Acoustic stimulation of oil production by a downhole emitter based on a jet-driven Helmholtz oscillator.

Development of oil fields by the most common waterflooding method leads to an increase in the water cut of the recoverable oil and a low oil recovery factor (for Russia, about 30–40%). The solution to this actual problem seems to be in the combination of the applied waterflooding method with the elastic wave action. This paper presents the results of the use of acoustic stimulation as an unconventional but promising approach to enhanced oil recovery. This study developed a borehole emitter and acoustic action technology to stimulate oil production. In this borehole hydrodynamic emitter, based on the jet-driven Helmholtz oscillator, the generation of intense acoustic pressure oscillations occurs due to the energy of the fluid flow injected into the formation. Bench tests made it possible to determine the operating parameters and frequency characteristics of the device. Field tests were carried out in Russia at an oil field that is in a late stage of development. An increase in oil production has been achieved; the water cut of the produced oil has been reduced; the injectivity of the injection well has been increased due to the restoration of the filtration properties of the bottom-hole zone. Thus, the developed technical devices, operating at kilohertz frequencies, and the production technology can be used as a promising method for stimulating oil flow and enhancing oil recovery. The advantages of the proposed acoustic treatment are their relatively low cost, simplicity of device design, high efficiency, and environmental friendliness, as well as the possibility of combining this technology with almost all traditional methods of enhanced oil recovery. • Borehole emitter and acoustic technology to stimulate oil production are developed. • Sound oscillations increase the well injectivity with contaminated bottom-hole zone. • Average increase in the oil production rate is 1.68 tons per day (11.8%). • The advantages - small-size equipment, ecologically safe and low operating costs. [ABSTRACT FROM AUTHOR]