海陆过渡相页岩气储层特征与主控因素——以鄂尔多斯盆地大宁—吉县区块二叠系山西组为例  

Reservoir characteristics and its influence on transitional shale:An example from Permian Shanxi Formation shale,Daning-Jixian blocks,Ordos Basin

作　　者：张琴[1,2] 邱振 张磊夫[1,2] 王玉满 肖玉峰 刘丹[1,2] 刘雯 李树新[3] 李星涛 Qin ZHANG;Zhen QIU;Leifu ZHANG;Yuman WANG;Yufeng XIAO;Dan LIU;Wen LIU;Shuxin LI;Xingtao LI(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;China National Energy Shale Gas Research(Experiment)Center,Langfang 065007,China;PetroChina Coalbed Methane Company,Beijing 100028,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]中石油煤层气有限责任公司,北京100028

出　　处：《天然气地球科学》2022年第3期396-407,共12页Natural Gas Geoscience

基　　金：中国石油勘探开发研究院院级项目“中国典型盆地页岩油气重点层系有机质富集机理研究与主控因素分析”(编号:2021yjcq02);中国石油十四五前瞻性基础性项目“海陆过渡相页岩气成藏条件及勘探前景评价研究”(编号:2021DJ2001)联合资助。

摘　　要：鄂尔多斯盆地东缘大宁—吉县地区二叠系山西组山_(2)段为海陆过渡相沉积,其中山_(2)^(3)亚段具有页岩厚度大、夹层少而薄的特点,是目前中国海陆过渡相页岩气勘探开发的重点目标层段,但其储层特征等相关研究相对较少,特别是优质储层发育的主控因素有待进一步明确。综合利用有机地球化学分析、矿物成分分析以及储层微观刻画等技术手段,对大宁—吉县区块山_(2)^(3)亚段的储层特征进行系统研究并探讨优质储层发育的主控因素。研究结果表明:山西组山_(2)^(3)亚段上部潟湖相(底部)页岩层段具有高TOC含量、高脆性矿物含量、高BET和高BJH的特征,是最优质的页岩气储集层段;山_(2)^(3)亚段页岩孔隙构成以黏土矿物晶间孔为主体,占总孔隙体积的76.9%,有机质孔占18.7%;扫描电镜观察显示不同矿物组分的孔隙大小分布特征不同,其中有机质孔和方解石溶蚀孔以中孔为主,黏土矿物与石英则主要发育中孔与宏孔,黄铁矿与长石孔径范围分布广,且分布较为均匀。单因素分析显示黏土矿物含量是影响山_(2)^(3)亚段海陆过渡相页岩孔隙发育的第一控制要素,有机质含量对页岩孔隙发育存在着一定影响,有机质类型则对页岩孔隙发育的影响不明显。The shales in the 2^(nd)member of Shanxi Formation in the Daning-Jixian blocks,east margin of the Ordos Basin were deposited in a marine-continental transitional environment during the Permian.The Shan_(2)^(3)submember is characterized by large thickness,few and thin interlayers,which is the key target for transitional shale gas exploration and development.However,there are relatively few related studies on the reservoir characteristics,especially the main controlling factors for the development of the high quality reservoirs need to be further clarified.In this paper,the reservoir characteristics of Shan_(2)^(3)sub-member in Daning-Jixian blocks are systematically studied and the main controlling factors of high quality reservoir development are discussed by using geochemical analysis,compositional analysis and microscopic characterization method.The results indicate that the lower section of the upper lagoon facies in the Shan_(2)^(3)sub-member has the characteristics of high TOC content,high brittle mineral content,high values of BET and BJH,which is the sweet spot for shale gas exploration and development.Pores developed in clay minerals and in organic matter contribute most to the porosity of the Shan_(2)^(3)sub-member,accounting for 76.9%and 18.7%of the total porosity respectively.SEM observation(resolution>6 nm)discloses that different components in shale have great difference in pore size distribution,and the pores developed in organic matter and calcite are mainly in meso-scale.The pore size distribution characteristics of clay minerals are similar with quartz pores where pores developed both in meso and macro scale.The pores developed in feldspar and pyrite distribute in a wide range and the distribution is relatively uniform.Single factor analysis shows that the content of the clay minerals is the dominant controlling factor for pore development in the Shan_(2)^(3)sub-member.The organic matter content has a certain effect on the pore development of shale,but the influence of the organic matter type on

关 键 词：海陆过渡相 页岩气 二叠系山西组 储层特征 

分 类 号：P618.13[天文地球—矿床学]