METHOD AND DEVICE FOR GENERATING WAVE FIELD AT INJECTOR BOTTOMHOLE WITH AUTOMATIC TUNING OF GENERATION CONSTANT FREQUENCY Russian patent published in 2015 - IPC E21B43/25 E21B28/00 B06B1/20 F15B21/12 

FIELD: oil and gas industry.

SUBSTANCE: group of inventions is related to the oil producing industry and intended for the improvement of oil recovery of productive formations. The method for generating a wave field at an injector bottomhole with the automatic tuning of a generation constant frequency lies in the generation of pressure fluctuations in a fluid flow pumped to a productive formation through tubing strings by its pumping through the flow-excited Helmholtz resonator (FEHR). At that the flow rate at a cross-section of an input nozzle and the distance between the input nozzle and a bushing with a discharge outlet is maintained. Moreover the flow rate at the cross-section of the input nozzle and the distance between the input nozzle and bushing with the discharge outlet is maintained due to the movement of the bushing with the discharge outlet, thus ensuring an increase of this distance at an increased flow rate and the above decreased distance at a reduced flow rate. The device used to this end consists of FEHR installed inside the tubing string; it represents a hollow cylindrical chamber with flat bottoms, wherein the input nozzle is placed in the front bottom and the bushing with the discharge outlet is placed in the rare bottom. At that the bushing with the discharge outlet is made movable and inside the tubing string behind FEHR there is a fixed hydraulic cylinder with a spring-supported piston connected by a rod to the fixed bushing with the discharge outlet. At that the cavity inside the hydraulic cylinder in front of the piston is communicated downstream to the annular space while the cavity behind the piston is connected to the inner volume of the tubing string.

EFFECT: improved efficiency of the stable frequency generation of pressure fluctuations at the bottomhole.

4 cl, 1 dwg