陆相页岩层系岩性组合模式及其对原油差异性富集的控制作用:以鄂尔多斯盆地三叠系延长组长7段为例  

Lithological Combination Model of the Continental Shale Series and Its Controls on Differential Crude Oil Enrichment:A Case Study of the Chang 7 Member of the Triassic Yanchang Formation in the Ordos Basin

作　　者：何鑫 陈世加[1,2,3] 胡琮 张海峰 牟蜚声[1] 陆奕帆 代林锋 付晓燕 韩玫梅 HE Xin;CHEN Shijia;HU Cong;ZHANG Haifeng;MOU Feisheng;LU Yifan;DAI Linfeng;FU Xiaoyan;HAN Meimei(College of Earth Science and Technology,Southwest Petroleum University,Chengdu,Sichuan 610500,China;State Key Laboratory of Reservoir Geology and Development Engineering,Chengdu,Sichuan 610500,China;Sichuan Key Laboratory of Natural Gas Geology,Chengdu,Sichuan 610500,China;Changqing Oilfield Company Exploration and Development Research Institute,PetroChina,Xi’an,Shaanxi 710018,China)

机构地区：[1]西南石油大学地球科学与技术学院,四川成都610500 [2]油气藏地质及开发工程国家重点实验室,四川成都610500 [3]天然气地质四川省重点实验室,四川成都610500 [4]中国石油长庆油田分公司勘探开发研究院,陕西西安710018

出　　处：《现代地质》2024年第5期1325-1337,共13页Geoscience

基　　金：国家自然科学基金项目(42072185、41872165);CNPC-SWPU创新联合体科技合作项目(2020CX030000、2020CX050000)

摘　　要：为明确陆相页岩层系原油岩性组合模式类型及其对原油富集的影响,优选下一步勘探的有利目标,本次研究在岩心观察与测井解释的基础上,通过储层物性测试、镜下观察、地球化学分析等技术手段,对鄂尔多斯盆地三叠系延长组长7段烃源岩和储层叠置关系与特征进行分析,并基于不同区块油藏解剖,探讨不同岩性组合模式对原油差异性富集的控制作用。本次研究将长7段岩性组合模式划分为8种类型(A型—H型)。其中,A型—C型为重力流型,以长7段发育厚层重力流砂体和黑色页岩与暗色泥岩为主要特征,A型、C型主要分布在陇东地区,B型在全盆地均有分布。D型—G型为三角洲前缘型,以发育三角洲前缘砂和暗色泥岩为主要特征,主要分布在陕北地区。H型为页岩型,长7_(3)至长7_(1)均为泥页岩,中间夹薄层泥页岩。重力流型(A型—C型)烃源岩有机质丰度明显好于三角洲前缘型(D型—G型)烃源岩,是重力流沉积地区原油富集程度高于三角洲前缘沉积地区的主要原因。B型、G型和H型储层物性最差,导致同一沉积地区、不同区块原油富集程度存在差异。不同岩性组合模式岩性变化控制不同亚段和不同区块原油富集程度,A型岩性组合原油富集程度最高,长7_(1)和长7_(2)均有规模性油藏被发现;G型岩性组合原油富集程度最低,长7_(1)至长7_(3)油藏零星分布。To clarify the lithological combination modes of continental shale strata and their influence on crude oil enrichment,targets for further exploration are determined.Based on core observations,log interpretations,and reservoir physical property tests,along with microscopic observations and geochemical analyses,we analyzed the superposition relationship and characteristics of hydrocarbon source rock and reservoirs in the Chang 7 Member of the Triassic Yanchang Formation in the Ordos Basin.Additionally,based on the reservoir anatomy of different blocks,we discussed how various lithological combination modes control the differential enrichment of crude oil.In this study,the lithologic combination model for the Chang 7 Member is categorized into eight types,labeled A through H.Among them,Types A to C are gravity flow types,characterized by the development of thick gravity flow sand bodies,black shale,and dark mudstone.Types A and C are primarily distributed in the Longdong area,while Type B is distributed throughout the entire basin.Types D to G are delta front types,characterized primarily by the development of delta front sands and dark mudstone,and are mainly distributed in Northern Shaanxi.Type H is the shale type,where Chang 7_(3) to Chang 7_(1) consist entirely of shale,with thin layers of shale in between.The organic matter abundance in gravity flow type(A-C)source rocks is significantly higher than in delta front type(D-G)source rocks.This is the primary reason why crude oil enrichment is greater in gravity flow sedimentary areas compared to delta front sedimentary areas.B-type,G-type,and H-type reservoirs have the poorest physical properties,which contributes to variations in crude oil enrichment within the same sedimentary area and across different blocks.Lithological changes associated with different lithologic combination modes control the degree of crude oil enrichment in various sub-members and blocks.The degree of crude oil enrichment is highest in A-type lithologic combinations,with large-scale reservo

关 键 词：岩性组合模式 富集控制机理 页岩层系原油 延长组长7段 鄂尔多斯盆地 

分 类 号：P618.1[天文地球—矿床学] P534.51[天文地球—地质学]