PORE PRESSURE AND OVERPRESSURE GENERATING MECHANISM ANALYSIS IN BULA BASIN, SERAM, MALUKU

• Main Author: LUKMAN - NIM: 22014311 , ALI
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/25377
• Institution: Institut Teknologi Bandung

<p align="justify">The Bula Basin Basin is a Neogen sedimentary basin located in the northeastern part of Seram Island, Maluku. There are two different geological conditions in this basin, i.e the fold thrust belt composed by Triassic to the Early Miocene sediments and the foreland basin composed by Middle Miocene up to Pleistocene sediments. The analysis of pore pressure and generating mechanism of overpressure in Bula Basin were conducted by observing five wells, namely North Bolifar 1, East Nief 1, Oseil 1, 2 and 4. This study aims to analyze the pore pressure condition in different geological condition as described above . <br /> <br /> <br /> The methods used to fulfill the above objectives are observation and analysis of data comprising chronological data of drilling, pressure, stress, and wireline log. The biostratigraphy data and cuttings were used to analyze burial history curve that is useful to determine the sedimentation rate. <br /> <br /> <br /> One well in the foreland basin area, namely North Bolifar 1 is known to be in overpressured condition with its top is located at the depth of 3.100 ft in the Salas Formation interval. The mechanism of the overpressure in the well is caused by disequilibrium compaction due to the high sedimentation rate of 732,76 m/million years and also influenced by clay diagenetic process. The other four wells are in hydrostatic condition down to the total depth. Oseil 1, 2 and 4 wells show a deflection of density and sonic log data, and it is interpreted as the result of lithology repetition in the thrust fold belt zone. <br /> <br /> <br /> The result of this research indicate that the difference in pore pressure condition of the five wells is caused by the difference in geological condition. The hydrostatic wells are located in the folding belt zone, while the overpressured well is located in the foreland basin zone.<p align="justify"> <br /> <br />