摘要
水力压裂微地震监测技术的核心是准确获取微地震震源位置和震源机制信息.然而,震源位置与震源机制之间存在固有耦合,若单独反演易导致误差.此外,忽略非常规油气储层中普遍存在的各向异性特征,也会进一步降低反演精度.本文提出了一种基于各向异性介质的多道波形二维互相关联合扫描方法,可同步求解微地震震源位置与震源机制.通过合成数据和四川盆地某页岩气储层水力压裂实际微地震监测数据进行验证.合成数据结果表明,该方法在各种噪声条件下均能准确反演震源参数.对比分析各向同性(ISO)和垂直横观各向同性(VTI)模型的反演结果发现,未考虑地层各向异性会导致震源深度反演偏差和滑动角计算误差.实测数据分析进一步验证了各向异性对震源深度和滑动角参数均具有耦合影响.研究结果表明,在微地震反演中引入各向异性模型,对于提升震源参数反演的分辨率与可靠性具有重要意义.
Accurate determination of microseismic source locations and mechanisms is central to hydraulic fracturing monitoring.However,the inherent coupling between source location and mechanism often leads to errors in separate inversions.Furthermore,neglecting the pronounced anisotropic characteristics of unconventional oil and gas reservoirs can further degrade inversion accuracy.This study presented a joint scanning inversion approach that simultaneously estimates microseismic source locations and focal mechanisms by leveraging 2D cross-correlation of multi-channel waveforms in anisotropic media.The method was validated using both synthetic data and field data from a shale gas reservoir in the Sichuan Basin.Synthetic test demonstrated the method's robustness under varying noise levels,accurately recovering source parameters.Comparative analysis between isotropic(ISO)and vertically transverse isotropic(VTI)models revealed that ignoring anisotropy results in systematic errors,particularly in source depth and slip angle estimation.Field application further corroborates these findings,demonstrating that anisotropy exerts a coupled influence on both focal depth and fault slip characteristics.These results underscore the necessity of incorporating anisotropy into microseismic inversions for improved resolution and reliability in reservoir characterization.
作者
赖浩宇
王一博
武绍江
LAI HaoYu;WANG YiBo;WU ShaoJiang(Key Laboratory of Deep Petroleum Intelligent Exploration and Development,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《地球物理学报》
北大核心
2025年第7期2669-2683,共15页
Chinese Journal of Geophysics
基金
国家杰出青年科学基金项目(42025403)
国家自然科学基金项目(41904054)
中国科学院稳定支持基础研究领域青年团队计划(YSBR-020)资助。
关键词
微地震监测
各向异性
震源定位
震源机制
互相关联合扫描
Microseismic monitoring
Anisotropy
Source location
Focal mechanism
Cross correlation joint scanning
