METHOD FOR DIRECTIONAL SIDE WINDOW CUTTING IN WELL CASING PIPE IN SINGLE DRILLING TOOL PASS WITH THE USE OF SCREW DOWNHOLE MOTOR AND SCREW DOWNHOLE MOTOR OUTPUT SHAFT STOPPING DEVICE FOR ABOVE METHOD REALIZATION Russian patent published in 2007 - IPC E21B29/06 

FIELD: well drilling equipment, particularly to cut side windows in casing pipes for following secondary bore drilling.

SUBSTANCE: method involves including whipstock device in bottomhole assembly, wherein upper whipstock device end is fastened to lower part of cutter-reamer assembly; connecting upper end of cutter-reamer assembly to shaft through extension member; rigidly connecting upper extension member end to screw downhole motor output shaft; fastening output shaft stopping device inside upper motor sub. Output shaft stopping device comprises hollow body provided with outer thread on upper body end part to connect thereof with upper sub of screw downhole motor. Upper bush part is fixed inside the body. Annular cavity communicated with annular receiving motor cavity through hollow lower body part is defined between body and bush. Bush has grooves formed in upper bush part in inner surface thereof. Created below the grooves are through channels. Lower bush part is provided wit inner bead. Bush-like piston is coaxially arranged inside bush so that it may slide in axial direction. The bush-like piston has grooves corresponding to that formed in inner bush surface. The bush-like piston is put on shaft by means of key. Lower part of shaft is conical and terminates in flat tongue. Conical part of stopping device shaft is retained in conical socket made in upper downhole motor rotor half-coupling. The flat tongue formed in shaft end is inserted in flat orifice of conical part. To stop output shaft the bush-like piston is installed in uppermost position. Then upper body end of stopping device is fastened to lower end of drilling string, bottomhole assembly is lowered in well within window cutting interval and azimuthal orientation is carried out from well head. After that whipstock device is installed in predetermined interval and released. Output motor shaft is freed by supplying pressurized working pressure from well head to displace bush-like piston in lowermost position along with simultaneous opening of through stopping device bush channels to provide working liquid flow into annular receiving chamber of screw downhole motor. Pressurized liquid supply is continued to rotate output downhole motor shaft and to provide directional window cutting.

EFFECT: decreased pipe wear, reduced material consumption and time.

4 cl, 3 dwg