LIFTING TOOL WITH WEDGE GRIPS TO RAISE DRILL STRING ASSEMBLY BOTTOM IN PROCESS OF DRILLING OPERATIONS ON CASING STRING

摘要

FIELD: mining.;SUBSTANCE: drill string assembly bottom for drilling on a casing string is connected as capable of release with a casing string. The lifting tool is lowered in the casing string and fixed on the drill string assembly bottom. Wedge grips are installed on the lifting tool and are drawn-in in process of lowering. The pressure difference moves the lifting tool and the drill string assembly bottom upwards, and wedge grips are engaged with the casing sting to prevent downward movement, if the pressure difference reduces too much. The channel stretches via the lifting tool and the drill string assembly bottom. A check valve in the lifting tool provides for flow passage downwards via the channel, but it prevents passage of the flow upwards, therefore, fluid medium may be circulated via the lifting tool and the drill string assembly bottom suspended on wedge grips.;EFFECT: increased efficiency of raising a drilling string assembly bottom.;20 cl, 14 dwg