Acid Gas Corrosion Inhibitor Performance Influencing Factors Evaluation And Field Application

With the development of the oil and gas exploration,more highly acid gas field are found,such as Sichuan Province,Tarim and the Bohai.Corrosion of the acid gas has became the biggest problem which restricted the safety and the efficient production of gas.In this article on the background of Tarim-1 gas field,the testing liquor is simulation gas field formation water,corrosion performance was comprehensive evaluate.First,the operation flow of oxygen corrosion test has been improved.In this process,using high-purity Nitrogen with 100mL/min velocity for 18 hours to remove the oxygen of the test solution.Then suction vacuum reactor.This is a standardized oxygen removal process.Re-tested demonstrate good reproducibility.This process can make sure the corrosive test and inhibitor evaluation more accurately and reliable.Evaluated the properties of inhibitor by weight loss method and electrochemistry corrosion method in laboratory.The mail component of inhibitor are imidazoline,organic amine,glacial acetic acid,oleic acid.The experiment showed the corrosion rate of N80 steel is 0.0362mm/a,the inhibition of corrosion rate is 81.14% when N80 steel is exposed in 80℃ environment,pressure of CO₂ is 0.5MPa,the amount of CGW9107 D is 200 ppm.And the corrosion rate of L360 steel is 0.0648mm/a when it exposed in 60℃ environment,pressure of CO₂ is 0.48 MPa,pressure of H₂ S is 0.21 MPa,rotational speed is 400r/min,the amount of inhibitor 8-1R is 100 ppm.the Corrosion rate is obtained with salinity,temperature and rotation speed,and corruption is easier to happen in acid conditions.As an antifreeze,methanol is used to prevent the generate of gas hydrate.By an experiment of the pipeline which involved methanol,and dissolution oxygen are found in methanol,and the methanol will increase the content of oxygen and increase the corrosive rate.What’s more,methanol affected the film forming of the anti-corrosive agents,reduce the inhibition corrosion effect.A new inhibitor named 8-1R has a good physical properties,corrosive examination has been made in many pipeline,experiment in Tarim-1 shows its good corrosion control abilities.