METHOD OF DRILLING AND DEVELOPMENT OF OFFSHOOT FROM HORIZONTAL WELL (VERSIONS) Russian patent published in 2019 - IPC E21B7/04 E21B43/27 

FIELD: construction.

SUBSTANCE: group of inventions relates to the field of construction of multi-hole wells. Before drilling the offshoot the distance to the water-bearing bed is determined. During lowering the assembly of the tubing string is equipped with three starting couplings. After lowering the assembly on the tubing string in the offshoot sidetracking interval the wedge-deflector is oriented. At the wellhead from the bottom up the assembly is assembled: milling cutter, screw downhole motor (SDM), hydraulic emergency disconnector. Assembly is lowered to the tubing string on the flexible pipe string. 10 m before the cutter-bore bit of the wedge-deflector is started, the SDM is started and with the process fluid pumping through the flexible pipe string are included in the wedge-deflector arrangement in the offshoot sidetracking interval. Side hole is drilled to the bottomhole with load on the cutter bit to 1.5 t. During drilling of the offshoot, compression is performed in a circle by feeding nitrogen into the annular space through starting couplings into annular space with aerated spent process fluid. After the working hole of the offshoot is reached, the drilling process is stopped and the assembly is lifted on the flexible pipes. String of flexible pipes with a jet nozzle at the end to the depth of the drilled bottom of the offshoot is lowered into the tubing string. Simultaneous movement of the string of flexible pipes up to the interval of sidetracking and injection of solution of inhibited hydrochloric acid 22–24 % concentration into the flexible pipe string is carried out acid treatment of the offshoot bottomhole zone with simultaneous jet cutting of channels in the lateral shaft. If minimum distance h from side hole to water-bearing bed is 4 m and more, then jet cutting of channels in side barrel is performed with specific consumption of solution of inhibited hydrochloric acid per 1 m of treatment interval equal to 0.05 m³/m per each hole of jet nozzle. Well head pressure in the mode of cutting and forcing process fluid is equal to 21.0–25.0 MPa. If the minimum distance h from the side hole to the water-bearing formation is less than 4 m, the jet cutting of the channels in the side barrel is carried out with specific consumption of acid per 1 m of the processing interval equal to 0.025 m³/m per one hole of jet nozzle. Well head under mode of cutting and forcing-through with process fluid is equal to 15.0–20.0 MPa. After acid treatment of side barrel, solution of inhibited hydrochloric acid is treated with process fluid via flexible pipe with complete replacement of flexible pipes.

EFFECT: higher reliability of method due to exclusion of clamping of assembly, higher efficiency and quality of acid treatment of sidetrack, as well as exclusion of watered drilled offshoot during acid treatment and creation of emergency situation in well.

2 cl, 6 dwg