Publications

The successful prediction of mapping the spatial reservoir properties distribution like porosity is essential for geological analysis of field development and evaluation. The Sintong Field was discovered in 1971. It consists of 4 (four) formations of Sihapas Group - Duri, Bekasap, Bangko and Menggala FM. The best producing oil sand is the Bekasap X sand, with an average thickness of 50 ft, deposited in estuarine, intertidal, inner-outer neritic environment. Its lateral porosity variation affects the sand quality distribution and reservoir performance. One methodology to predict the spatial distribution of a reservoir property is by combining petrophysical and geophysical attribute data. One prerequisite to a successful application of this methodology is that the time seismic data is properly aligned with the depth well data. In Sintong, 14 (fourteen) wells were used to create synthetic seismograms with a consistent phasewavelet. A velocity model was then developed to insure a good translation of time to depth in order to properly pick the correct time seismic events that correspond to the depth geological markers of the reservoir target. Detailed structure horizons were interpreted including top and bottom of Bekasap X sand. A set of average seismic horizon attributes from the Bekasap X interval were extracted to relate with reservoir properties from log-derived data. Empirical relationships between log reservoir properties and seismic horizon attributes were computed by cross plotting between a set of average seismic attributes and a set of average petrophysical properties obtained from 34 well-log data in the interest zone interval. The best empirical seismic attribute-porosity relationship was selected and applied to estimate and map the average reservoir porosity distribution. The reservoir seismic-derived porosity was then cross-plotted with saturation water to estimate fluid saturation. The final average porosity and water saturation maps were used to reduce geologic uncertainty and optimize cost in well placement of development drilling plans, evaluate existing well placements and recognize potential field compartmentalization related to structure, stratigraphy or porosity.