Корозія бетону надводної частини нафтопастки в водному господарстві нафтовидобувного підприємства

Abstract

The purpose of the work is to identify the type and kinetic indicators of concrete corrosion of the surface part of the oil trap in the water management of oil-and-gas facilities. Biogenic sulfuric acid concrete corrosion is a constant risk for water management facilities, in which hydrogen sulfide and its derivatives are present in the operating environment. Based on the analysis of the cycle of the oil production enterprise, the above processes are inherent in the water management of oil-and-gas facilities. The presence of hydrogen sulfide in water operating environments indicates a very high probability of the development of biogenic sulfuric acid aggression in the above-water moistened part of the structure - the influence of sulfuric acid produced by thion bacteria. An attractive environment for the accumulation of hydrogen sulfide by microbiological sulfate reduction is reservoir water at oil production sites, especially at water management sites where long-term sedimentation occurs. About 80% of losses from corrosion of oil industry equipment are associated with the activity of sulfate-reducing bacteria. In the experimental studies, concrete samples were studied, which were taken from the upper surface of the oil traps at the studied oil production facility located in the Dnipro-Donetsk depression. The results of a chemical study of concrete samples (decrease in pH, accumulation of sulfur compounds, and leaching of calcium compounds) indicated that the concrete is affected by biogenic sulfuric acid aggression. The experimentally determined dynamics of calcium compounds in the studied concrete samples indicated its leaching by aggressive sulfuric acid: the lower the pH of concrete, the lower the concentration of total calcium and the higher the concentration of mobile calcium. Based on data determined using a concrete corrosionmeter, the rate of microbiological corrosion of concrete was calculated - up to 0.08 mm/year, and the depth of diffusion of biogenic acids - up to 1.9 mm. The calculated average annual concentration of hydrogen sulfide in the atmosphere affecting concrete was 3.4 - 5.4 mg/m3, which exceeds the MPC of the working zone in the oil and gas industry.