基于散射理论与动态时间规整的时移地震波动方程差异反演

时移地震勘探作为储层动态监测的有效手段, 对获取地下介质的弹性或物性参数变化起到了至关重要的作用.由于多期地震勘探之间介质的传播速度存在差异, 同时环境条件、采集方式及处理手段等方面的不同, 都会使地震记录产生走时差异.而这种走时差异对时移地震反演存在着严重的影响, 尤其是基于波动方程的反演方法.为了消除时移差异, 我们引入动态时间规整(DTW)方法实现角道集优化匹配, 以获取地震记录的有效变化信息.此外, 本文提出根据散射理论, 通过弹性波动方程进行时移地震差异反演, 得到地层的差异弹性参数, 实现储层差异定量表征.该方法采用WKBJ近似模拟非均匀背景, 具有更高的反演精度, 尤其是在复杂地质构造条件下优势更加明显.本文对所提出的方法进行了数值模拟实验与实际数据应用, 证明该方法得到的反演结果优于传统方法, 可以实现对地层时移差异的准确刻画.

Wave-equation-based time-lapse seismic inversion by using dynamic time warping and scattering theory

Time-lapse seismic exploration, as an effective means of reservoir dynamic monitoring, plays a vital role in obtaining subsurface media variation. Misleading travel-time differences will occur due to differences in environmental conditions, acquisition methods, and processing techniques between multiple periods of seismic data. To eliminate the travel-time discrepancy, we introduce the Dynamic Time Warping (DTW) method to realize the optimal matching of seismic angle gathers. Based on the effective variation information of different period seismic records, we propose time-lapse seismic difference inversion by elastic wave equation via scattering theory to yield the difference in elastic parameters of the formation and realize quantitative characterization of reservoir alteration. Our method adopts WKBJ approximates the inhomogeneous background, which has higher inversion accuracy, especially under complex geological conditions. Here, we carried out numerical simulation experiments and practical data applications on the proposed method, which proved that the proposed method allows for higher resolution inversion results and more precision characterization of stratigraphic changes than traditional methods.