3DSeismic Interpretation andDevelopment of Sequence Stratigraphic Model of a Carbonate Buildup in Central Luconia, Offshore Sarawak

The calibrated 3D seismic data were studied to characterize the carbonate facies in a carbonate buildup located in southeast Central Luconia Province. The sequence stratigraphy and seismic attributes analyses were carried on the carbonate bearing intervals to characterize the facies, understand the evolution and map-out their distribution. The carbonate bearing intervals, which is defined by Top Carbonate and Base Carbonate horizons were accumulated in Early Miocene to Middle Miocene time in two major sequences. These sequences were developed in response to the changes of relative sea level, with well defined associated system tracts. The stacking pattern of the system tracts and stratigraphic unit reveal the growth architecture and the evolution of the buildup. Three main factors have been identified in controlling the growth, evolution and architecture of the buildup; which are tectonics (faulting and subsidence), relative sea level and also paleowind direction in addition to the rate of carbonate production. Using seismic facies approach, the mounded reefal and progradational facies are potentially associated with good reservoir properties. They are extensive in peripheral area of the buildups, whereas the tight lagoonal facies is commonly found in the central of the buildup. The porosity and permeability enhancement through secondary processes such as karstification and late leaching has been identified as one of the main contribution to the reservoir formation. These facies is distributed in association with the formation of the sequence boundaries during lowstand sea levels. The findings from the study could contribute in lowering the future exploration and development risks and also to maximize the returns