THREE DIMENSIONAL GEOMECHANICAL MODELING FOR UNCONVENTIONAL HYDROCARBON DEVELOPMENT TANJUNG FORMATION, BARITO BASIN SOUTH KALIMANTAN

• Main Author: Ridha Falkhan Barizi, Antu
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/84336
• Institution: Institut Teknologi Bandung

The unconventional hydrocarbon resources potential in Indonesia is immense. This potential is spread across several basins throughout Indonesia, including the Barito Basin. The Tanjung Formation has long been recognized as a hydrocarbon source rock in the Barito Basin. The extraction of unconventional oil and gas resources requires special treatment due to the reservoir rock being shale, which also serves as the source rock and has very low permeability. Increasing permeability is typically achieved through hydraulic fracturing, which necessitates the characterization of in-situ stress. One-dimensional geomechanical analysis involves estimating in-situ stress magnitudes, rock elastic properties, and rock strength parameters through core analysis and wireline log calculations. Subsequently, three-dimensional geomechanical modeling is performed to observe the distribution of stress and the spatial variation of rock mechanical properties. The distribution of rock mechanical properties and in-situ stress in three-dimensional modeling is more complex because these properties tend not to have distribution trends like physical properties (such as VShale) that follow depositional trends. In this study, the distribution of mechanical properties in three-dimensional modeling was carried out using a seismic-driven approach with the seismic resampling method. This approach involves seismic inversion processes to correlate seismic attributes with rock mechanical properties. The pore pressure prediction in one-dimensional geomechanical analysis indicate low to normal pressure conditions (0.382-0.451 psi/ft), while the vertical stress gradient is 1.028 psi/ft. The average Young's Modulus for shale lithology is 15.44 GPa and for sandstone is 21.06 GPa, with an average Poisson's Ratio of 0.307. The rock strength of the Tanjung Formation has an average value of 86.6 MPa for shale lithology and 87.7 MPa for sandstone lithology, with an average friction angle of 33.2°. The estimated horizontal stress shows an average ????????????????? gradient of 0.975 psi/ft and an average rediction gradienpt of 2.001 psi/ft. The present-day stress regime in the study area varies from reverse faulting (????????????????????> ????????????????? > ????????) at shallow depths (0 – ±2000 ft) to strike-slip faulting (???????????????????? > ???????? > ?????????????????) at greater depths (±2000 – ±5000 ft). The accuracy evaluation of the three-dimensional model against well data, both visually and statistically, shows a good level of fit and accuracy. This indicates that modeling using a seismic driven approach (with the seismic resampling method) has successfully distributed the rock mechanical properties and in-situ stress optimally. Interval TFA1 is identified as the best target interval for hydraulic fracturing because it has the highest Young's Modulus and the lowest Poisson's Ratio compared to other intervals in the Tanjung Formation. The recommended orientation for horizontal drilling is N330° - 350°E or parallel to the orientation of ?????????????????.