizing ports while still holding the release sleeve locked using a trapped collet. A subsequent jarring down allows engagement of a second sleeve so that a subsequent pulling or jarring up moves the second sleeve away from the collet that had otherwise held the set position of the packer or bridge plug. A pull or jar force up brings up the now released packer or bridge plug.
The retrieval tool R is brought to the packer or bridge plug P in
The dogs 16 are disposed initially below the recess 34 in mandrel component 20. The primary release sleeve 30 overlays the secondary release sleeve 36 in a manner that lets surface 38 of the secondary release sleeve protrude through a window 40 in the primary release sleeve 30. As seen in
In the
Now referring to
Those skilled in the art will appreciate the presence of the dogs 16 in there supported position prevents the tool R from reaching the secondary sleeve 36 in the initial jarring down. This insures that the equalizing sleeve 44 will be operated first as the primary release sleeve 30 is initially operated to move relatively to the secondary sleeve 36. This relative motion allows the dogs to retract into groove 34 as the sleeve 30 is pulled to its travel stop 62. Now the plug P is equalized but still held firm in the wellbore. A subsequent jarring down now allows the secondary sleeve 36 to be engaged and pulled up until the collet heads 66 are no longer trapped to groove 70. As soon as that happens, the trapped compressive force in the sealing element of the plug P extends as the collet heads 66 no longer retain the sealing element of the plug P in the compressed condition. As a result the collet heads 66 jump out of the groove 70 as shown in FIG. 4. The jar up force takes up the plug P as the surfaces 22 and 38 are held together by having the weight of the plug P trapping them in that relationship against surface 14 of the retrieval tool R.
Those skilled in the art will appreciate that a single jarring direction of the retrieval tool R when connected to the plug P will equalize the plug P without actually releasing it. The release sleeve for the plug P only becomes accessible when the equalizing has been accomplished by the initial jarring up force. It takes a second jarring down and jarring up to engage the plug release sleeve 36 so that the assembly of the retrieving tool R and the plug P can be pulled to the surface. While the equalizing and release in the preferred embodiment is done with sleeves other mechanisms that ensure sequential operation of equalizing before release of the plug are within the scope of the present invention. This is preferably accomplished by blocking access to operating the release mechanism until the equalizing mechanism is operated. More specifically a cycle of jarring down and up takes place before the release can happen in an independent cycle of jarring down and up a second time. Reference to jarring up can also be accomplished by a simple pull on the wireline even without actuation of the attached jar tool. While it is preferred to deliver the retrieval tool R on wireline as an alternative coiled or rigid tubing can be used without departing from the invention.
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below.
