摘要
【目的】中国陆相页岩油资源十分丰富,勘探潜力巨大。目前济阳坳陷沙一段页岩油的勘探开发已取得实质性突破,但不同岩相泥岩间的储集性差异还存在一些问题尚待解决。【方法】选取济阳坳陷沙河街组泥岩为研究对象,采用X射线衍射、岩石热解、荧光分析、扫描电镜、低温气体吸附等研究手段,详细探讨了渤南洼陷沙一段纹层状泥岩纹层类型、纹层组合及纹层组合的孔隙类型和孔隙结构特征。【结果】沙一段泥岩矿物类型多样,根据成分不同,将研究区泥岩中纹层划分为长英质纹层、黏土矿物纹层、文石纹层、泥晶方解石纹层和富有机质纹层五种类型,根据其垂向叠置关系划分为“富有机质+泥晶方解石质”“富有机质+文石质”“富有机质+长英质”三种二元纹层组合。其中,“富有机质+文石质”和“富有机质+长英质”二元组合泥岩的孔隙度相对较高,且孔隙结构与连通性优于“富有机质+泥晶方解石质”二元组合泥岩。在“富有机质+文石质”二元纹层组合泥岩中,页岩油以游离态赋存于层间缝中,可动性最好;“富有机质+文石质”二元纹层组合泥岩中游离油与吸附油共存,可动性相对较差;而在“富有机质+长英质”二元纹层组合泥岩中页岩油主要以吸附态形式存在,可动性最差。【结论】不同泥岩的孔隙度、孔隙结构及油气富集机理受到纹层组合形式的决定性控制作用,其油气赋存模式可以为未—低成熟度页岩油开采起到指导作用。
[Objective]China possesses abundant terrestrial shale oil resources with significant potential for explora⁃tion.Now,substantial breakthroughs have been made in the exploration and development of shale oil in the Shahejie Formation(Es1)in Jiyang Depression,but there are still some problems to be solved in the differences of reservoir properties among black mudstones of different lithofacies[.Methods]This study focused on the black mudstone of the Shahejie Formation in the Jiyang Depression,southern Bohai Bay Basin.The laminated strata types and combina⁃tions,pore types and structures were examined by X-ray diffraction(XRD),rock pyrolysis,fluorescence analysis,scanning electron microscopy(SEM)and low-temperature gas adsorption.[Results]Five distinctive categories of mineral types were identified:feldspar-quartz lamina,clay mineral-rich lamina,aragonite lamina,micritic calcite-dominated lamina,and organic-rich lamina.Their vertical stacking occurs in three binary layer combinations:organic-rich+micritic calcite,organic-rich+aragonite,and organic-rich+feldspar-quartz.The porosities of the organic-rich+aragonite and organic-rich+feldspar-quartz binary lamina combination mudstones are higher than the other combinations,and possess better pore structure and connectivity.In the organic-rich+aragonite combination,shale oil is present in a free state within interlayer spaces,and is the most mobile.The mobility of the free oil and adsorbed oil in the organic-rich+aragonite mudstone is poorer.The lowest-mobility oil occurs mainly as adsorbed material in the organic-rich+feldspar-quartz combination mudstone[.Conclusions]The different strata combinations in the mudstone structure influence the porosity,pore structure and hydrocarbon storage capacity of these black mud⁃stones.Based on the findings of this study,shale oil reservoir storage models were developed for each combination to provide a rational foundation for the future extraction of shale oil and gas in the region.
作者
董济凯
董春梅
林承焰
赵子茹
郑心如
刘连启
聂聪
刘斌
DONG JiKai;DONG ChunMei;LIN ChengYan;ZHAO ZiRu;ZHENG XinRu;LIU LianQi;NIE Cong;LIU Bin(School of Geosciences and Technology,China University of Petroleum(East China),Qingdao,Shandong 266580,China;National Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao,Shandong 266580,China;Oil Production Plant,Shengli Oilfield Company,SINOPEC,Dongying,Shandong 257200,China)
出处
《沉积学报》
北大核心
2025年第6期2151-2167,共17页
Acta Sedimentologica Sinica
基金
国家自然科学基金项目(42372156)
山东省重点研发计划(竞争性创新平台)(2022CXPT048)。
关键词
泥岩
纹层类型及组合
储集特征
赋存模式
渤海湾盆地
mudstone
lamina type and combination
reservoir properties
occurrence pattern
Bohai Bay Basin
