摘要
大巴山冲断带下寒武统具有较好的页岩气发育物质基础,钻井显示了一定的资源潜力,但在强烈的构造作用下,构造保存条件具有复杂性和差异性,这也是影响该区下寒武统页岩气勘探的关键。采用野外地质调查、地球物理解释、分析测试等方法,将大巴山划分为5个页岩气构造保存单元,分别为南大巴山前缘褶皱单元(Ⅰ)、对冲断褶单元(Ⅱ)、叠瓦断夹片单元(Ⅲ)、北大巴山线状复式向斜—浅变质单元(Ⅳ)及穹窿状复式背斜—深变质单元(Ⅴ)。综合考虑大巴山抬升剥蚀作用、封盖条件、断裂发育、地层破碎程度、构造样式、变质作用与岩浆活动等构造因素对下寒武统页岩气保存的影响,对各构造保存单元进行分区评价,评价结果显示各构造保存单元保存指数分别为:Ⅰ:0.84;Ⅱ:0.72;Ⅲ:0.365;Ⅳ:0.54;Ⅴ:0.365。针对该区提出了圈闭保存型、断裂逸散型、散失残存型、散失破坏型等4种页岩气构造保存模式,其中,圈闭保存型比较有利于页岩气的富集与保存,主要表现在构造相对稳定宽缓的南大巴山前缘褶皱带,下寒武统埋深较浅的背斜构造是下一步页岩气勘探的有利方向。
The shale gas development material basis is relatively good in the Lower Cambrian in the Dabashan thrust belt,and the drilling data show potential of shale gas resources.However,as a result of intense tectonism,the shale gas tectonic preservation conditions are complex and diverse,and this is also the key to shale gas exploration of the Lower Cambrian.By the methods of field geological investigation,geophysical interpretation and analytical test method,etc.,Dabashan could be divided into five tectonic preservation units of shale gas,which includes south Dabashan mountain front fold unit（Ⅰ）,thrust fold unit（Ⅱ）,imbricate fault clip unit（Ⅲ）,north Dabashan linear compound synclinal-shallow metamorphic unit（Ⅳ）and fornix compound anticline-deep metamorphic unit（Ⅴ）.Comprehensively analyzing tectonic factors on the impact of Lower Cambrian shale gas preservation,such as Dabashan mountain uplift and denudation,sealed condition,fracture development,strata broken degree,tectonic style,metamorphism and magmatic activity,etc.,through zoning evaluation,the results show that preservation index of the tectonic preservation units respectively are：Ⅰ：0.84;Ⅱ：0.72;Ⅲ：0.365;Ⅳ：0.54;Ⅴ：0.365.Four kinds of shale gas tectonic preservation patterns are presented for this area,which includes trap preservation model,fracture dissipation model,loss residual model and loss damage model.Trap preservation model is more helpful for accumulating and preserving shale gas,which is mainly in relatively stable south Dabashan mountain front fold belt.The anticline structure with a shallow depth of Lower Cambrian is the beneficial exploration direction of shale gas of next step.
作者
余川
曾春林
周洵
聂海宽
余忠樯
Yu Chuan;Zeng Chun-lin;Zhou Xun;Nie Hai-kuan;Yu Zhong-qiang(National Joint Engineering Research Center for Shale Gas Exploration and Development,Chongqing Institute of Geology and Mineral Resources,Chongqing 400042,China;Chongqing Shale Gas Research Center of State Key Laboratory of Petroleum Resource and Prospecting,Chongqing 400042,China;Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083,China)
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2018年第6期853-865,共13页
Natural Gas Geoscience
基金
国家自然科学基金项目(编号:41202103)
重庆市国土房管局科技计划项目(编号:KJ-2018-028)联合资助
关键词
保存条件
保存指数
构造保存单元
页岩气
下寒武统
大巴山冲断带
Preservation condition
~ Preservation index
Tectonic preservation unit
Shale gas
Lower Cambrian series
Dabashan thrust belt
作者简介
余川（1985-），男，四川大竹人，工程师，硕士，主要从事页岩气地质勘探研究．E—mail：280850336@qq．com．
