Corrosion And Anti-Corrosion Techniques For Air Injection EOR Process

Air injection is an effective method for EOR,receiving more and more attention in recent years. At present, there are several dozens of oil fields are using this technology in the world. The Field application of ZhongYuan oil field and BaiSe Oil Filed in China has indicated that air injection and air-foam injection has high flooding efficiency and can be of a comparatively economic EOR technique in comparison of N2 injection. But the corrosion of pipe string is more serious during the air injection process. There are two main corrosions in the process, that are oxygen corrosion in injection wells and carbon dioxide corrosion in production wells. They give rise to the more serious corrosion on steel tube causing general corrosion and local corrosion, and even cause oil tube and casing corruption crack, thus it can shorten production life of oil well with huge economic loss. The subject which mainly discussed the oxygen corrosion of injection wells and carbon dioxide corrosion of production wells carried out the following studies:In the corrosion working conditions of production wells, the paper studies the inhibitory performance of the four carbon dioxide corrosion inhibitors by weight-loss experiment. According to a variety of working conditions, it reveals the law of concentration, temperature, flow rate and time on the inhibitory performance, and studies the synergistic inhibitive effect of corrosion inhibitor.According to the corrosion environment of injection well, Air corrosion inhibitor and air-foam corrosion inhibitor are selected by weight-loss experiment. Besides, it also studies the influence law of corrosion inhibitor and air foam, as well as oxygen on carbon dioxide corrosion.According to the process of air injection, the article proposes some formations which includes pre-film formation and normal injection formation in air injection well and production well. The flow chart for the implantation technique for the injection well and production well is designed and described on basis of methods injected and working site, besides, it launches three methods of corrosion monitoring. Finally, the paper makes some suggestions about the implantation technique of corrosion inhibitor.Finally, it gives a synthetic measure to control the corrosion on the basis of oil field. Therefore, it could reduce the corrosion rate, prolong pipe string's life and make sure that the process will be better.