Сorrosion monitoring system for oil extraction equipment
Corrosion is the main cause of most accidents on pipelines, casing and tubing, and reduces the life of pumping equipment at oil fields. The effect of the influence of crude oil on the corrosion processes is still poorly understood. A simple mechanistic model that takes into account the cumulative effects of changes in corrosion inhibition and wetting due to adsorption of polar molecules on the surface of steel, has not been studied in detail, although the inhibitory effect is dominant in the oil-water emulsion. High specific accidents oil recovery pipes and low pressure water lines, because corrosion associated with low-velocity flow environments, because in these conditions, there is a bundle-water emulsions to form an aqueous sublayer (in the case of oil-gathering system) and the removal of solids from their subsequent deposition on the walls of the pipes. Is intensified due to corrosion appearance and action macro galvanic couples "metal pipe - deposits". With increasing water content, the presence of CO2 (and, therefore, HCO3-) and SRB create favorable conditions for the growth of pipelines for oilfield accident. Internal corrosion of mild steel in the presence of CO2 and H2S is a serious problem for the oil and gas industry. Although interaction of low-carbon steels with H2S published in the press various authors, understanding the effect of CO2 and H2S corrosion is still limited because the nature of their interaction on the surface of carbon steel is quite complex.When hydrogen sulfide is present and dominant in relation to the concentration of CO2, iron sulfide film (FeS) prevents the formation of carbonate scale (FeCO3). This is of interest because the film of iron sulfide easily removed from the tube wall than iron carbonate. In turbulent conditions, the removal of the protective film of iron sulfide would increase the corrosion rate. Sources of hydrogen sulfide in the formation water may be as mercaptans, H2S which form when heated and functioning microflora (SRB).
The process of hydrogen sulfide corrosion of carbon steel in aqueous electrolytes have a stimulating effect not only H2S, but corrosion products - iron sulfide (FeS).
Iron sulfide with respect to iron and steel is an efficient cathode. If dissolved H2S and CO2 corrosion as factors dominate the concentration of chloride in the oil reservoir water, it leads to increased corrosion activity, and increasing formation water salinity affects the solubility of H2S and CO2 and decrease in the concentration of salts.The kinetics of the formation of deposits in the system is quite complicated CO2/H2S and is still not well understood. Deposits on the surface, in these conditions, depend only on the acidity environment and dissolution of carbonates and sulfides iron, but the kinetics of the mechanisms of the process. The influence of suspended particles on the corrosion process due that the motion in the fluid, damaged protective films and coatings on the walls of pipes, in addition to the metal surface often form loose deposits Giving no protective effect, and do not block access depolarisers the metal surface. When exposed to the aerated and anaerobic conditions on the metal surface, a buildup of corrosion and mechanical impurities, formation and functioning effectively acting pairs of differential aeration, which also stimulates localized corrosion of ferrous metals. The presence of cavitation of the particles reduces the concentration of corrosion inhibitors and leads to a reduction of the protective effect. In hydrochloric environments inhibitors slows the flow of the two partial reactions: cathodic hydrogen and anodic dissolution of the metal, but with increasing HCl leads to a reduction of the protective effect.
The concentration of asphaltenes and resins affects the formation of paraffin. As part of both components are being natural surfactants - active substances which in small quantities to form the substrate on the walls of pipes and equipment that contribute to the formation of deposits. An increase in their concentration in the liquid part of the products well they prevent the formation of deposits of cavitation particles.
Company "Korsystem" pays great attention to the study of questions as to study the corrosion process under the influence of corrosive elements and deposits formed in the process of oil production. Today has occumulated a large amount of data obtained during the implementation of services for corrosion protection of oil field equipment.
The company "Korsystem" conducts research work on the development of new techniques and methods to study corrosion processes in real time.