WELL DRILLING METHOD AND DEVICE Russian patent published in 2006 - IPC E21B7/26 E21B10/44 

FIELD: well drilling, particularly well drilling without earth removal, for instance, by device screwing in ground.

SUBSTANCE: method involves screwing device in ground, perforating and displacing ground in axial, circumferential and radial directions in vertical and horizontal planes with the use of conical head ribs and conical and cylindrical head borer spiral bands, working wedge-like parts of truncated cones of head, intermediate and casing borers. As design well depth is reached head borer is separated from interlocked intermediate and casing borers by crewing up the borers along head body, ground is perforated and displaced to align plane of truncated intermediate borer cone cutoff with base of truncated head borer cone. Then interlocked intermediate and casing borers are again fastened to head borer and reversibly rotated. After 2-3 turns casing borer is released and interlocked head and intermediate borers are removed from the casing borer. As casing borer presence in well becomes unnecessary casing borer is also withdrawn from well. Well drilling device comprises concentrically arranged head, intermediate and casing borers, which may be rigidly and flexibly aligned with each other.

EFFECT: increased well drilling efficiency, improved well quality and extended field of application.

7 cl, 4 dwg