OIL-WELL SUCKER-ROD PUMP Russian patent published in 2000 - IPC

FIELD: oil industry; natural gas and oil recovery. SUBSTANCE: inner ring groove made in cylinder communicates with drill string-borehole annulus. Groove is located at the level to provided its overlapping by plunger at working stroke and positioning above plunger when the latter is in BDC. Working space of pump cylinder at a definite level is provided with ring groove communicating with drill string-borehole annulus which increases service life of pump, provides draining of liquid at lifting of oil-well tubings and in case of plunger tear-off, ensures possibility of treatment of bottom hole area with chemical reagent, killing and washing of oil well directly without pulling sucker-rod strings, if necessary. EFFECT: increased capacity and quality of carried out operation, cutting down expenses. 2 dwg