东营凹陷低成熟页岩储集空间与分形特征——以民丰洼陷沙四段上亚段页岩为例  

Reservoir space and fractal characteristics of low-maturity shale in Dongying Sag:A case study of Upper Submember of Fourth Member in Eocene Shahejie Formation in Minfeng area

作　　者：王伟庆 王学军[1,2] 李政[1,2,3] 王玉环[1,2,3] 朱丽鹏 李朋波[1,2,3] WANG Weiqing;WANG Xuejun;LI Zheng;WANG Yuhuan;ZHU Lipeng;LI Pengbo(Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC,Dongying City,Shandong Province,257015,China;Key Laboratory of Shale Oil/Gas Exploration and Production,SINOPEC,Dongying City,Shandong Province,257015,China;Shandong Provincial Key Laboratory on Exploration and Development for Unconventional Oil and Gas(Preparation),Dongying City,Shandong Province,257015,China)

机构地区：[1]中国石化胜利油田分公司勘探开发研究院,山东东营257015 [2]中国石化页岩油气勘探开发重点实验室,山东东营257015 [3]山东省非常规油气勘探开发重点实验室(筹),山东东营257015

出　　处：《油气地质与采收率》2025年第2期14-24,共11页Petroleum Geology and Recovery Efficiency

基　　金：中国石化科研攻关项目“济阳坳陷及周缘页岩油资源分级分类评价与优选”(P22083)。

摘　　要：东营凹陷低成熟页岩分布广泛,具有丰富的页岩油资源,然而低成熟页岩的储集空间及分形特征尚不明确,制约了低成熟页岩油的高效开发。以东营凹陷民丰洼陷沙四段上亚段(Es4上)低成熟页岩为研究对象,利用岩心观察、薄片分析、有机地化测试、X射线衍射、低温氮气吸附、扫描电镜和能谱元素等手段,探讨低成熟页岩储集空间类型及纹层组合对储集空间发育的影响,并开展了孔隙分形特征研究。结果表明:研究区Es4上低成熟页岩岩相类型主要为富有机质纹层状灰质混合页岩和富有机质纹层状泥质混合页岩,其中前者以大介孔、大孔为主,后者以小介孔为主,并且发育较多大孔;低成熟页岩储集空间类型主要为晶间孔、黏土矿物片间孔和微裂缝。“泥晶方解石纹层+黏土纹层”和“亮晶白云石纹层+黏土纹层”2种纹层组合广泛发育,其中泥晶方解石纹层和亮晶白云石纹层以晶间孔为主,黏土纹层以黏土矿物片间孔为主,水平层理缝和晶间孔是页岩油重要的储集空间。低成熟纹层状页岩分形维数D1为2.4139~2.5277,D2为2.7046~2.8021。TOC、碳酸盐矿物含量与D1、D2均呈弱负相关关系,黏土矿物含量与D1呈弱正相关关系,碳酸盐矿物晶间孔和溶蚀孔表面光滑且孔隙空间简单,有利于页岩油的储集和渗流。Low-maturity shale is widely distributed in Dongying Sag,which has abundant shale oil resources.However,the reservoir space and fractal characteristics of low-maturity shale reservoirs are not clear,which restricts the efficient development of low-maturity shale oil.In this paper,the low-maturity shale in the Upper Submember of the Fourth Member in the Eocene Shahejie Formation(Es4 u)in Minfeng area of Dongying Sag was taken as the research object.The reservoir space types and the influence of lamina combinations on the reservoir space were discussed based on integrating core observation,slice analysis,organic geochemical test,X-ray diffraction,low-temperature nitrogen adsorption,and scanning electron microscopy,and the pore fractal characteristics were studied.The main lithofacies of the low-maturity shale of Es4 u in the research area are organic-rich laminated calcareous mixed shale and organic-rich laminated argillaceous mixed shale.The pores of the organic-rich laminated calcareous mixed shale are mainly mesoporous and macroporous,and those of the organic-rich laminated argillaceous mixed shale are mainly microporous,with some macropores also being developed.The predominant reservoir space in the low-maturity shales are intergranular pores,interlamellar pores in clay minerals,and micro-fractures.Two laminae combinations,“micrite calcite laminae+argillaceous laminae”and“sparry calcite laminae+argillaceous laminae”,are widely developed in the study area.The micrite calcite laminae and sparry calcite laminae are dominated by intergranular pores,while argillaceous laminae are dominated by interlamellar pores in clay minerals.The interlamellar fractures and intergranular pores are important reservoir spaces for shale oil.The fractal dimension D1 of low-maturity laminaceous shale ranges from 2.4139 to 2.5277,and D2 ranges from 2.7046 to 2.8021.TOC content and carbonate mineral content are weakly negatively correlated with D1 and D2,while clay mineral contents are weakly positively correlated with D1.The in

关 键 词：低成熟页岩 储集空间 分形维数 沙河街组 东营凹陷 

分 类 号：TE122.2[石油与天然气工程—油气勘探]