STUDYING THE INFLUENCE OF NEW COMBINED INHIBITORS ON THE PROCESSES OF CORROSION AND SALT DEPOSITION IN OIL-FIELD EQUIPMENT

Abstract

Aggressive salts contained in formation waters accelerate the processes of corrosion and salt deposition in oilfield equipment, which leads to unforeseen accidents, contamination of soil and groundwater with harmful substances, as a result of which the ecological balance of the environment is disrupted. Corrosion and scaling that occur during oil production create difficulties during the operation of wells, and, consequently, increase the cost of produced oil.This article covers the results of studies concerning two compositions developed from technical phosphatide - an emulsion obtained by hydration of vegetable oils, as well as sodium hexametaphosphate, ammophos and polypropylene glycol bottoms. When vegetable oils are treated with water and steam (hydration process), the phospholipids contained in the oils combine with water and are released in the form of precipitates called phosphatide emulsions. Such emulsions consist of 45–75 % water, and the rest is phospholipids in the vegetable oil sediment.Technical phosphatides are a group of esters that contain a phosphoric acid residue associated with an amino alcohol. They are natural surfactants and are non-toxic.Preliminary studies have shown that each of the chemical compounds included in the developed reagents has certain inhibitory properties, but when formulated, these compounds provide a synergistic effect.Based on the results of laboratory studies, it was found that at an optimal concentration of reagents of 200 mg/l, the developed compositions provide protection of equipment from corrosion destruction by 94–95 %, and from scaling by 87–88 %. The developed mixed-type inhibitors at optimal concentrations equally effectively inhibit both cathodic and anodic processes on the electrode.The use of these inhibitors leads to the prevention of steel corrosion in the two-phase oil-electrolyte system, as well as to a significant reduction in the rate of scaling.The proposed new compositions can be used in oil wells and in-field transport systems, as well as in reservoir pressure maintenance systems to protect against corrosion and scale deposits.Field tests of the corrosion inhibitor were carried out in deep pumping wells at the Bibieybatneft oil and gas production department. Tests have shown that as a result of using the inhibitor, the protective effect at a concentration of 200 mg/l was 89–90 %, and the effect of salt deposition was 70 %.