DEVICE FOR CABLE LOWERING INTO WELL Russian patent published in 2002 - IPC

FIELD: devices for investigation of oil wells with high wellhead pressure. SUBSTANCE: device is made in the form of volume hydraulic drive including hydraulic energy source in the form of high-pressure fluid taken from wellhead and also distributing shutoff-throttling device and outlet drive part in the form of hydraulic motor. Hydraulic motor is installed between lubricator and wellhead and consists of two pistons between which pulling split bushing for drawing cable through lubricator stuffing box is found. Pistons have hollow rods directed to opposite sides sealed together with pistons in airtight cylindrical body with formation of working cavities in it. Pistons are engageable with pulling split bushing installed in body for combined reciprocation. Pulling split bushing is made of soft flexible material. Opposite ends of pistons have additional rods, one of which embraces another rod and is conjugated and sealed with it over cylindrical surface and installed for mutual relative motion. External surface of embracing rod, internal surface of body and opposite ends of pistons form air cavity isolated from wellhead. Outer diameter of piston located on side of lubricator stuffing box is larger than outer diameter of piston located on side of wellhead. Wellhead cavity is communicated by one channel through shutoff-throttling device to working cavity located on side of wellhead, and by its other channel through distributing device to working cavity located on side of lubricator stuffing box. Working cavity is communicated through the same distributing device to drain. EFFECT: simplified design, reduced weight, labor input in manufacture and cost of device. 2 cl, 4 dwg