陕南西乡——镇巴地区龙马溪组页岩气成藏地质条件评价  

Evaluation on reservoir-forming conditions of Longmaxi Formation,Xixiang-ZhenBa area,southern Shaanxi

作　　者：谢青 许锋 王宁 许婷 黄薇 XIE Qing;XU Feng;WANG Ning;XU Ting;HUANG Wei(Shaanxi Center of Mineral Geological Survey,Xi'an 710068;Shaanxi Institute of Geological Survey,Xi'an 710054)

机构地区：[1]陕西省矿产地质调查中心,西安710068 [2]陕西省地质调查院,西安710054

出　　处：《矿产勘查》2018年第9期1675-1682,共8页Mineral Exploration

基　　金：陕西省西乡-镇巴地区页岩气地质调查(编号20180116)资助

摘　　要：西乡—镇巴地区位于华南板块扬子陆块北缘,构造系统复杂,黑色页岩较发育,前人对其页岩研究较少。利用野外调研、钻测井及实验等方法,结合前人研究成果,以西乡—镇巴地区龙马溪组页岩为研究对象,对其烃源岩、储层特征及保存条件等进行了详细分析。研究结果表明:研究区页岩厚度大、分布广,烃源岩有机质丰度高、成熟度高,有机质类型主要为I型干酪根,也有部分II型。储层脆性矿物含量高,天然裂缝较多,粘土矿物含量相对少,主要为伊利石,其次为绿泥石和伊蒙混层;孔隙度、渗透率较低,属低孔、低渗储层。成岩作用类型主要有压实-压溶作用和有机质成熟作用。保存条件良好、埋深厚度大、岩性致密、封闭性较好。研究区龙马溪组具备较好的页岩气成藏地质条件。Xixiang-Zhenba area is located in the northern margin of the Yangtze block of the Southern China plate and has complex structure system.Black shale is relatively developed which have been studied little.Based on field investigation,experiment analysis,drilling-logging data and previous research results,taking the Longmaxi Formation shale of Xixiang-Zhenba area as the research object,the source rock and reservoir characteristics and preservation conditions are analyzed in detail.The results show that the thickness of shale in the study area is large and widely distributed,and the abundance and maturity of organic matter in source rocks are high.The main types of organic matter areⅠtype kerogen and partⅡtype.The reservoir is characterized by high content of brittle minerals,more natural fractures and relatively less clay mineral content,mainly illite,followed by chlorite,illite and montmorillonite mixed layer.Porosity and permeability are relatively low,it belongs to low porosity and low permeability reservoir.The main diagenesis types are compaction,pressure dissolution and maturation of organic matters.The preservation condition is good:the depth is large,the lithology is dense and the sealing is good.The Longmaxi Formation in the study area possesses favorable shale gas reservoir-forming conditions.

关 键 词：页岩气藏 烃源岩 储集条件 龙马溪组 西乡-镇巴地区 

分 类 号：P618.13[天文地球—矿床学]