The development of structural and heterogeneities of basement lithology in Pangea Block (PB) had a complex geological history. The application of conventional seismic method for naturally fracture mapping could not be directly conducted due to dimension of fracture that below the seismic resolution (sub-seismic). Therefore, integrated structural modeling and seismic attribute analysis used to predict the presence of fracture in the basement rocks. Fractures in basement rocks of PB was closely related to poly-phase deformation of basement involved tectonic. An integrated open fracture mapping using seismic attributes & FMI analysis revealed the major orientation of open fracture are NNE-SSW and NE-SW direction. Both of the direction are formed during extensional event in Late Eocene of South Sumatera Basin. The presence of the fractures associated with low amplitude and low similarity anomalies where intensively distributed around of the fault zone. Significant of DHI signature as reversal polarity and flat spots were observed in the internal part of BRF limestone, appropriate on the top of the NW basement high of PB. They suggest that the basement rocks below the interval may have a gas contain in the open fractures network. The field development strategy could be concerned in the fault system around of the basement high into cover the hanging wall blocks of the fault. FMI analysis resulting the average fracture porosity and density are <0.05% – 0.10% and 1,79-1,88 fractures/m, respectively whereas type of basement lithology, fracture spacing and aperture are the main control of the properties.
Author : A. Budiman, A. Priyono, A. Samodra, F. Mu’in, M. Latuconsina