OVERPRESSURE ANALISYS BASED ON WIRELINE LOG DATA IN BGM FIELD, JAMBI SUB-BASIN, SOUTH SUMATRA BASIN

• Main Author: SYAFRIYA ( NIM: 22013305), ANDRI
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/25559
• Institution: Institut Teknologi Bandung

<p align ="justify">The Jambi Sub-basin is located in the northern parth of the South Sumatra Basin. This Basin is an overpressured basin although until quite recently the generating mechanism of the overpressure is still unknown. In this research, the overpressure zone is identified and its magnitude is estimated, by using wireline logs in combination with drilling data and other supporting data. These informations are expected to be able to describe overpressure characteristics in the study area, especially in BGM Field, in Jabung Block, South Sumatra Basin. The overpressure zone could be identified from wireline log data especially from porosity, density, sonik, and pressure data. The generating mechanism of overpressure is identified from Dutta’s cross plot from 11 wells, and vitrinite reflactance data in BGM Field. Based on Dutta cross plot data from some wells show the precense of smectite to illite transformation with depth. This circumstance indicates that the overpressure in some wells is caused by smectite to illite transformation. Based on wireline log data in 11 wells in the BGM Field, at the top of Upper Talangakar there is reversal in the sonik log, while the density log behaves normally, i.e. increasing density value with increasing depth. This zone is indetified as top of overpressure caused by non-loading mechanism. At the top of overpressure, the source rock has reached its maturity (Ro > 0,6), therefore it can be inferred that the source rock maturation also plays a role in the overpressuring in this area.<p align ="justify">