| With the continuous development of petroleum exploration and development,the service conditions of tubing in injection Wells are becoming more and more severe.The complex alternating stress,the increase of water content and the coexistence of various corrosive media lead to the increasingly serious tubing failure problem,which puts forward higher quality requirements for epoxy coatings commonly used at present.Due to its large specific area,chemical stability and mechanical properties,graphene added to epoxy coating can improve the protection performance of epoxy coating under the condition of water injection well.This paper aims to promote the large-scale application of graphene epoxy coating on tubing.By selecting different specific surface areas of reduced graphene oxide(RGO),changing the amount of RGO added to epoxy resin,and comparing and analyzing various properties of RGO epoxy composite coating with different specific surface areas and content.An economical and highly performance composite coating for oil tubing with RGO additive filler was selected to prepare industrial composite coating,and its performance after service in water injection Wells was analyzed.The study on the strength and toughness of RGO epoxy resin composite coating shows that excessive RGO will reduce the tensile strength of epoxy resin coating.By contrast,the maximum tensile strength of the 1#graphene epoxy resin coating with smaller surface area was increased by 50%,and that of the 2# graphene epoxy resin coating with larger surface area was increased by 122%.However,the fracture speed was significantly faster during the tensile process,indicating that the epoxy resin aging and crosslinking density increased at 80℃corrosion soaking.Resulting in increased hardness,toughness significantly decreased.The corrosion resistance of RGO epoxy composite coating showed that the impedance of 1#RGO was 3 times lower than that of 2#graphene epoxy coating with 0.3wt%,but the impedance reduction rate of 1#coating in corrosive medium was much lower than that of 2#coating,and the price of 1#graphene was 85%lower than that of 2#graphene.More suitable for industrial RGO epoxy resin composite coating scale application.The 300-day service test results of industrial coating show that RGO epoxy composite coating still has a certain protection ability after 300 days of service in the field water flooding condition,and the low-frequency impedance can reach 9.03×10~8Ω·cm~2 after service.However,with the increase of well depth,the service temperature increases,and the coating shielding performance decreases. |
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