The inhibitory effect of selected reagents on carbon steel corrosion in formation water containing hydrogen sulfid

Abstract

For the first time, the impact of the composition of gossypol resin and IB-1 reagent, prepared in a 3:1 ratio and conventionally named HS-1, on the corrosion rate in hydrogen sulfide formation water has been investigated under laboratory conditions. Concentrations of 20, 40, 60, 80 mg/l of the new composition were used. During the experiments, a formation water sample taken from well No. 1082 of “Bibiheybatneft” OGPD, SOCAR, served as the electrochemical corrosion medium for the study. To conduct a comparative analysis, gossypol resin, IB-1 inhibitor, and HS-1 composition were used. Concentrations of 50, 100, 150, 200 mg/l of gossypol resin and 10, 15, 20, and 25 mg/l of IB-1 inhibitor were employed in the experiments. Numerous laboratory experiments revealed that the optimal consumption rate for the HS-1 inhibitor is 100 mg/l, for gossypol resin it is 200 mg/l, and for the IB-1 inhibitor it is 25 mg/l. These experiments were conducted under dynamic conditions over six hours. It was determined that the newly developed HS-1 composition offers superior protection in an aggressive medium containing hydrogen sulfide compared to its constituent components, gossypol resin, and IB-1 inhibitor. Specifically, as the concentration of gossypol resin in formation water increases from 50 to 200 mg/l, the corrosion protection effect ranges from 60–82%. When the concentration of IB-1 inhibitor varies between 10–25 mg/l in a hydrogen sulfide medium, the protection effect lies between 65-90%. In the aggressive medium of hydrogen sulfide formation water, increasing the concentration of the new HS-1 composition from 30–80 mg/l results in an enhancement of its electrochemical corrosion protection effect, ranging from 74–98%. Upon analyzing the results of numerous laboratory experiments, it was found that the optimal consumption rate of gossypol resin for corrosion protection in an aggressive medium with hydrogen sulfide is 200 mg/l, the consumption rate of IB-1 inhibitor is 25 mg/l, and for the HS-1 composition is 80 mg/l. The corrosion rates for gossypol resin in the concentrations of 50, 100, 150, 200 mg/l is 1.72, 1.38, 1.12, 0.78 g/m2 · h and retardation coefficient is 2.50, 3.10, 3.84, 5.51, respectively. Corrosion rate of IB-1 inhibitor concentration in the amount of 10, 15, 20, and 25 mg/l is 1.5, 1.12, 0.78, 0.43, and retardation coefficient is 2.86, 3.84, 5.51, 10.0, respectively. The corrosion rates for the new HS-1 composition at concentrations of 20, 40, 60, 80 mg/l is 1.12, 0.73, 0.34, 0.08, and the retardation coefficient is 3.84, 5.89, 12.64, 53.75, respectively. Comparing the corrosion rate values obtained for all three reagents with the corrosion rate for hydrogen sulphide formation water shows that new HS-1 composition has a higher effectiveness compared to its constituent components.