METHOD AND DEVICE FOR DEEP PERFORATION OF ENCASED WELL Russian patent published in 1998 - IPC

FIELD: oil production industry. SUBSTANCE: this improves efficiency of perforation due to increased depth and diameter of perforated passage. According to method, cutting tool is positioned radially with respect to wall of casing pipe. Rotation motion and axial feed are imparted to tool. At axial feed, cutting tool receives additional compression force in direction which is opposite to direction of drilling. Device for realizing aforesaid method has cylindrical body and flexible rod with cutting tool which is installed radially inside body. Curvilinear guide member is provided to ensure axial displacement of rod. Device also has feed mechanism and rotation mechanism for rod. Rod is made sectional, it comprises bushes and shells. Bushes have through-holes. Shells are inserted into bushes with clearance and possible prevention of their axial displacement relative to bushes. Each shell is simultaneously inserted into two adjacent bushes. Holes of bushes are other than round in configuration, and configuration of shells repeats configuration of holes. Rope is inserted through bushes and it is spring-loaded by resilient compression member. EFFECT: higher efficiency. 4 c, 3 dwg