Carbonate Reservoir Characterization Based on Rock Type Analysis in Minahaki Formation and Tomori Formation, "HK" Field, Banggai Basin

Abstract

The research area is located in the Banggai Basin, Central Sulawesi, which part of the Eastern Arm of Sulawesi Island that originated from the collision between Banggai - Sula Microcontinent and West Arm Volcanic Arc from Sulawesi Island. This research has reservoir target in Minahaki Formation and Tomori Formation those are carbonate rocks. The problem limitation of this research is to characterize carbonate reservoir based on the distribution of rock types. The intention of this research is to analyze carbonate reservoirs with petrophysical properties and analyze reservoir characterization based on rock type distribution, while the purpose is determine the petrophysical property values of the Minahaki Formation and Tomori Formation, then determine the distribution of rock types for characterizing the reservoir rocks. The research methods begin with literature study, data collection, and data analysis. The results of the petrophysical analysis and pay zone in Minahaki Formation obtained an average: net pay thickness is 359.5 feet – 398.5 feet, vshale 23.55% - 34.48%, PHIT 13.33% - 22.84%, PHIE 9.9% - 16.89%, Sw 61.23% - 76.95%, and permeability 610.5 mD – 1360.1 mD. Meanwhile, Tomori Formation obtained an average: net pay thickness is 52.5 feet – 679 feet, vshale 16.53% - 34.7%, PHIT 3.5% - 7.87%, PHIE 2.77% - 6.09%, Sw 26.01% - 42.97%, and permeability 39 mD – 161.9 mD. There are six rock type distribution in the research area those are rock type 1 is ≤ 0.245 micrometers, rock type 2 is 0.314 – 0.48 micrometers, rock type 3 is 0.5 – 0.965 micrometers, rock type 4 is 1.04 – 2.35 micrometers, rock type 5 is 2.36 – 15.08 micrometers, and rock type 6 is 19.66 – 78.82 micrometers.