نوع مقاله : مقاله پژوهشی
نویسنده
گروه مهندسی معدن، دانشکده فنی و مهندسی، دانشگاه لرستان، خرم آباد، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسنده [English]
Reverse Time Migration (RTM) is one of the most effective seismic imaging methods for complex geological media because it solves the full two-way wave equation and accurately images steeply dipping structures and strong velocity contrasts. In this study, the numerical solution of the acoustic wave equation using the finite-difference method was investigated for seismic imaging of complex geological media using RTM. Temporal derivatives were discretized using a second-order approximation, while spatial derivatives were approximated using a fourth-order scheme in order to preserve numerical stability and achieve sufficient accuracy in wavefield propagation. To evaluate the performance of the algorithm, wavefield propagation was first simulated in a homogeneous medium using a Ricker wavelet with a dominant frequency of 25 Hz, and the effects of different temporal sampling intervals on the accuracy of wavefield extrapolation were examined. Subsequently, the RTM algorithm was applied to the complex SEG/EAGE salt dome model to assess the efficiency of the method under complicated geological conditions. For this purpose, migrated images obtained using time intervals of 2, 4, 6, and 8 ms were compared. The results showed that for time steps of 2 and 4 ms, subsurface structures and salt dome boundaries were imaged accurately with negligible numerical dispersion effects. In contrast, for larger time intervals (6 and 8 ms), the quality of the migrated images decreased significantly, and artificial artifacts appeared in the final images. It was also observed that although smaller time steps improve imaging accuracy, they increase computational time and processing cost. Therefore, a time interval of 4 ms was selected as the optimal compromise between numerical accuracy and computational efficiency.
کلیدواژهها [English]
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