DEREVERBERATION OF MARINE REFLECTION SEISMIC DATA BY A SPATIAL COMBINATION OF PREDICTIVE DECONVOLUTION AND VELOCITY FILTERING

Contamination of seismic reflection records at early times by first-or der water reverberations can be especially severe during survey operat ions over hard and flat sea floors on the continental shelf or in lake environments. A new dereverberation scheme based on two classical tec hniques - predictive deconvolution and velocity filtering - has been d eveloped to address this problem. The techniques are combined spatiall y to take advantage of their complementary offset - and time-dependent properties. Stage I of the scheme consists of applying predictive dec onvolution at short offset, The data are previously conditioned by a n ormal moveout correction with the water velocity which restores the pe riodicity of the reverberations in the offset-time plane and enhances the performance of deconvolution. Stage II of the scheme involves velo city filtering in the common-midpoint domain which is particularly eff ective at long offset where the moveout difference between primary ref lections and reverberations is largest. The dereverberation scheme is well suited for the initial processing of large volumes of data due to the general availability of cost-effective deconvolution and velocity filtering algorithms in seismic processing software packages. Practic al implementation issues are illustrated by a field example from the G LIMPCE survey in Lake Superior.