基于弹性波速径向变化的岩石脆裂性定量评价.PDF

2016 6 PETROLEUM EXPLORATION AND DEVELOPMENT Vol.43 No.3 417 文章编号：1000-0747(2016)03-0417-08 DOI: 10.11698/PED.2016.03.12 基于弹性波速径向变化的岩石脆裂性定量评价 唐晓明，许松，庄春喜，苏远大，陈雪莲 （中国石油大学（华东）地球科学与技术学院） 基金项目：国家重点基础研究发展计划（973 ）项目（2014CB239006 ）；国家自然科学基金）； 中央高校基本科研业务费专项资金（14CX05010A，16CX06040A ）；山东省自然科学基金（ZR2014DL009 ） 摘要：岩石的脆性和可压裂性是非常规油气储集层体积压裂重要的岩石力学参数，为获得地层岩石的脆性和可压裂 性指标，基于声波测井得到的井壁地层纵、横波速度的径向变化，求得地层的脆裂指数，指导储集层压裂改造作业。 钻井过程中岩石破坏时在井壁地层中产生微裂缝，导致弹性波速度降低，波速在径向上发生由小到大的变化。采用 测井纵波速度的层析成像和偶极弯曲波频散特征反演获得井壁周围地层纵、横波速度径向剖面，将两个剖面沿井径 方向积分，得到纵、横波脆裂指数。脆裂指数与脆性指数、可压裂指数相关性较好，验证了用脆裂指数评估岩石脆 裂性质的有效性；实际对测井数据的处理和分析亦证明了这种方法的可行性和有效性，结果对于储集层压裂优选层 位和压裂改造实施有指导意义。图7 表 1 参 17 关键词：岩石脆裂性；脆裂指数；声波速度径向变化；声波测井；弹性波速 中图分类号：P618 文献标识码：A Quantitative evaluation of rock brittleness and fracability based on elastic-wave velocity variation around borehole TANG Xiaoming, XU Song, ZHUANG Chunxi, SU Yuanda, CHEN Xuelian (School of Geosciences Technology, China University of Petroleum, Qingdao 266555, China) Abstract: Brittleness and fracability are two important rock properties in hydraulic fracturing of unconventional reservoirs. Based on the variation of compressional and shear velocity around borehole using acoustic measurement, an effective technique is developed to estimate these parameters to guide reservoir-fracturing. During drilling, when the rock is broken, a significant amount of drilling induced cracks will occur in the formation around the borehole, resulting in the drop of radial elastic wave velocity and the wave velocity variation from low to high in radial direction. The radial variation of compressional and shear velocities of formation rocks surrounding a borehole were respectively obtained from P-wave travel time tomography and dip