METHOD OF WELL CONSTRUCTION IN COMPLICATED CONDITIONS Russian patent published in 2023 - IPC E21B21/08 

FIELD: construction of oil and gas wells.

SUBSTANCE: invention relates to methods of opening local intersalt layers with abnormally high formation pressure and low reservoir properties. High-pressure local inter-salt interlayers are exposed by drilling on a biopolymer salt-saturated solution with an increase of the density of the drilling fluid when a gas-oil-water intrusion is detected. Drilling is continued to the planned depth using the drilling fluid with a density of 1750 kg/m³, conditional viscosity of 55 seconds and acidity parameter of 9.0-9.5, with a constant two-phase flow at the well outlet and gas flow into the block of receiving tanks with a degasser. Next, the casing string is lowered to the planned depth, flushing is performed to replace it with degassed drilling fluid, the casing string is cemented, and excess pressure is created for the period of waiting for the cement stone to harden.

EFFECT: increased efficiency of drilling wells with the possibility of continuing drilling to the underlying reservoirs of oil and gas without a significant increase in the time of well construction.

1 cl, 1 ex