裂缝性低渗透油藏各向异性的尺度效应-石油勘探与开发.pdfVIP

　　　　　　 724 2007 12　　　　　　　　PET ROLEUM EXPLORATION AND DEVELOPMENT 　　　　　　　Vol.34　No.6　 :1000-0747(2007)06-0724-05 1 1 1 2 2 郝明强, 侯建锋, 胡永乐, 刘先贵, 杨正明 (1.中国石油勘探开发研究院;2.中国科学院渗流流体力学研究 ) :中国石油天然气股份有限公司科技信息部项目(040502-03) :在对低渗透储集层中发育的裂缝进行分组的基础上, 以分形几何为工具描述单组裂缝分布, 建立裂缝长度的幂律关系 式。根据裂缝渗透率的定义, 推导得到相互正交方向上的裂缝渗透率与考察尺度的关系表达式, 再加上基质渗透率的影响, 获得了储集层综合渗透率各向异性强度随考察尺度变化的关系式。研究表明, 裂缝性低渗透储集层中各向异性强度随考察 尺度的不同而变化, 同时说明, 通常 认为的各向异性强度为常值这 一观点仅是这 一表达式的某种特例。以发育2 组裂缝的 储集层为例, 详细讨论了各向异性强度随考察尺度变化的主要影响因素, 结果表明, 分形维数、夹角及长度初值比对各向异性 强度的变化影响显著, 基质裂缝渗透率比和基质各向异性强度对其的影响仅表现在某 一尺度范围内。 图5 表1 参21 :裂缝性低渗透油藏;各向异性;尺 效应;分形几何 :TE122.24　　　:A Scale effects of anisotropy in fractured low permeability reservoirs 1 1 1 2 2 HAO Ming-qiang , HOU Jian-feng , H U Yong-le , LIU Xian-gui , YAN Zheng-ming 1.Research I nstitute of Petroleum E xp loration Develop ment, PetroChina, Beij ing 100083, China; ( 2.Institute of Porous Flow F luid Mechanics, CA , Langf ang 065007, China) Abstract:Based on fracture strike grouping and the fractal geometry which was utilized to describe a single group of fractures, a power law expression of fracture length was established.According to the definition of fracture permeability, an analytical expression of fracture permeability in the orthogonal orientation was obtained.Then, a scale transformation formula of anisotropy was derived with the matrix influences combined.The results show, infractured low permeability reservoirs, anisotropy varies with scale transformation;accordingly only under very few special conditions does the conclusion of anisotropy being a constant come into existence.With two groups of fractures as examples, the fac