Publications

Fractured basement reservoirs play an important role in South East Asia oil and gas production with notable examples in Vietnam and South Sumatra. Assessment of the hydrocarbon potential within fractured basement reservoirs is dependent on our ability to characterize the fracture network. However, spatial definition of fracture orientation and distribution in an unstratified basement using seismic data is difficult, this is especially so at the Suban Field in the Corridor Block (South Sumatra, Indonesia) due to a combination of the impact of polyphase tectonics and basement lithological heterogeneity. The tectonic complexity of Suban field is due to multiple phases of tectonic events which have resulted in a complex network of faults and fractures. This is further complicated by the heterogeneous nature of the basement consisting of metamorphic and igneous rocks. Recent seismic re-processing of the Suban 3D seismic data using Controlled Beam Migration (CBM) has successfully improved seismic imaging for both horizon continuity and fault plane definition. A workflow incorporating volume curvature generated from the CBM seismic data was effectively used to map the basement fault networks. The seismically mapped faults are consistent with regional tectonic models and generally correlate with fracture azimuths from well data. A key finding is that volume curvature applied to CBM seismic data has enabled definition of previously unidentified subtle fault trends oblique to the primary compressional fault trends. These are being used as a primary input for constructing static and dynamic models and will have a significant impact on the modeled fractures and flow regimes. Owing to the low frequency nature of the seismic data at objective levels, smaller faults are expressed as “flexures”.