RETRIEVABLE WHIPSTOCK Russian patent published in 2015 - IPC E21B7/08 

FIELD: oil and gas industry.

SUBSTANCE: retrievable whipstock comprises a whipstock with inclined working surface made as a groove connected to the whipstock through adaptor of support unit with bottom blind shoe and work chamber, high-pressure flexible hose to supply fluid through the adaptor channel to the support unit. The whipstock is coupled to the support unit so that it may be disconnected at breakage of shearing pins, while the support unit may be expanded at fluid delivery to the wok chamber until it is fixed in regard to walls of the well and be folded when fluid is pumped out from the work chamber with detachment from walls of the well before retrieval. By shearing pins the whipstock is coupled to the cross-over shoe, which is equipped with feedthrough axial opening and upstream thread for tight joint with a hollow puller run in at the pipe sting with a bit complete with radial openings, the puller is inserted into the tip so that it may move only upwards with tight covering of the above radial openings.

EFFECT: reduced probability of whipstock locking and failure of its retrieval from the well, reduced material costs.

3 dwg