Publications

The Dayung Field, Corridor Block, South Sumatra produces gas from fractured and weathered Pre- Tertiary basement comprised of mixed basement lithologies. Reservoir characterization is therefore complex and challenging. Previously, a fracture “halo” modeling approach based on conventional seismic interpretation methods incorporating only the larger fault systems was employed providing a functional reservoir model. However, after fourteen years of natural gas production water encroachment has commenced at Dayung requiring a more detailed subsurface geological model to optimally manage the reservoir. To provide a more detailed interpretation of the fault and fracture network, 3D seismic structural attributes were utilized. Ant-Tracking proved to be the most useful attribute, and when combined with dip and azimuth attributes provided significant uplift in defining fault and fracture swarms. This method enabled improved controls for lateral distribution of fault and fracture networks near the top of Pre-Tertiary Basement reservoir. Fracture patterns from seismic attributes were verified by referencing to fractures observed in wells and regional structural stress studies. Possible pitfalls were analyzed. Application of this technique has significantly enhanced the subsurface model of fracture porosity distribution in the reservoir lending itself to be used to construct more detailed fracture networks in the static and dynamic models.