METHOD AND DEVICE WITH RING FOR GENERATION OF PRESSURE WAVES AT BOTTOM OF WELL Russian patent published in 2016 - IPC E21B43/25 E21B28/00 E21B43/16 F15B21/12 

FIELD: oil and gas industry.

SUBSTANCE: generation method of pressure waves at the bottom of the well, at which a Helmholz spray oscillator (HSO) is installed on the lower end of a channel of a tubing string. HSO represents a hollow rotation body and consists of the following: a cylindrical chamber with two parallel bottoms; an inlet nozzle located in the centre of one bottom; and an outlet hole with a sharp edge, which is located coaxially with the inlet nozzle in the centre of the other bottom; in which the inlet nozzle is connected to the channel of the tubing string, and the outlet hole is directed to annular space of the well. Liquid is supplied through the inlet nozzle to the cylindrical chamber; with that, a liquid jet with disturbed periphery is formed in space between the bottoms. The liquid jet is supplied to the outlet hole. Therefore, primary pressure fluctuations are generated in the zone of the sharp edge. Primary pressure fluctuations are amplified in the cylindrical chamber, the natural frequency of which is tuned with resonance to frequency of primary pressure fluctuations, and pressure waves are formed after the outlet hole in annular space of the well. A ring with a sharp inner inlet edge is installed inside the cylindrical chamber between the bottoms. The liquid jet is supplied to the outlet hole so that the jet in space between the inlet nozzle and the outlet hole can flow through the ring and touch the sharp inner inlet edge of the ring with its disturbed periphery, and therefore, primary local pressure fluctuations are formed in the ring zone. Natural frequency of the cylindrical chamber is tuned with resonance to the main frequency of primary pressure fluctuations.

EFFECT: improving efficiency of pressure wave formation in annular space of the well.

4 cl, 1 dwg