Study of Suppression of Gas Bubbles Coalescence in the Liquid for Use in Technologies of Oil Production and Associated Gas Utilization

Abstract

Abstract The paper is devoted to the investigation of the stability of gas-liquid mixtures. Investigations of the suppression of the coalescence of gas bubbles in a liquid at various concentrations and composition of dissolved salts were carried out on a facility containing a laser diode with a telescopic system, a glass column, a bubbler, a gas supply system, a laser reception unit with a breaker, a lens and a photodiode, an oscillograph and a computer. The value of coalescence suppression was determined from the change in the transmittance of laser radiation through a column with bubbles in the liquid. In addition, bench tests were carried out on the characteristics of ejectors and a multistage centrifugal pump when creating and pumping gas-liquid mixtures using fresh water as a liquid, as well as aqueous solutions with various concentrations of NaCl. It has been experimentally determined that there are zones of rational salt concentrations and composition in which the coalescence of gas bubbles is suppressed due to the expression of repulsive forces between bubbles charged negatively in aqueous solutions of electrolytes. At smaller and higher concentrations coalescence suppression does not occur, and gas bubbles actively join with each other. The effect of cations and anions in aqueous solutions of various salts on the process of suppressing the coalescence of gas bubbles in a liquid is revealed. Investigations of the produced water from Samodurovskoye field showed that its composition helps to suppress coalescence of bubbles, but the addition of a certain amount of NaCl enhances the suppression of coalescence. When the water-gas mixture prepared by the ejector with using fresh water was pumped was pumped out on bench and the coalescence of gas bubbles was not maintained, the pressure developed by the multistage centrifugal pump decreased greatly with increasing gas content at the pump inlet. When using of NaCl aqueous solutions in the field of rational concentrations, a multistage centrifugal pump began to operate much better on a water-gas mixture. This was due to the suppression of the coalescence of gas bubbles in the liquid and the prevention of the formation of large gas caverns in the inter-blade channels of the pump. Field studies of the pump-ejecting system for SWAG injection on Samodurovskoye field were also carried out. The obtained results can be used for utilization of associated gas by water-gas injection, as well as in various oil production technologies, where gas-liquid mixtures move (completion, operation of wells, gathering oil, gas and water).