ПРЕДУПРЕЖДЕНИЕ НАКОПЛЕНИЯ ЭЛЕКТРОСТАТИЧЕСКОГО ЗАРЯДА НА ПОВЕРХНОСТИ НЕФТЕПРОМЫСЛОВОГО ОБОРУДОВАНИЯ

Abstract

Background Currently, the majority of Russian oil fields use reservoir pressure maintenance systems (RPM). Their use helps to increase the concentration of the aqueous phase in the oil-water emulsion. The presence of water in oil emulsion intensifies local corrosion processes. Due to corrosion local areas with a pronounced differentiation of the electrode potential are formed. The bias of the electrode potential on the surface contributes to the appearance of corrosion pits, which in future may lead to through destruction. While oil-water emulsion moves over the metal and the lined pipeline an electrostatic charge accumulates on their surface and provokes intensification of electrochemical corrosion. Moreover, the presence of static electricity on the surface of the oil-field equipment is undesirable, as it may contribute to the emergence of sparks that can cause an explosion and fire of accompanying petroleum gas. Therefore, the exclusion of electrostatic charge accumulation on the metal surface of the oilfield equipment will significantly reduce the number of accidents, increase the term of its operation and improve the reliability and quality of service in the oil fields. Aims and Objectives Studying the phenomenon of accumulation of electrostatic charge on the metal surface of a pipeline makes possible to assess the probability of bias of the electrode potential and to prevent electrochemical corrosion. To eliminate the accumulation of electrostatic charge on the metal surface it is necessary to localize it on special devices and discharge to an external earth electrode. Methods Standard methods for measuring the electro-chemical variables - pH, redox potential of the medium, the potential values on the surface of a metal pipe - were used in research. Specially prepared model of oil-water emulsion was used for laboratory and bench tests. Results Studies have shown that the effective elimination of electrostatic charge accumulation on a metal surface requires special devices - neutralizers that localize this charge on themselves and discharge it to an external earth electrode. Application of the developed devices allows the electrode potential of the metal surface biased by 0.25-0.30 V in relation to the natural potential. Three kinds of the neutralizer were designed during the research. Specifically designed carbon-graphite anode with coke-pitch binder was used as an earth electrode. Pilot tests of the neutralizers have shown that their use 3 times reduces the corrosion rate of steel oilfield equipment in the aqueous phase.