--> --> 4-D CSEM, A Cost-Effective Tool for Deep-Water Clastic Reservoir Monitoring

2018 AAPG International Conference and Exhibition

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4-D CSEM, A Cost-Effective Tool for Deep-Water Clastic Reservoir Monitoring

Abstract

We performed a complete sensitivity study in the Jubarte oilfield RO-300 reservoir (offshore Campos Basin, Brazil) to appraise the applicability, potential and limitations of the marine CSEM method to monitor deep-water clastic reservoir production. Such study is based on present-day CSEM acquisition, operation and data interpretation technologies. The RO-300 Jubarte reservoir is the first fully optical deep water Permanent Reservoir Monitoring (PRM) seismic system installed in Campos Basin. This reservoir was selected to introduce highly realistic models and production effects, usually rare in the literature, in the development, understanding and assessment of the sensitivity of EM fields to water-flooding in complex and heterogeneous deep water clastic oil reservoirs. This study based in fluid substitution indicates that production effects and associated variations in saturation translate into changes of the reservoir’s resistivity structure over time. We demonstrate that coupled ‘constrained’ inversion can retrieve reservoir production-related resistivity differences. On the other hand, coupled ‘localized’ inversion focused where reservoir’s volume variations are expected to occur, improves resolution in the identification of parameter changes, even in the presence of repeatability problems. We ultimately provide the step change technology development to transform marine CSEM into a trusted and cost-effective tool to integrate with time-lapse seismic for deep-water clastic reservoirs monitoring.