THE ANALYSIS OF THE OCCURANCE AND ITS GENERATING MECHANISM OF OVERPRESSURE IN OFFSHORE EAST JAVA

• Main Author: Valdo (NIM : 22014049), Charlianto
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26240
• Institution: Institut Teknologi Bandung

<p align="justify">The East Java Basin is one of the sedimentary basins with a fairly intensive oil and gas exploration activity. One of the most common problems in this basin is the overpressure occurence in the drilling well. The study was conducted in four wells located in the offshore East Java. The presence of overpressure in the study area is known by analyzing wireline log, source rock geochemical data, drilling report, and well pressure data. The generating mechanism of overpressure in the study area was analyzed based on source rock geochemical data, wireline log, and Dutta plot. The result of the analysis shows that one well is in hydrostatic condition while three other wells are in overpressure condition. The overpressure in one well is caused by disequilibrium compaction (loading mechanism), and in two other wells are also caused by source rock maturation and clay diagenesis (nonloading mechanism). The Eaton Method was used to estimate pore pressure in overpressured wells. The Eaton exponent in the study area ranges from 1.1 - 2.6 for sonic log. The difference of top overpressure is influenced by sedimentation rate, lithologic variation, and well position.<p align="justify">