Integrated Reservoir Characterization of Complex Globigerina Limestone Reservoir in Madura Strait: Case Study of MAC Field

This study examined a complex Globigerina Limestone reservoir in the MAC field, Madura Strait, Indonesia. The goal was to obtain an understanding of the reservoir characterization using the combination of seismic inversion, facies association, and rock type identification.

Petrographic analysis plays important role in the lithofacies and rock type identification. Five rock types were identified, showing different relationship of porosity and permeability, and associated with certain pore type and size. Moreover, facies development generally controlled by paleo-depositional structure. The sediments were winnowed by the currents and deposited in a clinoform pattern. This structure has four recognized facies associations: restricted shelf, upper-middle foreslope, and lower foreslope.

Seismic inversion was used to predict porosity distribution across the reservoir, aiding in reservoir characterization. Gas presence gives additional effect to the seismic response. Based on AI, gas reservoir is well separated from the non-gas reservoir. Secondary porosity commonly appears, showing that diagenetic processes significantly altered the original pore system, but depositional environment also influenced the type of secondary porosity formed.

Reservoir model shows a good relationship between rock type and well’s productivity, associated with high porosity and permeability. The outcome of this study can be used as the intake for further development plan.