A high-resolution method for processing coal measures seismic data based on anisotropic medium theories and its application

[Objective] The increasing importance of the exploration and exploitation of deep resources poses new requirements for high-precision seismic exploration. Given that conventional isotropy-based data processing methods are no longer applicable to the coal-bearing strata with strong anisotropy. [Methods] This study proposed a method for processing seismic data based on theories of both transverse isotropy medium with a vertical symmetry axis (VTI) media and transverse isotropy with a horizontal axis of symmetry (HTI) media. First, to characterize the depositional characteristics of coal-bearing strata, this study analyzed the features of VTI media, revealing that high-order dynamic correction can effectively eliminate anisotropy-induced event bending in large-offset seismic data, thus ensuring that the common reflection points in both far and near channels can be in-phase and improving the data stacking and imaging quality. Second, targeting the characteristics of tectonic fissures, this study relied on the azimuthal anisotropy analysis of HTI media. Specifically, using Offset-Vector Tiles (OVT) domain processing, the influence of varying azimuthal differences on data was removed by establishing the parameter fields of azimuthal anisotropy. Using both methods, this study developed a practical processing and correction method suitable for target strata with anisotropy by establishing a rational process and choosing optimal key parameters. This method can achieve effective velocity analysis and data stacking of coal-bearing strata under complex conditions, thus improving the resolution and interpretation accuracy of coal measures seismic data. [Results and Conclusions] The application results indicate that the new method can obtain seismic data with higher dominant frequency and a wider frequency band and is more advantageous in identifying the features of small structures and characterizing paleogeographic environments, thereby providing strong support for the fine-scale geological interpretation. This study highlighted the necessity of the processing of anisotropy for coal-bearing strata, potentially promoting the applications of anisotropy processing techniques in wide-azimuth seismic explorations. © 2024 Science Press. All rights reserved.