Abstract
A research project was conducted by a joint research group for developing highly corrosion-resistant tubulars with thin protective layers on I.D. surface of high-strength low-alloy steel tubings. As a first step of the project, extensive experiments were performed to screen the proper coating materials and coating processes that give sufficient resistance to production environments and thus protect tubing from corrosion and cracking. The surface coatings were prepared on steel coupons and pipes by various processes such as PVD, CVD, plasma spraying, plasma transferred arc. The tested coatings included metallic, ceramics and polymeric materials. The screening tests consisted of corrosion tests simulating high temperature and high pressure sour environments and mechanical tests that simulated various types of mechanical damages during oil and gas production and work-over services. The candidate materials combined with the coating processes that were chosen on the basis of these tests were subjected to trial production of actual size of production tubings and the succeeding performance tests. The compilation of test results also give a data base of surface coatings to be applied in oil and gas production.
