陆相页岩气资源评价初探:以延长直罗—下寺湾区中生界长7段为例

A preliminary discussion on evaluation of continental shale gas resources:A case study of Chang 7 of Mesozoic Yanchang Formation in Zhiluo-Xiasiwan area of Yanchang

页岩气是一类非常规天然气聚集类型,在中国找页岩气的实践还处于初期阶段,如何合理评价其资源量目前还没有成熟的方法,尤其针对陆相页岩气评价更缺乏借鉴和参考。文中在分析海相、陆相页岩的差异和特点的基础上,明确陆相页岩资源评价的条件和标准。针对延长探区中生界三叠系延长组页岩开展研究,在样品测试、含气量初评的基础上,对陆相页岩气的资源进行初步评价。对不同勘探程度和地质条件采用不同的资源评价方法,综合不同方法获得的结果认为,延长直罗—下寺湾区中生界陆相页岩气资源量达到(626.4～6 037.2)×108 m3,具有很好的勘探开发价值。

Shale gas is a kind of unconventional natural gas accumulation types;its practice is still in the experimental stage in China.There are no mature methods to evaluate the resources reasonably at present and it lacks reference especially for evaluation of continental shale gas.Based on the analysis of differences and characteristics between marine shale and continental shale,the conditions and standards of terrestrial shale resource evaluation are confirmed.The continental shale gas resources are evaluated preliminarily on the basis of sample tests and gas content assessment of the Mesozoic Triassic Yanchang Formation shale in Yanchang exploration area.For different exploration degree and geological conditions,different assessing methods should be used.By a comprehensive evaluation,it is shown that the Mesozoic continental shale gas resource is of great value for exploration development;its volume is 626.4×108m3 to 6037.2×108m3.