METHOD FOR LOWERING A CASING COLUMN INTO HORIZONTAL SHAFTS OF A LARGE LENGTH UNDER CONDITIONS OF DIFFERENTIAL CLAMPING Russian patent published in 2020 - IPC E21B21/08 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, namely to technology of construction of deep oil wells, in particular, to casing column to horizontal shafts of large length in complex mining and geological conditions. At running-in of a countersunk column into a horizontal shaft of a large length, which is drilled in a productive reservoir bed with an abnormally low value of bed pressure of the oil deposit in the unit connecting it to the transport column, placing the shutoff-rotary valve in the "closed" position, and as the descent is made, the pipe space is filled to the design level. When the casing string reaches the depth of the shoe of the production string, the lowering is stopped, the valve is opened, levels are leveled in the pipe and annular spaces, which is ensured by hydrodynamic equilibrium in the "well-reservoir" system. Further, in the conditions of the formed equilibrium, the casing string is lowered to the planned bottom of the horizontal well.

EFFECT: improving efficiency of development of oil and gas deposits by horizontal drilling in complex mining and geological conditions, namely abnormally low bed pressure of oil deposit.

1 cl, 2 dwg, 1 tbl