ANALYTICAL INVESTIGATION OF THE PROBLEMS OF SALTING AND CORROSION IN OIL AND GAS COMPLEX

Abstract

One of the problems that cause difficulties in the operation of oilfield equipment and pipeline communications of wells during oil production is asphalt-tar and paraffin (AGPCH). Accumulation of AGPCH in the flow of oilfield equipment reduces the productivity of the system and the coefficient of useful operation of pumping units, as well as shortens the maintenance period. Reduction of pressure at the bottom of the well and, in this regard, violation of thermodynamic balance of the gas-fluid system, intensive gas separation, temperature drop in the reservoir and well body, change of speed of movement of the gas-liquid system and its individual components, composition of hydrocarbons in each phase of the mixture, ratio of the volume of phases and the state of the surface of pipelines. During oil and gas extraction, deposits of inorganic salts are also formed on the inner walls of mining pipelines and equipment. The deposition of salts on the surface of the working bodies of pumps increases their frictionality, causing the dispersion of shafts, workbenches of centrifugal pumps. In oil fields, the deposition of calcium sulfate, calcium and magnesium carbonate and sodium chloride is also characteristic. In aqueous solutions, H2S significantly enhances the penetration of hydrogen into steel compared to general corrosion. The catalytic effect of hydrogen sulfide on hydrogen fragility of metals is given. The presence of CO2 in the liquid and gas produced during oil and gas extraction also speeds up the corrosion process. Therefore, the essence of the corrosion process in the presence of CO2 is shown. Since CO2 is soluble in water and forms weak carbonic acid H2CO3, this acid dissociates into hydrocarbonate and carbonate ions. Formation of CaCO3 in the water phase of oil fields products goes in the presence of hydrocarbonate ions, since the concentration of carbonate ions in them is close to zero. Since one of the products of this reaction is carbonic acid, the deposition of CaCO3 depends on the pressure. Most organic compounds have the ability to slow down corrosion of metals. Organic compounds are inhibitors of mixed action, in other words, they affect the speed of both cathodic and anode processes. Investigation of corrosion sensitivity conditions and mechanism of their formation of equipment and pipe and communication lines in the oil and gas industry makes it possible to develop more effective inhibitors. Keywords: oil emulsion, salting, corrosion, water phase, inhibitory, hydrogen fragility.