Corrosion behavior of P110 steel with hydrophilic amorphous SiO2 layer under different temperatures by water-alternating-supercritical CO2 injection: Experimental and molecular dynamics simulation

The role of a hydrophilic amorphous SiO 2 layer in the corrosion behavior of P110 steel at different temperatures during water-alternating-supercritical CO 2 (sCO 2 ) injection oil recovery was investigated. This study utilized a combination of experiments and molecular dynamics simulation. The results indicated that sCO 2 formed hydrogen bonds with hydroxyl groups on the surface of the hydrophilic amorphous SiO 2 layer, resulting in CO 2 enrichment at the deposited layer-P110 steel interface. The results further demonstrated that the hydrophilic amorphous SiO 2 layer, when subjected to different temperatures, played a crucial role in the CO 2 corrosion of P110 steel. In addition, the oxidation film formed by water injection at low temperatures was found to potentially inhibit CO 2 corrosion. However, with increasing temperature, localized oxygen absorption corrosion promoted subsequent CO 2 corrosion. At 333 K, with increased CO 2 diffusion capacity and enhanced CO 2 -P110 steel interaction energy, the FeCO 3 de-carbonation reaction transformed into creviced Fe 3 O 4 , which formed distinct internal and external corrosion layers on P110 steel. The crevice corrosion further exacerbated the degree of metal corrosion.