基于跨频段实验的页岩油藏有利岩相弹性特征分析——以陈沱口凹陷新沟嘴组下段Ⅱ油组为例  

Analysis of elastic characteristics of favorable lithofacies in shalereservoirs based on cross-band experiment for oil group Ⅱ,a lowermember of the Xingouzui Formation,in the Chentuokou Sag

作　　者：肖增佳 赵建国[1,2] 钟庆良[3] 闫博鸿 李智 王荣峰[1,2] 欧阳芳 XIAO Zengjia;ZHAO Jianguo;ZHONG Qingliang;YAN Bohong;LI Zhi;WANG Rongfeng;OUYANG Fang(State Key Laboratory of Petroleum Resource and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;Unconventional Petroleum Research Institute,China University of Petroleum(Beijing),Beijing 102249,China;Research Institute of Exploration and Development,Jianghan Oilfield Company,SINOPEC,Wuhan 434124,China;Institute of Earthquake Forecasting,CEA,Beijing 100036,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)非常规油气科学技术研究院,北京102249 [3]中国石油化工股份有限公司江汉油田分公司勘探开发研究院,湖北武汉434124 [4]中国地震局地震预测研究所,北京100036

出　　处：《石油物探》2023年第6期1126-1141,共16页Geophysical Prospecting For Petroleum

基　　金：国家自然科学基金联合基金重点基金(U20B2015);国家自然科学基金项目(41574103,41974120,41804104和U19B6003-04);国家重大专项课题(2016ZX05004-003);中国石油科技创新基金项目(2018D-5007-0303)共同资助。

摘　　要：页岩油藏岩相复杂,纵向变化较快且非均质性强等因素导致“甜点”地震预测存在困难。明确复杂岩相地层的地震岩石物理特征,对提高测井解释和地震定量预测的精度具有重要意义。为此,对陈沱口凹陷新沟嘴组下段Ⅱ油组页岩油层系的33块取芯样品进行了物性和跨频段(低频1~1000 Hz,超声频段1 MHz)岩石物理参数测试。结合地质认识,分析了岩石弹性各向异性与成岩矿物、微观孔隙结构之间的机理联系,从而以岩石物理手段提供可识别有利岩相的跨频弹性属性。研究结果表明,新沟嘴组下段Ⅱ油组的页岩层系在该区具有极低孔隙度和超低渗透率,其白云石晶间孔隙发育较少,而纹层结构、陆源碎屑矿物及其含量对云质页岩的孔隙度有正向影响。此外,基于矿物和微观结构等物性数据与超声实验测量的弹性参数之间的关系表明,矿物组分和孔隙结构对页岩层系岩石的弹性性质影响较大;纹层状构造、水平裂缝和黏土矿物的定向排列是研究区弹性各向异性的主要原因。最后,基于典型岩心宽频测试数据和频散理论模型估算了全部岩心速度频散,以此提供识别有利岩相的跨频段(2.2,24.0,1.0×10^(4),1.0×10^(6) Hz)弹性参数组合分别为拉梅系数×密度和泊松比、纵波阻抗和纵横波速度比。研究结果可为岩石物理实验和理论建模为基础的跨频段(地震、测井和实验室超声)数据联合应用以及地震定量预测研究提供指导和数据支撑。It is difficult to predict the“sweet spot”owing to the complex lithofacies,rapid longitudinal change,and strong heterogeneity of shale reservoirs.It is important to clarify the physical characteristics of shale strata with complex lithofacies to improve the accuracy of logging interpretations and quantitative seismic predictions.In this study,33 samples were collected from the second oil group of the lower segment of the Xingouzui Formation in the Chentuokou Sag,and basic physical property measurements and cross-band rock physics experiments composed of low-frequency(1~1000 Hz)strain-stress tests and ultrasonic band(1 MHz)tests were conducted to obtain the rock physical parameters of the shales.Combined with geological understanding,we studied the correlation mechanism between the elastic anisotropy and physical properties of the reservoir in terms of lithology,diagenetic minerals,and microscopic pore structure to provide cross-band elastic attributes for the seismic identification of favorable lithofacies in shale reservoirs.The results showed that the shale strata of oil group II,the lower member of the Xingouzui Formation had extremely low porosity and permeability.Dolomite intergranular pores were less developed,whereas the laminated structure,terrigenous clastic minerals,and their contents positively affected dolomitic shale porosity.Moreover,the relationship between the physical data of the mineral and microstructure and the elastic property data measured by ultrasonic testing showed that the mineral composition and pore structure were the main factors influencing the elastic properties of shale.The acoustic anisotropy of the shale in the area was controlled by the laminated structure,horizontal fractures,and oriented alignment of clay minerals.Finally,the velocity dispersion of all samples was estimated based on the cross-band experimental data and dispersion theoretical model to provide cross-band(2.2 Hz,24.0 Hz,1.0×10^(4) Hz,and 1.0×10^(6) Hz)elastic parameter combinations ofλρ,ν,Z p,and v P/v S

关 键 词：页岩油藏 岩石物理实验 跨频段 有利岩相 弹性各向异性 

分 类 号：P631[天文地球—地质矿产勘探]