CARBONATE ROCKS GROUPING USING CRITICAL POROSITY APPROACH IN MIOCENE ROCKS, BANGGAI BASIN Sigit Rahmawan1*, Syamsul Irham1, Asri Nugrahanti1 , Firman Herdiansyah2, Samsol1, Suryo Prakoso3, Muhammad Burhannudinnur2, Djunaedi Agus Wibowo1, Hari Karyadi Oetomo1, Teddy Irano4, Thalia Ribka Marinada1
1Teknik Perminyakan,Universitas Trisakti, Jakarta, Indonesia
2Teknik Geologi, Universitas Trisakti, Jakarta, Indonesia
3Magister Teknik Perminyakan, Universitas Trisakti, Indonesia
4Exploration, JOB-Pertamina-Medco E&P Tomori Sulawesi, Jakarta, Indonesia
Abstract
Reservoir is the trapped underground tank of hydrocarbon fluid with heterogeneity of physical rock properties. The characteristics of rock heterogeneity significantly influence the rock^s ability to flow hydrocarbon fluid. Several methods have been developed to classify the heterogeneity of reservoir rocks, such as the Amaful, Permadi and Wibowo methods- among others. These methods are developed based on laboratory experiments using sandstone rocks- although in some studies, they are also frequently employed in categorizing carbonate reservoir rocks. However, these commonly used methods still face challenges in rock classification when actual rock samples are unavailable. In this study, the classification of carbonate reservoir rock is conducted using a Critical Porosity approach, and comparing with the Permadi and Wibowo method of the hydraulic flow unit classification method. The data utilized in this study consists of rock samples from the Miocene era of the Banggai Basin. This study reveals that using the Wibowo and Permadi method, ten rock classification is obtained, whereas employing the critical porosity approach resulting in six rock classification. Both methods demonstrate a correlation between rock pore structure and rock geometry- where rocks categorized under rock type #10 in the Wibowo and Permadi method, and rock type #6 in this study critical porosity method exhibit the smallest pore geometry values as compared to other rock types. Each rock classification signifies the rock^s fluid flow capability, with rocks categorized under rock type #1 indicating better fluid flow capability as they possess finer geometries.
