Sponsor(s):China National Petroleum Corporation
6 issues per year
Current Issue: Issue 06, 2020
Oil Geophysical Prospecting publishes new theories, methods, technologies, and new experiences within the field of exploration geophysics. The scope of the journal covers the seismic data collection, analysis, comprehensive interpretation, and nonseismic exploration. The goal of the journal is to provide valuable information for the scientific and product workers.
Editor-in-Chief Qian rongjun Associate Editor-in-Chief Feng Xiaoqiu Feng Xingzhi
Oil Geophysical Prospecting,2020,Vol 55,No. 06
The numerical solution to wave equation is the computational engine of many high-precision imaging and inversion methods in seismic exploration. To ensure accuracy, regular methods generally set a fixed spatial sampling interval according to the minimum velocity of the model. This always causes over sampling in high velocity layers, and the calculation is redundant to some extent. Under the compaction of rocks caused by gravity, the wave propagation speed usually increases along with depth. The trapezoid coordinate transformation can incorporate the general increasing trend of wave velocity. Then we propose seismic wave simulation with a trapezoid-grid pseudo-spectral method. We use the trapezoid grid based on trapezoid coordinate transformation to divide media. The fine grid is used in the shallow low-velocity region and the coarse grid is used in the deep high-velocity region, which can reduce the number of sampling points. Meanwhile, considering the accuracy of wave field simulation, we use the pseudo-spectral method to solve the acoustic wave equation with variable coefficients after coordinate transformation and use the perfectly matched layer to eliminate the fictitious return wave caused by artificial boundary. The test on the Marmousi model shows that compared with that of the general method, the number of grids generated by trapezoidal grid can reduce by about 69%, and compared with that of the regular-grid pseudo-spectral method and the high-order finite difference method, the calculation time of the trapezoid-grid pseudo-spectral method can respectively reduce by 58% and 60%. Therefore, this method is an efficient high-precision method for seismic wave simulation.