The appraisal and development of low permeability reservoirs require detailed knowledge of their quality and spatial variation. Different applications of 3D seismic data are used to map reservoir's property variation for subsurface characterization, including structural analysis, reservoir property mapping and seismic lithofacies prediction.
Seismic structural attributes were used to map large structural features that compartmentalize the reservoir and to identify enhanced natural fracture zones that may locally increase reservoir's permeability (‘sweet spots’). The prestack AVO and rock physics inversions are used for geomechanical properties calculations and total porosity and mineral fraction volume estimation. The inversion results were further extended for reservoir stress computation including pore pressure and effective stress estimations calibrated to pore pressure and DFIT measurements. Reservoir lithofacies volumes were generated using machine learning workflows and direct probabilistic inversion outputs, with the results generally matching the reservoir's lithology mapped from the core data.
Moving forward, the 3D seismic data can successfully assist the subsurface characterization of low permeability reservoirs and can be used to support well placement and to optimize the drilling and completion operations.