Releasable well anchor tool

Abstract

A releasable well anchor adapted to be set on a wire line with a running tool attached which comprises an internal and an external mandrel which are slidably mounted with respect to one another having a set of slips on the exterior which slips have two positions, one position being recessed and the other position being radially outwardly of the first to engage the well pipe thereabout in an anchoring positon. The slips are set on movement of an enlargement on the internal mandrel. A set of flexible collet fingers is attached to the internal mandrel, and positioned near first and second internally located receptacles separated by a surface within said external mandrel. The collet fingers flex outwardly into said first or second receptacles on relative movement between said mandrels wherein relative positioning of said collet fingers in said first or second receptacles define a running in position, a setting position, and a retrieval position. An alternative embodiment utilizes outer and inner mandrels which have interconnecting collet fingers and receptacles in the same manner as the first embodiment. It carries a packer element near the lower end, not the upper end, and the packer element is expanded on manipulation of inner and outer lower mandrels. The lower inner mandrel has a set of collet fingers which have teeth or serrations on the outer surface. The lower outer mandrel incorporates an inwardly facing set of mating serrations. The two sets of serrations cooperate to lock the lower inner and outer mandrels in altered relative longitudinal position, causing expansion of the packer element. They cooperate with the upper outer and inner mandrels to prevent release of the tool on withdrawal of the slip means in the event of bottom hole pressure differential. The apparatus is adapted to be run and set in a manner similar to the first embodiment on a running tool. A third embodiment utilizes inner and outer mandrels which are arranged somewhat differently from the other embodiments.