Risk Assessment And Preventive Measures For Sour Gas Wells Atmospheric Environment Research

With the development of our country's economy, the natural gas demanding is increasing day by day. people pay more and more attention to the exploration of high sulfur content natural gas well represented by northeast areas in Si Chuan. In the exploration process of high sulfur gas well, because of the toxic and harmful substance such as hydrogen sulfide, once the blowout accident happens, it will cause serious effect to man's health and the environment. By doing research on the accident factors and risk, analyzing hydrogen sulfide leakage caused by accident, it's migration, transformation rule in the regional environment. Investigating the impaction on local people's health and the environment, according to the possible causes of the accident, putting forward effective preventive measures, it will have great significance on the exploration of high sulfur gas well.The paper studies on the environment risk caused by the blowout of sulfur gas well, based on the difference between sulfur gas well's drilling process and common gas well's drilling process, on the analysis of the blowout gas based on air dispersion model, through a gas diffusion numerical simulation method, mainly focusing on the risk of environment risk caused by the blowout of sulfur gas well, the main research contents include:(1) Take Si Chuan Wan Yuan's sulfur gas well A for example, doing risk material identification research in the exploration process of high sulfur gas well, research shows that the main risk materials includ natural gas, hydrogen sulfide and sulfur dioxide.(2) Doing quantitative risk evaluation, the results show that the personal risk maximum range is from 350 meters to 750 meters away from the well.(3) Using accident tree analysis the blowout and the out of control for blowout, results show that the main factors lead sulfur gas well A's blowout have:formation pressure forecast is flawed, formation pressure not timely, pump failure led to stall, homework stalled or artificial closing, and so on, the secondary factors have operators fluky psychology, break rules operation, drill encounter cave,and so on,but to the out of control for blowout, the most important factor is overflow evolution, so controlling the overflow evolution is the key step to prevent the out of control for blowout accident.(4) Doing safety mining of fuzzy comprehensive evaluation on sulfur gas well, considering factors of man's unsafe and things are unsafe. Results show the risk value is10.025, the rank of gas well mining accident is "low risk".(5) Based on gauss diffusion mode and the local environment characteristics of A well established gas sulfur blowout accident hydrogen sulfide leakage diffusion model, through numerical simulation, calculation in different environmental conditions, hydrogen sulfide in the atmosphere's space and time distribution characteristics, and it's landing concentration distribution rules, focusing on accident occurred after 5 minutes and 15 minutes within the area nearby hydrogen sulfur distribution characteristics and simulated mass casualties radius.(6) Discussing environmental risk prevention measures and emergency plan of sulfur gas well.