STUDY OF UNIVERSAL COMBINED INHIBITOR FOR OIL AND GAS INDUSTRY

Abstract

Using the gravimetric method, the inhibitory efficiency of the combined inhibitor with respect to hydrogen sulfide and carbon dioxide corrosion of St3 steel in model-produced water MI was studied. Corrosion tests were carried out in 0.5 l sealed vessels on St3 samples of size 30×20×1. Gossypol resin + MARZA was used as a multifunctional combined inhibitor. Diesel fuel and kerosene were used as solvent. It has been established that the protective effect of using a multifunctional combined inhibitor in formation water with oil containing hydrogen sulphide and carbon dioxide using kerosene as a solvent ranges from 75 to 96 and for diesel as 80 to 100. The combined inhibitor allows to achieve in the MI medium containing hydrogen sulfide and carbon dioxide in the process of daily testing the corrosion rate of steel is about 0.04 g/ m2∙h only in a concentration of not less than 70 mg/l. However, with an increase in the duration of the test by an order of magnitude, a similar corrosion rate is observed already at an inhibitor concentration of 50 mg/l. The same is characteristic of carbon dioxide and hydrogen sulfide - carbon dioxide solutions. The bactericidal properties of the combined inhibitor with respect to two types of Desulfovibriodesulfuricans and Desulfomicrobium sulfate-reducing bacteria were studied. The effect of the inhibitor on the number of bacterial cells and the formation of hydrogen sulfide in Postgate nutrient medium “B” was evaluated. It has been shown that the combined inhibitor exhibits a bacteriostatic effect on to sulphate-reducing bacteria. It was revealed that the degree of suppression of the number of microorganisms Desulfovibriodesulfuricans at a concentration of the combined inhibitor 100.0 mg/l is higher than Desulfomicrobium. In the latter case, to achieve this effect, 120.0 mg/l concentration of the combined inhibitor is required. The studied combination inhibitor causes inhibition of hydrogen diffusion in steel St3 in the MI medium saturated with H2S and CO2 separately and together, and contributes to preserving the ductile properties of the steel St3 after exposure to solutions compared to non-inhibited media.