METHOD OF AND DEVICE FOR COMPRESSING GAS OR GAS-LIQUID MIXTURE BY MEANS OF STRAIGHT-THROUGH PISTON Russian patent published in 2007 - IPC F04B1/00 

FIELD: drilling, completion and operation of wells.

SUBSTANCE: invention relate to injection of gases and gas-liquid mixture and it can be used in drilling with use of aerated drilling muds. Injection of gases and gas-liquid mixtures is done according to cycle in which duration of suction stroke dose not coincide with duration of delivery stroke and instantaneous speeds and accelerations of displacement of straight-through liquid piston differ at each stroke. Injection of liquid for replenishment of losses of liquid forced out into delivery line is done at beginning of delivery stroke at minimum delivery pressure. Method is implemented by means of pump consisting of at least two long-stroke hydraulically-driven positive displacement pumping sections. Each such section consists of working chamber with liquid supply channel, displacer and direction-action hydraulic drive hinge coupled with displacer. Each pumping section is provided with additional compression chamber with gas channel in upper part connected with external source of low-pressure gas or gas-liquid mixture and delivery main line connected with gas-liquid mixture consumer. Channel is closed by gas suction valve. Delivery main line is furnished with delivery valve. Each working chamber communicates through liquid supply channel with hydraulically driven pump (positive displacement meter) synchronized with said pumping station having working chamber. Chamber is furnished with suction and delivery liquid valves. Suction valve is installed in liquid supply line from external liquid source, and delivery valve is installed in delivery line connected with pumping section through liquid supply channel. Direct-action hydraulic cylinder is used for driving displacer. Hydraulic cylinder is installed on two hinged supports. Said supports preclude linear displacement independent from displacer, but permit rocking of hydraulic cylinder. Displacer is provided with additional support found inside working found inside working chamber of pumping section. Said support is coaxial with support found at inlet of displacement into working chamber and is arranged at end of working chamber opposite to point of inlet of displacer. Additional support is provided with sealing device. Displacer is made stepped (former by two coaxial cylindrical surfaces), smaller diameter of displacer is pointed to side opposite to inlet of displacer into working chamber. Smaller diameter is centered in above-indicated additional support, and, as a result, its "displacing" area acquires ring shape. Drive hydraulic cylinder is located inside displacer which is essentially hollow cylinder.

EFFECT: increased service life, improved manufacture and mounting.

3 cl, 1 dwg