Releasable anchor
The present disclosure relates to a releasable anchor, which may be used in a thermal wellbore, such as a SAGD wellbore. The anchor may be combined with a retrievable packer assembly that mechanically locks and seals into a profile sub. The packer assembly can convert to a bridge plug and be run in place with a liner to isolate the wellbore during the liner setting stage or it can be run into a pre-installed profile sub during a work-over stage in conjunction with a production/injection string to divert flow through a particular section of production liner string. The packer assembly may then be retrieved, and the hydraulic anchor released, allowing movement as a result of any thermal liner pipe expansion, while the thermal element on the liner top packer stays set and sealing within the parent casing.
1 . A method of installing a liner in a wellbore having an intermediate casing, with a completion assembly comprising a liner connected below a liner top packer and a releasable anchor, wherein a profile packer assembly is positioned within the releasable anchor, and the releasable anchor comprises: a cylindrical mandrel defining an inner volume; a top sub attached to an upper end of the mandrel, the top sub comprising a connection for coupling the liner top packer; an anchor ring fixed to an outer surface of the mandrel and an upper cone slidably moveable between a running position and an activated position, wherein activation elements are disposed between the anchor ring and the upper cone, defining a sealed activation chamber between the activation elements and the mandrel, which activation chamber is in fluid communication to the mandrel inner volume through at least one port, wherein expansion of the activation chamber causes the activation elements and the upper cone to move to their activated position; a lower cone fixed to the mandrel and a bottom housing fixed to a lower end of the lower cone by at least one shear pin, wherein the bottom housing is couplable to the profile packer; a slip assembly comprising slips actuatable between the upper cone and the lower cone; a collet adapter affixed to a lower end of the mandrel and disposed within the bottom housing, the collet adapter having downwardly extending collet fingers; and a shift ring slidably moveable within the collet adapter between a non-released position where the shift ring retains the collet fingers against an inner surface of the bottom housing, preventing longitudinal movement of the bottom housing relative to the mandrel, and a released position where the collet fingers may collapse to disengage the bottom housing, permitting longitudinal movement of the bottom housing relative to the mandrel;
and wherein the method comprises the steps of:
(a) positioning the liner top packer at a lower end of the intermediate casing;
(b) landing a ball in the profile packer assembly and pressuring up the wellbore to activate the releasable anchor to engage the intermediate casing and to activate the packer to seal against the intermediate casing;
(c) retrieving the profile packer assembly; and
(d) releasing the releasable anchor with a shift tool, leaving the liner connected to the liner top packer in an energized, pressure-competent state isolating the wellbore below the liner top packer.
2 . The method of claim 1 , wherein the completion assembly comprises a shift tool, and the profile packer assembly is retrieved and the releasable anchor released in a single trip.