Patent ID: 6029747
Filing Date: 2000-02-29
Classification: E21B

Abstract:
A method for allowing entry of an existing lateral offshoot from a main borehole, without removal of downstream completion tubing from the main borehole, comprising the use of both a liner (14) and a whipstock (28) inserted through the completion tubing (10) to a position within the liner (14), characterised in that an intermediate device (18) comprising a hollow sleeve being linear along an entire length thereof and having a window (22) positioned between a deflecting surface of the whipstock (28) and an associate window through the liner (14), the intermediate device (18) having at least one part (20b) thereof adapted for sealing abutment with a protrusion (20a) projecting inwardly of the liner (14) so that the whipstock (28) locates with the intermediate device (18) rather than the liner (14) to allow entry of an existing lateral offshoot without removal of the completion tubing.