鄂尔多斯盆地三叠系延长组7段陆相页岩油层系岩石物理性质变化规律  

Rock physical properties and variation patterns of Chang 7 lacustrine shale oil reservoir in the Triassic Yangchang Formation,Ordos Basin

作　　者：谭开俊[1,3] 邓继新 刘忠华[4] 黄军平 夏辉[3] TAN KaiJun;DENG JiXin;LIU ZhongHua;HUANG JunPing;XIA Hui(PetroChina Research Institute of Petroleum Exploration and Development-Northwest,Lanzhou 730020,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Department of Geophysics,College of Geophysics,Chengdu University of Technology,Chengdu 610059,China;Petrochina Research Institute of Petroleum Exploration and Development,Beijing 100083,China)

机构地区：[1]中国石油勘探开发研究院西北分院,兰州730020 [2]油气藏地质及开发工程国家重点实验室(成都理工大学),成都610059 [3]成都理工大学地球物理学院地球物理系,成都610059 [4]中石油勘探开发研究院,北京100083

出　　处：《地球物理学报》2025年第2期652-667,共16页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(42474149,41774136);中国石油天然气股份有限公司前瞻性基础性战略性技术攻关项目(2021DJ0401)联合资助.

摘　　要：陆相页岩油气储层是中国油气工业勘探开发的重要接替领域之一,但由于对陆相页岩油储层岩石物理特征缺乏系统研究,制约了页岩油层系地质与工程“甜点”地震评价方法的有效运用.为此,以鄂尔多斯盆地三叠系延长组7段陆相页岩油储层为例,通过对泥页岩样品的岩石学特征、储层特征与岩石物理特征的系统测试,分析了页岩油样品的岩石物理变化规律及影响因素,确定不同特征泥页岩样品表现出地震弹性特征差异的关键地质因素.研究结果表明,长7段页岩主要为灰白色凝灰质黏土质页岩、黑色黏土质页岩和灰色粉砂质泥页岩三种主要岩相类型,分别对应“富有机质纹层+富凝灰质纹层”、“富有机质纹层+长英质纹层”和“贫有机质黏土纹层”三种纹层组合类型,构成孔隙类型以黏土粒间孔为代表的无机孔隙为主.不同岩相类型样品纹层组成差异会造成宏观地震岩石物理性质表现出整体分区分布的特征,弹性波垂直层理传播时岩石样品的力学响应特征倾向于等应力状态,其弹性模量受控于样品中“软”组分“等效有机质层”所占比例,造成对应速度和弹性模量随有机质含量增大呈幂指数降低的整体趋势;弹性波平行层理传播时,岩石样品的力学响应特征倾向于等应变状态,其等效弹性模量为组成部分对应弹性模量的算术平均,造成对应速度和弹性模量随有机质含量增大呈线性降低的整体趋势.黏土颗粒优选定向排列的程度和条带状有机质占比差异是造成页岩样品出现速度各向异性明显变化的主要原因.不但形成各向异性系数随黏土含量增大而逐渐增大的整体趋势,也造成相同黏土含量下凝灰质黏土质页岩样品、黏土质页岩样和粉砂质页岩样品各向异性系数依次降低.研究结果可为陆相页岩油储层“双”甜点的测井与地震评价提供理实验基础和理论支撑.Lacustrine shale oil reservoir is one of the important succeeding fields in the hydrocarbon exploration and development in China.However,due to the lack of systematic research on the rock physical characteristics of lacustrine shale oil reservoir,the effective application of seismic method on the geological and engineering“sweet spot”evaluation is restricted.Therefore,taking the 7th member of Yanchang Formation in Ordos Basin as an example,through the systematic testing of the petrological characteristics,reservoir characteristics and rock physical characteristics of shale samples,the variation patterns and influencing factors of the rock physical properties are analyzed,and the key geological factors for the variations in seismic elastic properties of shale samples are also determined.The research results show that the Chang 7 shale samples are mainly composed of three lithofacies types:grayish-white tuffaceous argillaceous shale,black argillaceous shale sample and gray silty mudstone,consisting of“organic-rich lamina+tuff-rich lamina”layer,“organic-rich+silt-grained feldsparquartz”laminae combination,and“organic lean clay silty lamina”layer,respectively.The pore type is mainly inorganic pores represented by clay intergranular pores.The permeability shows apparent anisotropic characteristics.The laminae combination differences of shale samples will cause the corresponding seismic rock properties to show the characteristics of regional distribution.When the elastic wave propagates in the direction vertical to the bedding,the rock sample is in the state of equal stress,and its effective elastic modulus are controlled by the proportion of the“soft”component-“effective organic layer”in the sample,resulting in the overall trend of the corresponding velocity and elastic modulus decreasing exponentially with the increase of the organic matter content.When the elastic wave propagates in the direction parallel to the bedding,the rock sample is in an equal position,the effective elastic modulus are

关 键 词：岩石物理性质 陆相页岩油 三叠系延长组 鄂尔多斯盆地 各向异性 

分 类 号：P631[天文地球—地质矿产勘探]