METHOD FOR WELL CONSTRUCTION Russian patent published in 2011 - IPC E21B7/00 

FIELD: construction.

SUBSTANCE: invention relates to oil industry and may find application in well construction. In process of well construction, well direction, conductor and main shaft are drilled, casing and flow strings are lowered and fixed. Direction is drilled with bit of diameter of 490 mm with application of clay drilling agent with density of 1.12-1.20 kg/m³. Conductor drilling is carried out in two stages. At first intermediate conductor is drilled with bit of diameter of 393.7 mm with application of mineralised water as drilling agent with density of 1.16-1.20 kg/m³. When drilling intermediate conductor, every 12 m drifting is carried out, which consists in lifting and lowering of bit with rotation and flushing, and when sticking effect appears, sticking interval is worked on, by pumping of mineralised water, and rotary bit is used to work interval of sticking zone to eliminate sticking effect. At the second stage after drilling of intermediate conductor, a conductor is drilled with bit of diameter of 295.3 mm, and after casing and fixation of conductor, the main shaft of well is drilled with bit of diameter of 215.9 mm.

EFFECT: invention solves problem of well construction under conditions complicated with zones of drilling tool sticking.