METHOD FOR CONSTRUCTING SIDETRACK WITH HORIZONTAL ENDING Russian patent published in 2015 - IPC E21B33/14 

FIELD: oil and gas industry.

SUBSTANCE: before shank running-in horizontal ending is filled with clay mud of increased viscosity. The shank is equipped with centralisers in the densest parts in intervals of caving-in areas and is run-in at drill tubes with string disconnector up to interval of the horizontal ending commencement at low rate so that the string is moved constantly. During running-in of the shank the drill mud is levelled periodically. Upon running-in the process is withhold until the shank is set, setting of the shank is controlled, then the shank and borehole annulus are washed, drill tubes are screwed off from the shank, cement head is screwed on, cement solution is pumped through the shank to the borehole annulus and the shank borehole annulus is cemented. Upon running-out of drill tubes the process is withhold for the period of cement setting and hardening, cement remains in the shank and its fittings are drilled out, washed and the well is developed.

EFFECT: preventing accident rate at running-in of the shank in conditions of caving-in rocks in the well.

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