An Alternative True-amplitude Common-shot Reverse Time Migration
Y. Li and H. Chauris
Event name: 79th EAGE Conference and Exhibition 2017
Session: Velocity Model Estimation - Theory A
Publication date: 12 June 2017
Info: Extended abstract, PDF ( 1.81Mb )
Price: € 20
In a given correct background velocity model, conventional migration methods accurately position reflectors but generally fail to recover amplitudes, typically small scale velocity perturbations. The reason is that migration, adjoint of the modeling operator, does not compensate for geometrical spreading, uneven illumination nor limited acquisition geometry. We provide a wave-equation-based shot-profile constant density true-amplitude migration formula. This is a variant compared to a recently published approach, that better behaves in the presence of heterogeneities close to the source position. The formula is derived from the asymptotic ray-based approach, but the final expression only contains wave-equation-based operators. This pseudo-inverse outputs velocity variations with correct amplitudes and phases, in the sense that Born modeling reproduces the data with good accuracy. We validate the method on the Marmousi model.