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Logs for Normal-Incidence
Getting Synthetic Seismograms to Tie to Seismic Data
| The Problems | ||
| Why don't Synthetics tie? | How did this happen? | Relative Importance |
| Well logs are incorrect | Shifts at log-run changes; borehole rugosity; formation damage from drill-string; tool malfunction; mis-calibration; digitizing errors; erroneous log scales; etc, etc. | Almost always the primary cause |
| Seismic is incorrect | Wrong amplitude recovery, poor phase recovery, migration issues (subsalt) | Rarely seen in modern data |
| Wavelets are incorrect | Most software does not support well-based wavelet extractions | Usually the secondary cause |
| The Solution | ||
| Action | Explanation | |
| 1. | Purify the Well Logs using proprietary techniques by Loren & Associates, Inc. | There is a tremendous amount of redundancy in logs, which can be used to determine which sections of a log curve are faulty, and to replace them with calibrated synthetic values. The result is a harmonious set of log curves, proven to create better synthetic seismograms. |
| 2. | Extract the Wavelets using the purified Well Logs | A zoned multi-well wavelet extraction will usually create beautiful synthetic seismograms, not just visually adequate, but mathematically precise. |
| 3. | If extractions indicate a problem with seismic, reprocess | Occasionally problems with true-amplitude recovery, or other processing, is demonstrated by the behavior of the wavelets. |
| 4. | Use wavelets for advanced techniques | Inversion, AVO, and many other advanced techniques are only as precise as the wavelets involved. |
| 5. | Use wavelets for pressure prediction | The wavelets, and the inversion they make possible, are the best pressure-prediction tools available. |
