Corrosion and Fouling Behaviors on Modified Stainless Steel Surfaces in Simulated Oilfield Geothermal Water

Abstract

Corrosion and fouling are two critical issues that restrict the efficient utilization of geothermal water. The aim of this work is to find appropriate material surfaces of pipeline or heat exchanger utilized in Huabei oilfield geothermal water. In this work, three kinds of material surfaces (polished stainless steel (SS), stainless steel with TiO2 coating (SS-TiO2) and stainless steel with TiO2-FPS multilayer coatings (SS-TiO2-FPS)) were fabricated. These surfaces were characterized by surface free energy, surface morphology, X-ray diffraction and electrochemical performance. Immersion tests in the mixture of simulated geothermal water and crude oil at different oil/water ratios (Voil: Vwater = 0: 1, 1: 15, 1: 25, 1: 35, 1: 45 and 1: 55, respectively) were carried out to investigate corrosion and fouling behaviors on these surfaces. The influences of surface properties on corrosion and fouling behaviors were studied. The results indicated that SS-TiO2-FPS surface which had low surface free energy and hydrophobicity owned better corrosion resistance and antifouling performances compared with the other two surfaces. Polished SS surface presented better corrosion resistance but worse antifouling performance in simulated oilfield geothermal water compared with SS-TiO2 surface. As for the mixture of simulated oilfield geothermal water and crude oil, both oil scaling and water fouling adhered or deposited on the three kinds of surfaces. When the oil/water ratio (V/V) was 1: 25, the slowest average fouling rate was observed, and SS-TiO2-FPS surface also presented the minimum fouling adhesion compared with the other two kinds of surfaces. Hydrophobicity material surface may be the appropriate material surface being utilized in Huabei oilfield geothermal water.