Publications

South Mahakam Cluster is an offshore gas field located in the Mahakam PSC Block. It is formed by multi-layer deltaic reservoirs with complex geological structures known as the Sepinggan Fault Zone. It is believed that Sepinggan Fault Zone plays a major role in sand distribution, geometry, and lateral connectivity across the whole field. This paper aims to explore the impact of the Sepinggan Fault Zone on reservoir modelling and how it is able to improve the static geological model for a full field scale.

Detailed interpretation of seismic and well data is needed for a better understanding of the structural framework and reservoir distribution knowledge. Therefore, the results indicate that the Sepinggan Fault Zone influences sediment accumulation and accommodation, with its orientations aligned with the main depositional trend. Fault activities in the proximal area show increasing sand preservation and connectivity, causing thicker and continuous reservoir units, while in distal areas, sand distribution tends to be less with lower continuity due to accommodation limitation and fault offsets.

The integration of QPSDM 2020 seismic reprocessing into geological models has greatly improved the accuracy of fault geometry interpretation and its interaction with sand bodies. This allows for more accurate reservoir boundary determination, improving reservoir target identification, and supporting future drilling campaigns.

Understanding the structural complexity of the Sepinggan Fault Zone is essential for improving reservoir characterization and distribution in this cluster. The findings of this study provide a more robust geological framework that enhances reservoir modeling accuracy and supports more effective hydrocarbon recovery. These insights help minimize subsurface uncertainties, improving future well candidate planning in the South Mahakam Cluster.