OIL-WELL SCREW PUMPING PLANT Russian patent published in 2000 - IPC

FIELD: oil producing industry. SUBSTANCE: proposed oil-well screw pumping plant had tubing string with single-screw pump mounted on lower end of tubing. Single-screw pump has screw connected with tubing string, and holder to be rigidly secured in casing pipe, after lowering the tubing string to required depth, by means of locking device coupled with holder. Locking device has three spring-loaded rollers moving along casing pipe line wall when tubing string is lowered, and providing preliminary fixing of device when tubing string is stopped. Locking device has also screw-and-wedge mechanism with retainers. When tubing string is subsequently rotated, torque is conveyed to mechanism with retainers under action of which retainers are pushed apart and finally fasten locking device with pump holder inside casing pipe. With pump secured in well, its screw continues rotating together with tubing string, thus delivering oil-containing liquid to surface. With tubing string rotated in opposite direction, screw-and- wedge mechanism releases retainers from contact with casing pipe which permits lifting of tubing string with pump to surface. EFFECT: enhanced reliability of fastening pump stationary member in well. 2 cl, 1 dwg