Study And Evaluation Of The Inhibitor Used For Gas Wells And Surface Gathering Of Natural Gas Field Containing H₂S

Moore content of H₂S in Puguang gas field is about 14.61% in average.We can say it's a gas field including high content H₂S.Besides,it has high content of CO₂ which reaches to 9.21%.Because of the hypertoxicity of H₂S and highly corrosive of H₂S / CO₂,the gas field's ground-gathering system is confronting with the problems of extrusive safety and crossing control.According to the corrosion appearing in the course of exploiting,gathering and transfering,we did some experiments in the lab bonding with the data from the job site.we do further research to evaluation methodology of the inhibitor and its application in the gas well including high content H₂S as well as ground gathering and transportation equipment,so we can make the problem of corrosion easily controlled.After turning over the books and field research,we elaborate the corrosion mechanism and affecting factors of H₂S and CO₂.Then we analyze the working mechanism of inhibitor from the aspect of electrochemistry and physical chemistry.According to the data collected,we do the evaluation about the preliminary screening,simulation environment and performance to the better inhibitor samples from the domestic oil and gas fields,universities and colleges,research institutes aiming at different ambient conditions like the gas well and surface gathering,According to the result of the inhibitor used in the surface gathering,we find a good inhibitor combination which use OS-10 as the pre-film inhibitor and WS-10 as the continuously injected inhibitor for the surface gathering,its corrosion rate is only 0.043mm/a,inhibition rate reached 94.6%,and its working mechanism is perfillmimg inhibitor Protective film on metal surface to impede the transfer of charge or substance those are related with the corrosion reaction and imidazoline in great degree inhibit the corrosion process at the anode;According to the laboratory result of the inhibitor used for gas well,we find GWS-1 and GWS-2 can form a more compact film at high temperatures,inhibition rate both reached more than 97%,inhibition effect is good,their working mechanism are quaternary ammonium ion are adsorbed on the negatively charged metal surfaces and forms a compact film that can prevent metal contacting with the corrosive medium,and the N on quinoline can coordinate with metal surface atoms and form a dense adsorption film on the metal surface,then achieve a better inhibition effect.At last,we produce a preliminary plan about filling-up and perfermance of the surface gathering inhibitor and gas field inhibitor according to the actual working conditions of gas field containing H₂S and CO₂.