FRACTURED BASEMENT RESERVOIR CHARACTERIZATION LANGKAP FIELD, SOUTH SUMATRA BASIN, INDONESIA

• Main Author: WIBOWO PRAKOSO (NIM : 12010020), ADHI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/24985
• Institution: Institut Teknologi Bandung

<p align="justify"> South Sumatra Basin is one of the basins that has complex structural basement as well as one of the most productive basement reservoir in the world. Further analysis about basement reservoir in Langkap Field is required to understand the complexity of research area. The purpose of this research is to identify and characterize fractures, depth structure map, and understand historical geology as well as its correlation with the forming of fractures in basement interval of Langkap Field, South Sumatra Basin, Indonesia. The methods used are log interpretation, subsurface mapping, and cross section reconstruction. Tectonostratigraphy unit in research area is divided into three sequences which are pre-rift sequence (basement rocks), syn-rift sequence (Lemat Formation), and post-rift sequence (Talang Akar Formation, Baturaja Formation, Telisa Sandstone Member, Telisa Formation). Basement rocks in research area consist of marble and granite. Structures here have two main orientations which are NE-SW dan NW-SE. Fractures in research area are fault-related fractures, which the orientation tends to be NE-SW. The forming of fractures was controlled by fractures that had existed before: extensional deformation from Eocene to Early Oligocene and contractional in Pliocene to Pleistocene. Fractures’ density was controlled by lithology, karstification in marble basement, and damaged and localization zone. Productive fractures were developed in orientation that was parallel with in-situ stress which was NE-SW. Historical geology of research area begins with rifting from Late Eocene to Early Oligocene that deposited syn-rift sequence which is Lemat Formation. Post-rift sequence was then deposited after, which consist of Baturaja Formation, Telisa Sandstone Member, and Telisa Formation. During Pliocene to Pleistocene there was change of stress to NE-SW which caused reactivation and uplift.<p align="justify">