Investigation of viscoelastic anisotropy in wavefield simulations and their response characteristics for Gulong shale oil within the Songliao basin

The shale oil resources of the Qingshankou Formation in the northern Songliao Basin exhibit substantial potential, highlighting extensive opportunities for exploration and development. However, the Gulong area is controlled by factors such as bedding density, fractures, and formation pressure, showing pronounced characteristics of strong anisotropy and attenuation in geophysical properties. Such factors lead to a complex seismic response mechanism in Gulong shale, leaving the response characteristics somewhat ambiguous. To tackle the viscoelastic anisotropy characteristics of the Gulong shale formation, a multi-faceted fusion approach integrating well logging data, seismic stratigraphy, structural features, and core experiments was utilized. This method refined the initial model through meticulous stratification, enabling the development of a high-precision and sophisticated viscoelastic anisotropy model on a meter scale for the Gulong shale area. The wave equation grounded on the constitutive relationships of a viscoelastic vertically transverse isotropy (VTI) medium model was developed. The staggered-grid finite difference algorithm was employed for the numerical simulation of the seismic wavefield in the Gulong shale formation. Findings reveal that under explosive source or shear-wave source conditions, the seismic amplitude of the Gulong shale is markedly influenced by the viscoelastic anisotropy. The seismic response outcomes under the strong anisotropy and attenuation characteristics in the Gulong area underscore the importance of incorporating Q-compensated anisotropic imaging technology for achieving high-precision seismic imaging in the region.