DEVICE FOR LIQUID INJECTION FROM WATER-BEARING WELL RESERVOIRS IN OIL-BEARING RESERVOIRS Russian patent published in 2007 - IPC E21B43/14 

FIELD: methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells, particularly method and device for cyclic liquid injection in oil-bearing reservoirs during reservoir flooding or reagent injection in the reservoirs.

SUBSTANCE: device comprises pump, main well, packer and pipe string with injection and suction valves arranged downstream and upstream of packer correspondingly. Main injection valve is located upstream of main suction one and has main annular channel located outside of main pipe string. The main annular channel communicates the main injection valve with well section located over packer. Main pipe string section located over injection valve has main cylinder with piston provided with rod and spring-loaded upwards. Main rod is arranged over main piston and passes from main cylinder in main pipe string in air-tight manner. Main cylinder interior section located upstream of main piston is communicated with main well interior. Device also has additional well, packer, pipe string with injection and suction valves, annular channel and piston provided with rod and spring-loaded in upward direction, which are connected with each other in the same way as main ones. Pump is of piston type and is communicated with main pipe string by one interior section defined by drive piston and with additional pipe string by another interior section. The working liquid is mineral oil or oil, which fills main and additional pipe string sections located over main and additional cylinders correspondingly, as well as piston pump interior. Working fluid is hermetically isolated from liquid to be injected from water-bearing reservoirs in oil-bearing ones, which prevents contact of working fluid with said liquid.

EFFECT: increased operational efficiency due to decreased energy inputs by device usage for two wells and elimination of frequent working liquid change, which decreased operational costs.

1 dwg