Abstract：Prestack reverse time migration requires computing the first breaks time of imaging points. The ray-tracing approach is usually used for the computation of travel time because of higher computational efficiency, but difficult to handle the rapid velocity variation and irregular grid. Common-used finite-element algorithm also has same data dispersion problem as the finite-difference algorithm when solving the wave equation. Different from the common finite-element algorithm, the finite-element algorithm presented in the paper for solving the wave equation and gaining seismic first breaks time is using lumped mass matrix to suppress time dispersion,which makes the feature of wavefront hi-fi. The paper gives the method for computation of first breaks time according to first extreme appearing time of source wavelet. The numeric simulation results showed that the approach is suitable for the irregular grid and rapid-changed velocity interface.
薛东川, 王尚旭. 利用有限元解波动方程求取初至时间[J]. 石油地球物理勘探, 2007, 42(3): 259-262.
Xue-Dong-chuan, Wang Shang-xu. Computation of first breaks time by using finite-element algorithm for solving wave equation. OGP, 2007, 42(3): 259-262.
