Barque Pre-SDM - Shallow Initial GeologicalModel Building, and Impact on Deep ReservoirImaging

摘要

To de-risk the development of the Barue PH01 extension, there was a need to further improve the qualityof the existing (2000) Pre-SDM imaging. Especially the shallow strata, i.e. the Liassic and the UpperTriassic, demonstrate a strong deformation. During the inversion of the Solepit basin they formed Riedelshears with strongly tilted fault blocks. The impact these dipping strata might have on the Pre-SDMvelocities has been recognised as one of the main causes of the pre-existing imaging uncertainties. Hence,in the new velocity-depth model-building exercise, most attention has been given to the construction of ageologically plausible velocity field for the shallow strata.As tomographic updating based upon RMOonly will most probably not give a satisfactory result due to lack of (shallow) offsets, an initial geologicalmodel has been built using sonic data, seismic dip, faults and paleo-surfaces. This initial model hassubsequently been updated using standard tomographic updating techniques. The final Pre-SDM image,resulting from this procedure, shows a marked improved over earlier depth imaging results; similarly, theexisting TZ-conversion uncertainties have been significantly reduced.