METHOD FOR WELL DRILLING Russian patent published in 2013 - IPC E21B21/00 E21B7/00 

FIELD: mining.

SUBSTANCE: when drilling a well, a string assembly with a downhole motor is placed in the well, water is pumped through the assembly, drill-pipe connection is carried out, sludge is washed away from the downhole. Sludge washing is carried out by pumping of a drilling mude with viscosity of 30-50 according to a viscosimeter VP-5, density of 1.20-1.30 g/cm³ in the volume of 5-10 m³. In process of pumping the load is taken off the chisel, the string assembly is lifted for the length of the master drill pipe, water in drill pipes is replaced for drilling mud of higher viscosity, the drilling mud is pumped with simultaneous lowering of the string assembly until stop at the downhole, string assembly stroking is carried out with frequency of 1-2 per minute and amplitude equal to the length of the master drill pipe, with simultaneous pumping of the higher density mud, the drilling mud is replaced with water, the drill pipe is connected to the string assembly, drilling is continued. Water is used with initial density of 1.00-1.01 g/cm³. In process of drilling water density is increased due to particles of drilled rock to the density of 1.02-1.06 g/cm³. When opening the water horizon, a mixture of water is used with current density and produced water.

EFFECT: increased efficiency of drilling.

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