Publications

Uniform Field is a hydrocarbon field that produces from the Mio-Pliocene sand ridge reservoir of the Main & Massive Interval (Upper Cibulakan Formation). It is located in the offshore North West Java Basin. Interpreting Uniform Field is still challenging due to the factors that influence the sand ridge reservoir, such as the complexity of the reservoir distribution, the reservoir boundaries and reservoir properties that have resulted from the depositional system. The aims of this study are to not only obtain a better understanding of the ancient sand ridge distributions, geometry and properties, but also to better interpret all of the existing and developing fields by using width and thickness ratios from limited data. The Main & Massive Interval, the focus of this study, are sand ridges deposited in transgressive shallow marine environment. The N-S, NE-SW and NW-SE ridge orientations were the direct result of the combination of the wave and tidal influences, ancient coastal shapes and shelf morphologies. These influences have caused each sand ridge to have variations in both width and thickness. All the widths and thicknesses were collected and plotted to generate a width to thickness ratio which in turn was used to build a sand architecture model. Core analysis has helped to better understand the characteristics of the sand ridge reservoirs. This data shows that the bars consist of shaley sandstone which contains tidal sedimentation characteristics and stringers of Foraminiferal limestone. The shaley sandstone reservoir has an average porosity of 16% and an average permeability of 295 mD. It also has a length that ranges from 2 – 20 km, a width of 4 – 6 km, and a thickness of 15 – 65 feet. The results from this study show that the width and thickness sand ratio method is a very powerful tool to define the facies architecture, sand ridge distributions and properties of the ancient sand ridge reservoirs in the Uniform Field.