龙泉山瓦斯赋存控制因素及综合评价方法

Controlling Factors of Gas Occurrence and Comprehensive Evaluation Method in the Longquan Mountains

为研究龙泉山瓦斯赋存控制要素,降低工程建设风险,结合龙泉山瓦斯事故及地质资料分析,该区瓦斯是来源于须家河组生烃层的天然气,经断层-裂缝运移至背斜或构造高点的侏罗系砂体中,并在浅部以“气包状”聚集。为定量评价瓦斯危害,基于气测录井、气体浓度检测、瓦斯压力测试结果,提出了浅层天然气类瓦斯溢出量计算公式,并建立其涌出量与溢出量的相关关系,结果表明,龙泉山隧道瓦斯气体含量最高达150000ppm,一氧化碳含量最高为99ppm,瓦斯溢出量为141141 m^3,瓦斯涌出量为2.69m^3/min,达到了高瓦斯隧道判别标准。研究结果对成都市城市工程建设瓦斯风险防控具有一定的指导意义。

Available information indicates that gas in the Longquan Mountains is derived from the source rock of the Triassic Xujiahe Formation,migrates along faults and fissures and occurs in the Jurassic sandstone at high point of anticline or structure.The calculation formula of overflow quantity of shallow gas is put forward on the basis of logging data,gas concentration and pressure measurement.The calculation indicates that gas content in the Longquanshan Tunnel is up to 150,000 ppm with CO of 99 ppm and gas emission of 2.69m3/min which has reached the criterion of high gas tunnel.The research results are of great importance to the prevention and control of gas risk in urban construction of Chengdu.