Full-Waveform Seismic Modeling Based on Digital Geological Model Using Spectral Element Method: Applications to Seismic Exploration

Abstract

Abstract ––The three-dimensional dynamic problem solution of the theory of elasticity as it applies to modeling of all types of seismic waves propagating in real geological media is considered. The elements of the 3D forward modeling algorithm based on the spectral element method (SEM) for the numerical solution of the problems posed are presented. The SEM’s main characteristics (high order spatial discretization, explicit time integration scheme) and its advantages are compared with the classical finite element method (FEM). Distinctive features of massively parallel implementation of this algorithm on NVidia’s GPU using CUDA (Compute Unified Device Architecture) are considered. The efficiency of parallelization on hybrid systems at different orders of SEM and parameters of the numerical scheme of time integration is analyzed. Results of solving a three-dimensional problem of modeling seismic wave propagation in a heterogeneous geological medium with faults and strongly varying (vertically and horizontally) properties of the investigated layers are presented. A highly detailed digital geological model constructed for one of the petroleum fields in the Arctic region using Petrel, the world’s most popular geological modeling tool, is used as input datasets. The problem was solved on a mesh of hexahedral elements in 3D to perform efficient SEM calculations in the CAE Fidesys software developed earlier with the authors participation for engineering simulations (strength analysis, etc.). The derivation of the model was based on the typical seismogeological conditions of Western Siberia so that the modeling allows investigating look-ahead capabilities of numerous seismic exploration methods for an in-depth study of major oil-and-gas-bearing complexes in this region. The prospects of model implementation for other candidate regions with different geological structure are equally promising. Outputs of the full-waveform seismic modeling is stored in the standard SEG-Y format currently widely used worldwide in industry for seismic data processing. The obtained synthetic seismograms and seismic wave fields are analyzed. The practical significance of the conducted research whose results can be utilized in the future for solving a wide range of applied tasks for regions with different geological conditions is deduced.