THE ANALYSIS OF OVERPRESSURE CHARACTERISTICS USING WIRE LINE LOG DATA IN MUARA FIELD, UPPER KUTAI SUB-BASIN, CENTRAL KALIMANTAN

• Main Author: Widiyarti, Melly
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69675
• Institution: Institut Teknologi Bandung

The Muara Field is a gas-producing field in the Muara Teweh area which was discovered in 1982. The study area is located in the Upper Kutai Basin which is divided into four formations, i.e. Tanjung Atas, Berai, Bongan, and Warukin. The study is performed in these four formations which are Late Eocene - Middle Miocene age. During the drilling, several obstacles were found, such as the occurance of connection gas, sloughing shale, background gas and stuck pipe. The drillings problems may indicate the presence of overpressure zones. Overpressure that is not estimated properly, can result in financial and technical losses that have a large enough impact when drilling is carried out. The purpose of this study is to analyze the characteristics of overpressure, estimate pore pressure, determine the top of overpressure, determine the mechanism of overpressure generation, and analyze the relationship between the geological conditions of the study area with the presence of overpressure. Data processing was carried out in four wells using wire line log data, mud pressure, pressure test data, temperature data, drilling reports, and vitrinite reflectance data. The condition of the study area is used as a reference in estimating the pore pressure. Based on the results of the analysis, it was found that the four wells had an overpressure zone. The overpressure zone is reached from a depth of 1950 m. The results of the analysis show that the four wells have hydrostatic pressure and overpressure conditions. The generating mechanism in the overpressure zone is generally influenced by loading and nonloading with an estimated pore pressure of 2800 - 6800 psi. The loading mechanism is caused by the high sedimentation rate in the Warukin Formation due to the uplift of the Kuching Highlands and Central Kalimantan, thus, there is a change in the depositional environment into a delta. In addition, the influence of the nonloading mechanism on each well in the study area can be caused by hydrocarbon maturity and clay mineral diagenesis