The Risk Prediction And Control Of H₂S Leak In Gas Station Over Complex Terrains Conditions

Natural gas play an important and more apparent role in people’s lives as a clean energy, and the demand also showed a rising trend, more and more sour gas wells put in mining in order to meet the demand for natural gas. Because of the "three highs" (high levels of toxic gas, high capacity, high pressure) feature of sour gas wells, it will affect a wide area, make a huge toxicity and have a serious impact on the surrounding residents when the sour gas leaked. The spread of leak H2S gas is complex, so it is difficult to do emergency rescue work especially in complex terrain condition. Gas gathering station has a key position in the gathering system, the piping and equipment are numerous and concentrated in the gas station, so it has an important practical significance for security and green operations of high sulfur gas gathering station to predict and control the risk of H2S leakage over complex terrain conditions.By using the integrated risk identification methods that combined the checklist method, flow diagram method and Delphic method (expert survey method), the author found that the hydrogen sulfide leakage risk factors in high sulfur gas gathering station are internal corrosion, external corrosion, dynamic seal point, quiet seal point, personnel operating and the overall layout; the leakage risk sources are wellhead separators, metering separator and production pipes.:By using HYSPLIT software and combining with local meteorological, atmospheric and terrain conditions to predict regular pattern of H2S leakage in a gas gathering station in Sichuan for the study, the result shows that the diffusion direction of H2S was significantly associated with the wind direction, the maximum concentration of hydrogen sulfide diffusion was in calm wind conditions, the maximum scope of hydrogen sulfide was a radius of 1.16km by gas gathering station.Combining with the consequences of risk predict, the author proposed the source control program that have three kinds of controls from the site selection of gas gathering stations, material selection of pipelines and non-pipeline equipment and construction; a process control program that strengthening equipment and personnel management targeted, establishing warning systems was also proposed; and proposed an end control program that establishing emergency rescue system based on the influence of leakage.