f Outcrop Analogs to The Offshore Sarawak Miocene Fields, How Effective Can They Be? The Subis Limestone as an Example

Outcrop models have typically been relied on to generate a proxy for subsurface reservoir distribution, and have been proven to provide a more complete view of both facies and reservoir quality. Despite the fact that the Tertiary carbonates of southeast Asia have been the subject of extensive exploration with proven reserves across the region, the subject of outcrop analogs have received little attention. This study focuses on the Subis Limestone Member of the Tangap Formation which forms the Gunung Subis: a huge flat-topped limestone hill that is exposed Onshore Sarawak. Satellite images of the structure were analysed confirming that it represents the original isolated carbonate platform. The platform was sampled at three main locations, depositional facies of the outcropping Subis Limestone include: lagoonal, back-reef, reef flat, reef-front, sand shoal and tidal channel. The Subis Limestone is proven to be very similar to the South China Sea carbonate buildups in terms of depositional setting and growth history. However, diagenetic history appears to be radically different. The analogy is discussed in this paper.