DEVICE FOR CUTTING PIPES IN WELL Russian patent published in 1998 - IPC

FIELD: oil and gas production industry. SUBSTANCE: this relates to devices intended for overhaul repair of wells by cutting off pump-and-compressor pipes in wells. Device has hollow body with radial passages and head-piece. Seated in radial passages are cutters. Cutting surface of cutters is reinforced with hard alloy. Also provided are springs which are interconnected with cutters. Three pistons are located in radial passages through 120 deg. spacings over perimeter of body. Cutters have their bases seated on protrusions inside body. Cutters have slot to receive locking strip which is secured on body same as springs. Springs are strip-like with bent end resting against cutter. After installing device in pump-and-compressor pipes at required depth, they are preliminarily tensioned by force which exceeds their own weight. At injecting liquid into device at flow rate ensuring design pressure obtained due to head-piece, pistons are brought to centralize device, and during rotation of device cutters are cutting off pump-and-compressor pipes. Completion of cutting process is determined by reduced axial force at well head. Prior to extracting device, well is washed by reverse circulation. EFFECT: higher efficiency. 5 dwg