f Characterization of Reservoir Rock Types in a Laminated Thin Shale-Carbonate Reservoir

Identifying reservoir rock types in a laminated thin shale - carbonate reservoir is an essential component of reservoir characterization process. Reservoir characterization and rock typing together with post stack 3D seismic data analysis were carried out on Ngimbang laminated thin shale - carbonate formation to assess the petrophysical rock type distribution in Bukit Tua field. This predicted petrophysical rock type distribution provides valuable constraints for the development of the field. The calculated petrophysical rock types were obtained using Windland R35 equation which relates information collected from the core data. Several consistency check and quality control were applied to obtain the results which have a reliable relationship between petrophysical properties and rock types. The resulting curves at the depth interval of interest were correlated throughout the field and calibrated with 3D seismic data. Due to the thickness of the reservoir in Bukit Tua below the seismic resolution, the post stack 3D seismic data analysis is only used for structural mapping rather than inter-well petrophysical rock types distribution. Consequently, the geostatistical method is used to spatially distribute the petrophysical rock type. The results of rock type distribution clearly indicate the locations to be drilled either for appraisal or production well.