RESERVOIR CHARACTERIZATION AND RESERVE CALCULATION AT SOKA FIELD, MUDA FORMATION, EAST NATUNA BASIN

• Main Author: Verdinov Simanjuntak, Marchel
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/63765
• Institution: Institut Teknologi Bandung

Soka Field is a gas field located in eastern part of East Natuna Basin. This study conducted within SB1 – SB3 interval of Pliocene – Pleistocene age in Muda Formation. This study aims to understanding Soka Field’s geological configuration especially in study’s interval, identifying facies, facies association, and depositional environment of study’s interval, determining petrophysics property value in every parasequence of study’s interval, and estimating reservoir hydrocarbon in-place of Soka Field. Data used in this study came from four wells (MS-1, MS-2, MS-3, and MS-4) consists of wireline logs, well cutting descriptions, and three dimension that covers all wells. Seismic of study’s area shows several faults of normal faults with northeast – southwest relative direction. Facies and depositional environment yielded ten lithofacies consist of sandstone and claystone. Lithofacies analysis is then matched with electrofacies resulting SB1 – SB3 interval shows four facies association which are offshore transition, lower shoreface, middle shoreface, and upper shoreface deposited in shoreline environment. Sequence stratigraphy analysis shows study’s interval is dominated by coarsening upward parasequence, progradation and retrogradation parasequence set, lowstand system tract, transgressive system tract, and highstand system tract. Petrophysics analysis shows average property value of shale volumes, effective porosity, and water saturation of reservoir 1 is 0,264, 0,308, and 0,860 and reservoir 2 is 0,378, 0,267, and 0,658. Reservoir cut-off property values of shale volumes is at 0,355, effective porosity at 0,233, and water saturation at 0,900. Hydrocarbon in-place estimation results shows gas volumes of reservoir 1 is 70,93 BCF and reservoir 2 is 281,87 BCF with CO2 content in reservoir around 70-80 percent.