| Popis: |
Summary Efficient suppression of receiver-side ghosts and free-surface multiples remains a challenge in processing of OBC/PRM data, and it is one of the key success factors for reliable extraction of 4D signals in time-lapse studies. A certain progress in solving this challenge can be achieved if PZ calibration factors and adaptive subtraction filters for removing the predicted multiples become angle-dependent. Due to the sampling issues for most of the OBC/PRM data, it is problematic to get receiver-side plane-wave decomposition directly by applying Radon transform on common shot gathers. In this work we suggest an efficient approach for wave-equation prediction of ghosts, PZ calibration, prediction and adaptive subtraction of multiples — with all steps performed on Radon transformed CR gathers. For time-lapse studies, the extraction of 4D signals can also be performed in the same domain, where the matching filters automatically account for angle dependent time shifts between base and monitor data. The effectiveness of the suggested approach has been demonstrated on 2D elastic FD synthetic data for a complex model from the Gullfaks field. |
