The Influence of Permian Igneous Rock on the Seismic Imaging of Underlying Strata in Halahatang Area

In order to get an accurate seismic imaging of the strata covered by thick igneous rock, based on well drilling, logging data and seismic data, the Cambrian-Cretaceous simplified geologic model, the elastic wave equation is calculated by the finite difference method, the forward equation simulation is used for wave equation, the true restoration seismic imaging process is carried out, to discuss the influence of seismic imaging for the underlying strata form the Permian igneous rock body, to guide the Paleozoic oil/gas exploration and development. The results show that the high-speed and high-density Permian dacite have shielding effect on the seismic imaging of the underlying strata, and the amplitude of the reflected wave of the underlying strata is obviously weakened relative to the periphery of the covering area. Due to the lateral mutation of the lithology, the seismic imaging of the layers has obvious deformation and tectonic anomalies, rather than the seismic response of the fault zones or volcanic channels. The wavefield of fracture-cavern body in the disorder reflection region and underlying region of volcanics is very complex and the imaging velocity is difficult to pick accurately, which leads to distorted migration results and not convergent bead-like reflection.