Removal of surface-related multiples from marine seismic data: A field data example

Removal of the effects of the free surface from seismic reflection data is an essential pre-processing step before pre-stack migration. The problem can be formulated by means of Rayleigh's reciprocity theorem which leads to an integral equation of the second kind for the desired pressure field, that does not include these free-surface effects. In order to solve the integral equation an estimate for the source wavelet is required. To obtain an accurate estimate for the source wavelet the minimum energy criterion is employed. The energy minimization problem is solved using a modified conjugate gradient method. As a result, a causal estimate for the source wavelet is obtained. The method is applied to a marine field data set and demonstrates the effectiveness of the procedure.