川西气田高含硫气藏环保测试技术应用及建议

Application and Suggestion of Environmental Protection Testing Technology for High Sulfur Gas Reservoir in Chuanxi Gas Field

川西气田地处川西较发达地区,气田主力层位雷口坡组为海相气层,硫化氢含量平均5.15%,属于高含硫气藏。在实施增产措施后的排液阶段,受残酸及硫化氢影响,出现异味扩散强烈,造成周边环境问题;同时返排液含硫化氢较高,运输过程中极易溢出,形成硫化氢中毒隐患。一般现场采用的放喷池预先加入氢氧化钠溶液进行中和的方式,已不再能适应现场实际状况。为进一步消除环境及安全隐患,通过对现场不断改进实施的“流程伴注除硫剂、除味剂 + 放喷口喷淋碱液 + 放喷口点火”、“在线实时除硫 + 放喷口喷淋 + 放喷口喷淋清水 + 放喷口点火”多种工艺应用效果对比,最终选择“酸性条件实时除硫工艺 + 放喷口点火”工艺,同时摸索出除硫剂及碱液加注参数,初步形成一套川西气田高含硫气层环保测试技术。目前现场已基本排除异味影响,返排液处理指标达到PH值7~9,H2S浓度 ≤ 5 ppm,满足直接入罐进行拉运要求。

Western Sichuan gas field is located in the developed area of western Sichuan and the main gas layer is characterized by high sulfur content, hydrogen sulfide content averaged 5.15%. In the drainage stage after the implementation of stimulation measures, influenced by residual acid and hydrogen sulfide, strong odor diffusion occurred, causing environmental problems in the surrounding area. At the same time, the flowback liquid contains high hydrogen sulfide, which is easy to overflow during transportation, forming hydrogen sulfide poisoning hidden danger. Generally, the neutralization method of adding sodium hydroxide solution in the blowpit can no longer adapt to the actual situation on site. To further eliminate the environmental and safety hidden danger, through continuous improvement on the spot on the implementation of “process with sulphur removal agent, in addition to flavor agent + injection with spray nozzle spray fire”, “online real time in addition to sulfur + feed nozzle spray + nozzle spray fire” two kinds of technology application effect of contrast, finally choose “acid condition real-time desulphuration process + put nozzle ignition” process, at the same time for sulphur removal agent and alkali liquor filling parameters, a set of environmental protection testing technology for high sulfur gas layer in west Sichuan gas field has been preliminarily formed. At present, the field has basically eliminated the influence of peculiar smell, the treatment index of flowback liquid reaches the PH value of 7~9, and the H2S concentration is less than or equal to 5 ppm, which can meet the requirements of directly into the tank for transportation.