The Diagenesis Study Attributed to Depositional Environment in Determining Potential Porosity in Talang Akar Formation, South Sumatera Basin

The Southern Sumatera Basin is a productive hydrocarbon basin and makes it very interesting to study. The basin is infilled with carbonate and siliciclastic Talang Akar sedimentary rocks as a main potential reservoir in the area. This paper focuses on studying the diagenetic process linkage with the facies sedimentation to identify the characteristic porosity of the siliciclastic Talang Akar Formation. The research used well data consisting of log data of 3 wells and a thin section of selection well section, further it applied the concept of sequential stratigraphy to develop a depositional environment accurately. The result of the study shows that the siliciclastic Talang Akar reservoir consists of argillaceous sandstone and calcareous sandstone, both of them deposited in the delta front which is highly affected by fluctuation in sea level (eustacy). The main target porosity in the study area is the vuggy secondary porosity that occurs intensively in the calcareous sandstone. Whereas matrix recrystallized to illite and also sericite are widespread in a certain depth of the argilliceous sandstone and it must be potential to microporosity. There is a significant relationship between the abundance of vuggy secondary porosity in calcareous sandstone with Sequence Boundary (SB) as reflected in 1090 m and 1100 depth.