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

FIELD: mining.

SUBSTANCE: method for well drilling includes rotation and axial feed of a layout with a chisel and supply of a drilling mud via an inner cavity of the layout for landing, lowering and cementing of a casing string. The well is drilled not reaching the payout bed by 5-40 m, drilling pipes are lowered with a packet at the end. The packet is installed above the lower interval of the absorption zone. A clayey solution is injected along the pipe string into the absorption zone with density of 1.080-1.350 g/cm³, containing a fibrous filler or rubber crumb in the amount of 0.5-3.0 m³ per 10 m³ of the solution with pump capacity of not more than 15 m³/hour until the pressure of 2.8-3.2 MPa is pulled at the well head. Injection is stopped. Well injection capacity is identified. If the injection capacity differs from zero, solution injection is continued, zero injection capacity is achieved. Serially a string of drilling pipes with a packet is lifted into each interval of the absorption zone, and operations are repeated. In the last upper interval they lift the string of drilling pipes with the packet from the well, and the string of drilling pipes with a chisel at the end is lowered with speed of 0.5-1.0 m/s. Via every 300-400 m of lowering the well is washed with drilling mud, which is gradually being replaced. The string of drilling pipes with the chisel is lifted from the well. The drilling layout is lowered, and the well drilling is finalised to the design elevation.

EFFECT: higher efficiency of absorption zones insulation.