黑色页岩微裂缝发育控制因素——以长宁双河剖面五峰组—龙马溪组为例  

Factors controlling microfractures in black shale: A case study of Ordovician Wufeng Formation-Silurian Longmaxi Formation in Shuanghe Profile, Changning area, Sichuan Basin, SW China

作　　者：董大忠[1,2,3] 施振生 孙莎莎[1,2,3] 郭长敏 张晨晨[4] 郭雯 管全中[5] 张梦琪 蒋珊 张磊夫 马超 武瑾[1,2,3] 李宁 昌燕[1,2,3] DONG Dazhong;SHI Zhensheng;SUN Shasha;GUO Changmin;ZHANG Chenchen;GUO Wen;GUAN Quanzhong;ZHANG Mengqi;JIANG Shan;ZHANG Leifu;MA Chao;WU Jin;LI Ning;CHANG Yan(Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China;National Energy Shale Gas R&D(Experiment)Center,Langfang 065007,China;CNPC Key Laboratory of Unconventional Oil&Gas Resources,Langfang 065007,China;Sinopec Exploration&Production Research Institute,Beijing 100083,China;China University of Petroleum,Beijing 102200,China;School of Earth and Space Science,Peking University,Beijing 100871,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]国家能源页岩气研发(实验)中心,河北廊坊065007 [3]中国石油天然气集团有限公司非常规油气重点实验室,河北廊坊065007 [4]中国石化石油勘探开发研究院,北京100083 [5]中国石油大学(北京),北京102249 [6]北京大学地球与空间学院,北京100871

出　　处：《石油勘探与开发》2018年第5期763-774,共12页Petroleum Exploration and Development

基　　金：国家自然科学基金项目"晚三叠世四川盆地不同类型三角洲内部构型及成因模式"(41572079);国家科技重大专项"大型油气田及煤层气开发"(2017ZX05035-001)

摘　　要：以长宁双河剖面奥陶系五峰组—志留系龙马溪组为例,重点讨论黑色页岩微裂缝发育控制因素及页岩气储集层"甜点段"微裂缝成因。针对目标层段,开展了203块大薄片、203块小薄片、110块TOC样品、110块X-衍射全岩和103块主微量样品测定与分析。结果表明,黑色页岩微裂缝分为顺层缝和非顺层缝,顺层缝多为层面滑移缝、页理缝和构造雁列缝,非顺层缝主要为剪切缝和拉张缝。纵向上,龙马溪组SLM1段微裂缝密度最高,SLM2段至SLM5段微裂缝密度逐渐降低,五峰组微裂缝密度最低。微裂缝密度与黑色页岩硅质含量正相关、与碳酸盐矿物含量负相关,黑色页岩颗粒越细微裂缝密度越大。微裂缝密度受控于生物成因硅含量,生物成因硅含量越高微裂缝密度越大,在应力作用下,微裂缝优先在细粒页岩的纹层界面处形成。区域性构造活动是龙马溪组页岩气储集层"甜点段"微裂缝形成的关键因素,成岩收缩是页理缝形成的重要动力,生烃增压是微裂缝大量发育主要原因。The dominant factors controlling development of microfractures in the black shale and the origin of microfractures in the sweet spot intervals were discussed of the Ordovician Wufeng Formation?Silurian Longmaxi Formation in Shuanghe outcrop profile,Changning,Sichuan Basin.For the target interval,holographic photograph statistics of microscopic composition of 203 big thin sections and 203 small thin sections,TOC content of 110 samples,110 whole rocks X-ray composition,and main trace elements of 103 samples were tested and analyzed.The results show that the microfractures include bedding microfractures and non-bedding microfractures.The bedding microfractures are mostly plane slip microfractures,lamellation microfractures and echelon microfractures.The non-bedding microfractures are largely shear microfractures and tension microfractures.Vertically,the density of microfractures is the highest in SLM1 Member of Longmaxi Formation,decreases from SLM2 Member to SLM5 Member gradually,and drops to the lowest in Wufeng Formation.The microfracture density is positively correlated with siliceous content and negatively correlated with the carbonate content.The finer the grain size of the black shale,the higher the density of the microfractures is.The microfracture density is controlled by biogenic silicon:the higher the content of biogenic silicon,the higher the micro-fracture density is.Under the effect of ground stress,microfractures appear first in the lamellar interfaces.Regional tectonic movements are the key factor causing the formation of microfractures in the sweet spot interval,diagenetic contraction is the main driving force for lamellation fractures,and pressurization due to hydrocarbon generation is the major reason for the large-scale development of microcracks.

关 键 词：微裂缝 有机质含量 纹层 岩性 黑色页岩 志留系龙马溪组 奥陶系五峰组 四川盆地 

分 类 号：TE122[石油与天然气工程—油气勘探]