东海陆架盆地西湖凹陷N构造带平湖组储层特征与主控因素  

Characteristics and main controlling factors of reservoir of Pinghu Formation in N tectonic zone,Xihu Sag,East China Sea Shelf Basin

作　　者：白洁 耳闯 刘建斌 何苗 李磊 胡崇 BAI Jie;ER Chuang;LIU Jianbin;HE Miao;LI Lei;HU Chong(School of Earth Sciences and Engineering,Xi'an Shiyou University,Xi'an 710065,China;Shaanxi Key Laboratory of Petroleum Accumulation Geology,Xi'an 710065,China;Shanghai Branch,CNOOC Ltd.,Shanghai 200335,China)

机构地区：[1]西安石油大学地球科学与工程学院,陕西西安710065 [2]陕西省油气成藏地质学重点实验室,陕西西安710065 [3]中海石油(中国)有限公司上海分公司,上海200335

出　　处：《天然气地球科学》2025年第3期493-507,共15页Natural Gas Geoscience

基　　金：国家自然科学基金“松辽盆地三肇凹陷扶余油层方解石胶结物形成机制及其烃类充注的耦合关系”(编号:41702132);西安石油大学研究生创新与实践能力培养计划(编号:YCS23213070)联合资助.

摘　　要：针对东海陆架盆地西湖凹陷N构造带平湖组储层分布特征与优质储层的成因机制认识不清等问题,利用岩石薄片、扫描电镜、XRD全岩矿物与黏土矿物、测井和测试等资料,分析储层特征以及优质储层的主控因素。结果表明:平湖组岩石类型以长石岩屑砂岩为主;岩性以细、中砂岩为主。储层主体埋深大于3400 m,原生孔隙以粒间孔为主,溶蚀孔隙以粒间孔隙为主。孔隙度为5.0%~23.60%,平均孔隙度为14.88%,中值为14.67%;渗透率为(0.10~1377.52)×10^(−3)μm^(2),平均渗透率为71.19×10^(−3)μm^(2),中值为3.99×10^(−3)μm^(2),整体为中孔—低渗储层。优质储层以中粗砂岩为主,砂体厚度一般大于10 m,石英含量为60.0%~84.0%,胶结物含量为1.0%~23.0%,孔隙度为15.0%~23.6%,渗透率为(1.7~1377.52)×10^(−3)μm^(2)。优质储层受沉积条件、成岩作用和超压等多种因素的影响。受潮汐作用影响,强水动力条件下发育的潮道、潮汐砂坝等类型的砂体以中粗砂岩为主,砂岩分选性好,泥质和杂基含量低,物性条件好。胶结物整体含量低且碳酸盐胶结物含量<8%时,对岩石骨架颗粒具有支撑作用,抵抗压实,对储层孔隙保存具有积极作用。溶蚀作用是改善深部储层物性的关键因素。薄煤层和暗色泥岩为溶蚀作用提供了良好的有机酸来源。当薄煤层离砂体顶底越近,溶蚀孔隙越发育,物性越好。因此,以中粗粒砂岩为主的潮道、潮汐砂坝砂体(厚度>10 m),为优质储层提供了良好的物质基础;煤层—泥岩—砂岩互层结构是最有利于溶蚀作用发生的岩性组合条件;生烃增压促进了有机酸流体运移,强化了溶蚀孔隙的形成和保存条件。In view of the unclear understanding of the reservoir distribution characteristics and the genetic mecha⁃nism of high-quality reservoirs in the Pinghu Formation of the N structural belt in the Xihu Sag of the East Chi⁃na Sea shelf basin,the reservoir characteristics and the main controlling factors of high-quality reservoirs are an⁃alyzed by using rock thin sections,scanning electron microscopy,XRD whole rock minerals and clay minerals,logging and testing data.The results show that the rock type of Pinghu Formation is mainly feldspar lithic sand⁃stone.The lithology is mainly fine and medium sandstone.The buried depth of the main reservoir is more than 3400 m.The primary pores are mainly intergranular pores,and the dissolution pores are mainly intergranular pores.The porosity is 5.0%-23.60%,the average porosity is 14.88%,and the median is 14.67%.The permea⁃bility is(0.10-1377.52)×10^(−3)μm^(2),the average permeability is 71.19×10^(−3)μm^(2),and the median is 3.99×10^(−3)μm^(2).High-quality reservoirs are mainly medium-coarse sandstone.The thickness of the sand body is gener⁃ally greater than 10 m,the quartz content is 60.0%-84.0%,the cement content is 1.0%-23.0%,the porosity is 15.0%-23.6%,and the permeability is(1.7-1377.52)×10^(−3)μm^(2).High-quality reservoirs are affected by vari⁃ous factors such as sedimentary conditions,diagenesis and overpressure.Under the influence of tide,the tidal channel,tidal sand dam and other types of sand bodies developed under strong hydrodynamic conditions are mainly medium-coarse sandstone.The sandstone has good sorting,low shale and matrix content,and good physical conditions.The overall content of cements is low and the content of carbonate cements is 10 m,which provides a good material basis for high-quality reservoirs.The interbedded structure of coal seam-mudstonesandstone is the most favorable lithologic combination condition for dissolution.Hydrocarbon generation pressur⁃ization promotes organic acid flow.

关 键 词：成岩作用 储层特征 成岩定量分析 超压 主控因素 平湖组 西湖凹陷 

分 类 号：TE122.2[石油与天然气工程—油气勘探]