Abstract

The 34-1 Sandstone is one of six productive reservoirs in the Widuri field, which is located in the Asri Basin, within the Southeast Sumatra Production Sharing contract between Pertamina and Repsol-YPF. The Widuri field is located 60 miles Northeast offshore from Jakarta.

The aim for this study was to characterize the reservoir in terms of log patterns, porosity, quality and depositional environment, and to establish the distribution of the reservoir in the Widuri field. The data used for the study of 34-1 reservoir sandstone are mainly logs, cores, and 3D seismic data.

The 34-1 reservoir is characterized by a blocky log character to bell-shaped fining upward, fine to coarse grained sands with excellent porosity and permeability. The sands are well sorted, oil stained, and have common cross bedding, with occasional carbonaceous laminae. The reservoir thickness is in the range of 10 to 53 feet.

Based on the results of the analyses, it can be summarized that the 34-1 sandstone was deposited in the fluviodeltaic setting which has four subfacies - distributary channel, shallow marine clay, marine embayment and swamp. The channel facies distribution can be traced by 3D seismic data which shows an approximately east - west trend.