Elemental Sulfur Deposition And Corrosion Mechanism Research On High Sour Gas Field Gathering And Transportation System

Puguang gas field in east Sichuan is the only successful mining in high sour gas field. As one of the most serious corrosion environment in high sour gas fields, composition of natural gas methane, hydrogen sulfide, carbon dioxide content are respectively70.05%～77.87%,11.11%～12.84%,8.61%～11.78. Elemental sulfur is mainly dissolved in H2S form polysulfide, elemental sulfur will deposition in the pipeline in the process of exploitation of natural gas from the bottom to the wellhead as the temperature and pressure decreasing, the deposited sulfur will cause the pipeline corrosion and clogging. Currently the elemental sulfur corrosion study is seldom at home, study the behavior of elemental sulfur corrosion on oil casing and the elemental sulfur corrosion mechanism are of particular importance for the guidance of high sour gas field corrosion protection.For the severe corrosion environment of elemental sulfur deposition in high sour gas field,study the pipeline corrosion conditions in the environment of elemental sulfur deposition in high sour gas field by coupon corrosion test in gas gathering pipeline of PuGuang gas field; Simulation may precipitate elemental sulfur in some working conditions in laboratory,study the influence of elemental sulfur content on corrosion,elemental sulfur corrosion mechanism and the effect of H2S different partial on elemental sulfur corrosion.On the conditions of add corrosion inhibitor, study the elemental sulphur influence on performance of corrosion inhibitors; by sulfur solvent and corrosion inhibitor compatiblity test.Through the above-mentioned aspects of the work,the conclusions are as following:The steel corrosion rate of gathering transport system is not high,corrosion status is primarily localized corrosion.The presence of elemental sulfur accelerated the corrosion rate of steel pieces,corrosion rate increased with the sulfur content increasing, and there is a concentration extremum.the corrosion rate of elemental sulfur on steel increased as H2S partial pressure increaseing.The elemental sulfur receives electronic in the recation,play a role of cathode polarization,accelerated the corrosion recation rate.Elemental sulfur deposition reduces the corrosion inhibitor corrosion inhibition performance. When sulfur deposition in large quantities,corrosion status is primarily general corrosion.The addition of sulfur sulvent makes the corrosion inhibition performance of corrosion inhibitor slightly lower, corrosion rate increases.