PEMODELAN 3D FASIES DAN PERSEBARAN KUALITAS RESERVOIR BATUPASIR ‘MNH’, FORMASI MENGGALA LAPANGAN ‘PEMA’, CEKUNGAN SUMATRA TENGAH

MUHAMMAD BAGUS RAHARJO, Rahmadi Hidayat, S.T., M.Eng., Ph.D.; Ir. Jarot Setyowiyoto, M.Sc., Ph.D. IPU., ASEAN.Eng.

2026 | Skripsi | TEKNIK GEOLOGI

Lapangan “PEMA” merupakan lapangan minyak dan gas bumi yang terletak di Cekungan Sumatra Tengah. Penelitian ini dilakukan pada interval reservoir batupasir MNH yang merupakan anggota daripada Formasi Menggala dan merupakan zona reservoir hidrokarbon pada Lapangan “PEMA”. Penelitian ini menggunakan 103 data log sumur, data batuan inti dari 3 sumur, peta struktur bawah permukaan, biostratigrafi, data uji tekanan, data uji produksi, dan completion history. Analisis yang dilakukan berupa analisis dan korelasi biostratigrafi, analisis lithofasies batuan inti, korelasi sumur, analisis fasies dan persebarannya, validasi data dinamik (tekanan dan produksi), analisis kontak fluida, pemodelan fasies, pemodelan variogram, pemodelan volume serpih, pemodelan porositas efektif, pemodelan permeabilitas, dan persebaran kualitas reservoir. Analisis fasies dan lingkungan pengendapan menghasilkan bahwa pada reservoir batupasir MNH terdapat 7 fasies, yaitu proximal tidal bar axis, proximal tidal bar off axis, proximal tidal bar margin, proximal tidal bar batupasir kasar, proximal tidal bar batupasir sedang - halus, amalgamated tidal bar, dan tidal bar flat, yang kemudian diinterpretasi pada lingkungan pengendapan tide-dominated estuary dengan asosiasi fasies tidal sand bar complex. Analisis dan perhitungan petrofisika menghasilkan nilai ambang batas untuk zona pay, yaitu VSH 0.65, PHIE 0,1, dan SWE 0,62. Pemodelan properti petrofisika dan persebaran kualitas resevoir menghasilkan nilai rata-rata properti reservoir batupasir MNH, yaitu nilai volume serpih (VSH) 0,3752, porositas efektif (PHIE) 0,1670, permeabilitas (PERM) 884,9101 mD. Fasies yang memiliki kualitas terbaik pada reservoir batupasir MNH yaitu proximal tidal bar axis dan proximal tidal bar off axis. 

The "PEMA" field is an oil and gas field located in the Central Sumatra Basin. This research was conducted on the MNH sandstone reservoir interval, which is a member of the Menggala Formation and represents the hydrocarbon reservoir zone in the "PEMA" Field. This study utilized 103 well log data points, core data from 3 wells, subsurface structural maps, biostratigraphy, pressure test data, production test data, and completion history. The analyses performed included biostratigraphic analysis and correlation, core lithofacies analysis, well correlation, facies analysis and distribution, dynamic data validation (pressure and production), fluid contact analysis, facies modeling, variogram modeling, shale volume modeling, effective porosity modeling, permeability modeling, and reservoir quality distribution. Facies analysis and depositional environment interpretation revealed seven facies within the MNH sandstone reservoir: proximal tidal bar axis, proximal tidal bar off axis, proximal tidal bar margin, proximal tidal bar coarse sandstone, proximal tidal bar fine sandstone, amalgamated tidal bar, and tidal bar flat. These were interpreted as a tide-dominated estuary depositional environment with a tidal sand bar complex facies association. Petrophysical analysis and calculations yielded threshold values for the pay zone: VSH (shale volume) of 0.65, PHIE (effective porosity) of 0.1. Petrophysical property modeling and reservoir quality distribution resulted in average values for the MNH sandstone reservoir properties: shale volume (VSH) of 0.3752, effective porosity (PHIE) of 0.1670, and permeability (PERM) of 884.9101 mD. The facies with the best quality in the MNH sandstone reservoir are the proximal tidal bar axis and proximal tidal bar off axis.

Kata Kunci : facies, depositional environment, facies modeling, reservoir property modeling, reservoir quality distribution