Depth-Extrapolation-Based True-Amplitude Full-Wave-Equation Migration from Topography

The lack of an initial condition is one the major challenges in full-wave-equation depth extrapolation. This vertical partial derivative surface wavefield and cannot be provided by conventional seismic acquisition system. traditional solution to use value calculate assuming that velocity constant. However, for exploration on land, often not uniform. To solve this problem, we propose a new method calculating from without making any assumptions about conditions. Based calculated derivative, implemented depth-extrapolation-based migration topography using direct downward continuation. We tested imaging performance our proposed with several experiments. results Marmousi model experiment show superior reverse time (RTM) algorithm terms accuracy amplitude-preserving at medium deep depths. In Canadian Foothills experiment, proved can still accurately image complex structures maintain amplitude under topographic scenario.