f Post stack and prestack seismic interpretation for structural depth model estimation

In case of lateral velocity variations and of dipping events, depth migration is the adequate processing to obtain seismic images directly interpretable in terms of geological structures . However this technique involves estimation of a detailed depth model in which lateral velocity variations are taking info account. Due to difficulties in determining a correct structural model, depth migration is often used as an iterative and interpretive process. Therefor a sequential strategy of seismic processing and interpretation may be redefined as an incremental proces of structural model building. This structural model is defined in depth and is viewed as the sum of two types of model: a geometrical model which describes reflector geometry and a velocity model which gives an estimate of the intra-bed velocities used for time-depth conversion. Relations between geometrical and velocity models are guided by geological reasoning.