Publications

Hydrocarbon-producing basins across Southeast Asia possess distinct carbonate reservoirs. These characteristics are often derived from the dynamic essence of the carbonate and its post-depositional diagenesis, making some carbonate reservoirs stand out in terms of porosities, reservoir connectivity, and geometry. There will always be a new aspect of deposition and diagenesis to examine, making carbonate reservoirs some of the most challenging and exciting reservoirs to work with.

This publication documents examples of unusual carbonate reservoirs from the Gulf of Thailand, South Sumatra, Borneo, and the East Java region. The examples vary from heavily brecciated and vuggy pre-Tertiary carbonate reservoirs associated with the Ratburi Formation to mixed clastic-carbonate talus deposits from South Sumatra, Paleogene-Neogene brecciated and fractured karst-enhanced limestones from Northwest Borneo, and bioclastic carbonate rocks from offshore Indonesia. All showcased examples are related to the recent success exploration cases and producing carbonate reservoirs in Southeast Asia, which sometimes could not be found in other well-studied areas such as the Middle East, Zagros, Caribbean Sea and Gulf of Mexico.

The unusual characteristics and limited documentation of poorly understood carbonate reservoirs often provide new insights for future underexplored reservoir targets in mature areas. This paper proposes working models of depositional facies that are valuable for estimation purposes and their impact on prospecting activities, overcoming challenging drilling conditions, and optimizing specific formation evaluation practice. Valuable lessons may be applied to other areas with similar limestone reservoir characteristics across Southeast Asia.