Nowadays, the problem of the biocorrosion of equipment placed inside oil wells due to the injection of unprepared water into oil reservoirs in order to increase the reservoir pressure is becoming more and more urgent. This has led to an adjustment of r water requirements for this purpose. According to the new standard that has been adopted in Russia, water for injection into reservoirs should contain no microorganisms.
Technologies which can be used for the sterilization of water are often costly and require the use of chemicals or membranes, which need to be periodically replaced. During the preparation of water for injection wells, the use of chemicals is very limited since aspects such as the deposition of reaction products inside the formation and environmental damage should be prevented.
A method for water sterilization based on the use of so-called sonoplasma discharge, an electrical discharge induced inside a cavitation zone, has been developed. In water flows, a cavitation zone may be created using hydrodynamic emitters. The initiation of such a discharge in water leads to a number of effects, including high local pressures and temperatures, UV radiation, and the formation of radicals.
Research on the effect of sonoplasma discharge on microorganisms was carried out. Sonoplasma discharge reduced E. coli by 98% (and by more than 99,99% after a second cycle) and Saccharomyces cerevisiae by 84%, showcasing the method's effectiveness.
The number of sonoplasma cycles required to reach the necessary suppression level is determined experimentally.
The proposed method is reagentless and wasteless. The equipment, which consists of a reactor equipped with electrodes and a hydrodynamic emitter, a pump, and a power source, is simple and can treat up to 20 m3/h., but it can be easily upscaled to 100 m3/h and more.
