METHOD FOR ISOLATION OF LOST CIRCULATION ZONE OF DRILLING MUD DURING OIL AND GAS WELLS Russian patent published in 2024 - IPC E21B33/13 C09K8/00 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to a method of isolating a lost circulation zone of a drilling fluid during oil and gas wells. Method includes preparation and pumping of isolating carrier solution with different-fraction filler into absorption zone, then it is displaced under pressure of displacement fluid into absorbing formation. Before the mixture preparation, process water is pumped into the pipe space, having previously raised the drilling tool above the roof of the absorbing formation until excess pressure is obtained. Then the feed line is closed. Then process water is pumped into annular space. Buffer fluid is pumped after service water. After that, prepared insulating carrier solution is pumped through annular space into absorbing formation. After that spacer fluid is pumped. Then, isolating carrier solution is squeezed using displacement fluid. At that, prior to the beginning of operation, as well as during pumping and flushing of the insulating carrier solution, the drilling tool is periodically reciprocated.

EFFECT: considerable reduction of time spent on insulation works, efficiency of insulation works, as well as simplification of insulation works technology.

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