含硫气井的大气环境风险评价与防范措施研究

【作者】 陈安英；

【导师】 王兵；

【作者基本信息】 西南石油大学 ， 环境工程， 2011， 硕士

【摘要】 随着我国经济的发展,天然气的需求量日益增大,以川东北地区为代表的高含硫天然气田的开发越来越受到重视。由于以硫化氢为代表的有毒有害物质的存在,高含硫气井的开采过程中一旦发生井喷失控事故,将会对附近区域内人类身体健康与生态环境造成严重影响。论文对含硫气井的事故因素及风险评价进行了研究,分析事故泄露的硫化氢在区域环境中的迁移、转化规律,考察事故对于当地人群健康和环境的影响,针对事故发生的可能原因,提出有效的防范措施,对高含硫气田的开发具有重要意义。论文以含硫气井井喷事故所导致的环境风险开展研究,基于含硫气井钻井工艺流程与普通气井钻井工艺流程差别,在分析井喷气体大气扩散模式的基础上,通过气体扩散数值模拟,重点对含硫气井井喷事故的环境风险进行了研究,主要研究内容包括：(1)以四川省万源市含硫气井A井为研究对象开展高含硫气田开发过程中发生井喷事故的风险物质识别工作,研究表明主要风险物质有天然气、硫化氢及二氧化硫。(2)通过定量风险评价分析,结果表明个人风险最大的范围是距离井口350米—750米。(3)利用事故树分析法对井喷事故、井喷失控事故进行分析,结果表明含硫气井A井在开采过程中导致井喷事故发生的原因中最主要因素有地层压力预告不准、地层压力检测不及时、泵故障导致停转、作业停转或人为关停等,次要因素有操作人员的侥幸心理、违章操作、钻遇溶洞等；而对于井喷失控事故的发生,最主要因素是溢流演变,因此控制溢流演变是防止井喷失控事故发生的关键环节。(4)对含硫气井开采进行安全性的模糊综合评价,从人的不安全与物的不安全因素考虑,进行计算,结果表明风险值为10.025,气井开采事故的风险等级为“低风险”。(5)基于高斯扩散模式和当地环境特征建立含硫气井A井井喷事故造成的硫化氢的泄漏扩散模型,通过数值模拟,计算不同环境条件下,硫化氢在大气中的时空分布特点,及硫化氢落地浓度的分布规律,着重对事故发生后5分钟和15分钟内附近区域内硫化氢分布特点及群众伤亡半径进行模拟。(6)探讨高含硫气井环境风险防范措施及应急预案。更多还原

【Abstract】 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.更多还原