METHOD TO PREVENT CASING PIPE CRUSHING IN WELL DRILLED IN PERMAFROST ZONE Russian patent published in 2007 - IPC E21B36/00 

FIELD: oil and gas production industry, particularly to construct and operate all types of oil, gas and injection wells in permafrost areas.

SUBSTANCE: method involves forming artificial hollow drain channel in proximity to casing pipe wall so that the drain channel extends along casing pipe wall and is located at depth of permafrost ground sitting to discharge excessive water from cavern via he channel. The hollow drain channel is made as non-filtering pipe string filled with water-immiscible frost-resisting liquid having density exceeding that of cavern water. Bottom part of drain channel is provided with check valve, seating socket for valve receiving and with filter, for instance with the use of wireline technique. Excessive water discharge from cavern may be repeatedly carried out without any limit and without power inputs up to full cavern freezing. To prevent ice plug formation in drain channel the channel and water-immiscible frost-resisting liquid column is exposed to ultrasonic action.

EFFECT: decreased costs of method realization due to power source elimination, reduced power inputs and technical means to maintain drain channel in thawed condition.

2 cl, 1 dwg