RESERVOIR GENETIC ANALYSIS OF ’34-SAND’ AND ITS IMPLICATIONS TO RESERVOIR MANAGEMENT STRATEGIES IN WIDURI AND INDRI OILFIELD, ASRI BASIN, SOUTEAST SUMATERA

• Main Author: Nurzaman, Roby
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/73043
• Institution: Institut Teknologi Bandung

Reservoir ’34-Sand’ is a siliciclastic sandstone reservoir that become the main contributor on oil production in Widuri and Indri oilfield, Asri basin. The Reservoir ’34-Sand’ in both fields has been interpreted genetically as a fluvial channel facies although some analitical studies and production data have shown several indications or even evidences of contrary. This research is trying to define the Reservoir ’34-Sand’ in a more comprehensive manner, and also to reveal any possible heterogeneity in the reservoir that might been caused by its genetic history. By this, we may expect to be able to apply a better, more effective and more efficient reservoir management strategy in both fields. The scientific method used in this research is analysis and re-interpretation of data set (cores, thin sections, SCAL, routine core analysis, well logs, 3-D seismic attributes, production, and biostratigraphic analysis). After the reservoir genetic of each field is clearly defined/ interpreted, then the more effective and efficient reservoir management strategies for each field are set up afterward. The result shows that in general, the genetic of Reservoir ’34-Sand’ in both fields is exremely different. Reservoir ’34-Sand’ in Widuri Field is a quartz arenitesubarkose fluvial-distributary channel sandstone in lower part and transformed upward gradually to tidal dominated deposits of estuarine channel and associated facies as transgression occurred. Whereas, in Indri Field, the reservoir is a quartz arenite of intertidal-subtidal bar. Nevertheless, the Reservoir ’34-Sand’ in both fields seem to have a relatively same diagenetic degree. According to their characteristics, the diagenetic phase of Reservoir ’34-Sand’ in both fields are categorized as immature stage mesogenetic. Therefore, primary porosity almost entirely posseses the total percentage of pores in the rock. Real implementation of this reservoir genetic analysis in both fields is by drafting and applying reservoir management strategies for each field in several aspects as follows; oil recovery, oil lifting, completion design, well trajectory design, production maintenance, and further field development scenarios.