广元至阆中段浅层天然气发育区工程地质选线研究-《高速铁路技术》

文章信息/Info

Title:: Study on Engineering Geological Route Selection for Shallow Natural Gas Development Zone in Guangyuan-Langzhong Section of Lanzhou-Chongqing Railway

Author(s):: WANG Chonggen; China Railway Eryuan Engineering Group Co., Ltd., Chengdu 610031, China

Keywords:: geological route selection|red bed|shallow natural gas|oil and gas structure|disseminated area

摘要:: 兰渝铁路广元至阆中段，长约90 km，是国内第一条主要以隧道工程长距离穿越红层地区浅层天然气发育区及其浸染区的铁路，浅层天然气影响并控制线路走向，选择适宜方案通过，难度极大。文章通过分析区域内含油气构造、油气田相关资料，采用地质调绘、钻孔、现场测试、室内检测、岩石试验等手段，对区域浅层天然气发育进行研究，研究表明：（1）浅层天然气发育程度与油气田及含油气构造相对位置有关，距离越远，影响越小；还与岩性组合、构造情况相关，岩石孔隙比大、地表穹隆构造（背斜）、断裂构造发育区域，浅层天然气发育程度相应高；（2）分析区域内浅层天然气对各线路方案中隧道工程的影响，进行线路方案比选，结果表明中线方案浅层天然气风险最小；（3）本区域浅层天然气发育特征规律、选线原则亦值得在四川盆地浅层天然气发育区工程设置时推广。

Abstract:: Guangyuan-Lanzhou section of Chongqing-Lanzhou railway, which is about 90 km, is the first railway in China passing through shallow natural gas development zone in the red layer area and its dipping area. The railway line selection is very difficult because the shallow natural gas influences and controls the alignment. Through analyses on oil and gas structure, oil and gas field data, the shallow gas development is studied by adopting the means of geological annotation, borehole, on-site test, indoor detection and rock test. The research shows:(1) The development degree of shallow natural gas is related to the relative position of oil and gas fields and hydrocarbon-bearing structures, the farther the distance, the smaller the impact. It is also related to lithologic assemblages and tectonic conditions. The development of shallow natural gas is correspondingly high in areas with large pore ratio of rocks, surface dome structure (anticline) and fault structure; (2) The influence of shallow natural gas on tunnel engineering in each line scheme is analyzed, and the line scheme comparison is made. The result shows that the risk of shallow natural gas in the middle line scheme is the smallest; (3) The characteristics of shallow gas development in this region are also worth popularizing in the engineering setting of shallow gas development areas in Sichuan Basin.