摘要
了解储层岩石的介电特性在石油工业的各个方面都有重要的应用.小尺度裂隙是影响岩石介电性质的地质因素之一,获得裂隙对含裂隙岩石介电性质影响的定量关系具有重要的理论和实践意义.以含裂隙人造砂岩的三维微观数字结构为基础,通过基于三维有限差分算法计算的岩石介电性质与实验数据的对比验证数值计算方法的有效性.在此基础上,通过理论模型获得不同孔隙度基质的介电性质,并在不含裂隙人造砂岩的三维微观数字结构中人为添加以裂隙密度和纵横比为定量表征参数的裂隙,应用验证后的数值算法模拟随频率变化的含裂隙砂岩的介电性质,分析和研究不同孔隙度基质中定向排列裂隙对砂岩介电性质的影响.结果表明,当裂隙孔隙度随裂隙纵横比或裂隙密度发生改变时,含裂隙砂岩的介电性质与裂隙密度以及裂隙纵横比呈正相关关系,而当裂隙孔隙度保持不变时,含裂隙砂岩的介电性质随裂隙纵横比的减小而增大;裂隙参数的改变对不同基质孔隙度的含裂隙砂岩的介电性质的影响趋势较为一致,但随着基质孔隙度的减小,裂隙对砂岩介电性质的影响逐渐增大.裂隙参数和基质孔隙度对含裂隙砂岩介电性质影响的研究结果为基于介电特性的裂缝性油气储层的定量表征提供了依据,在油气勘探开发中具有重要的应用前景.
Understanding the dielectric properties of reservoir rocks has significant applications in all aspects of the petroleum industry.Small-scale fractures are one of the geological factors that affect the dielectric properties of rocks.Obtaining the quantitative relationship of the influence of fractures on the dielectric properties of fractured rocks has important theoretical and practical significance.Based on the three-dimensional microscopic digital structure of artificial sandstone with fractures,the validity of the numerical calculation method is verified by comparing the dielectric properties of the rock calculated based on the three-dimensional finite-difference algorithm with the experimental data.The dielectric properties of the matrix(i.e.,the rock without fractures)with various porosities are then determined using the multiphase incremental model,the validity of which is tested using the measured results of the unfractured sample.Finally,fractures with varying crack density and aspect ratio are artificially added into the CT structure of the matrix to form new fractured rocks,and their dielectric properties are simulated using the validated three-dimensional finite-difference model.The results show that the influences of fractures on the dielectric properties of the sandstone increase with the decrease of porosity of the sandstone matrix,and the dielectric properties of the fractured sandstone are positively correlated with fracture density and fracture aspect ratio when fracture porosity changes with fracture density or fracture aspect ratio.However,the dielectric properties of the fractured sandstone increase with the decrease of fracture aspect ratio as fracture porosity unchanged.The variation of the fractures impacts the dielectric properties of the fractured rocks with varying matrix porosity in a similar trend,but the amount of the impact increases with decreasing matrix porosity.The research results of the influence of fracture parameters and matrix porosity on the dielectric properties of fractured sandstones provide a basis for the quantitative characterization of fractured oil and gas reservoirs based on dielectric properties,and have important application prospects in oil and gas exploration and development.
作者
李博
韩同城
符力耘
LI Bo;HAN TongCheng;FU LiYun(School of Geosciences,China University of Petroleum(East China),Qingdao Shandong 266580,China;Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology,Qingdao Shandong 266071,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第12期4578-4591,共14页
Chinese Journal of Geophysics
基金
国家自然科学基金(41874151,41821002)
中央高校基本科研业务费(18CX05008A)资助.
关键词
岩石物理
数字岩心
介电性质
裂缝性储层
Rock physics
Digital rock
Dielectric properties
Fractured reservoir
