METHOD FOR SLIT-FORMATION IN WELLS AND BORE PITS AND SLIT-FORMER THEREFOR Russian patent published in 2016 - IPC E21B43/26 

FIELD: mining.

SUBSTANCE: invention relates to mining, specifically to drilling rocks, and can be used for drilling wells or boreholes (hereinafter wells) by way of initiating slits in rock mass for further hydraulic fracturing for softening or degassing. Method involves well drilling and subsequent slit-forming by cutting initiating slit by means of proposed slit-former. Device consists of a housing with longitudinal window and a knife is installed move in guide slope and exit of its cutting part from longitudinal window of housing. Guide slope is made on inner surface of housing, and knife is installed on a piston arranged inside housing with possibility of axial movement. In cavity of piston there is a booster valve, and between piston and housing there is a return spring. On head part of housing there is a drilling bit, through central hole of which passes a pusher having a rigid coupling with a check valve installed in end parts of housing and drilling bit. Sub-valve cavity of check valve is connected with below-piston cavity, and pusher is installed with possibility of contacting bottom part of well and movement in axial direction.

EFFECT: higher efficiency and reduced cost of slit-formation method during well drilling and slit-formation therein using disclosed slit-former.

2 cl, 2 dwg