Publications

Although only contributes few to the total oil and gas production, fractured basement reservoir is one of the important unconventional reservoirs in Indonesia. It was estimated that the gas reserve in basement in South Sumatra is about 6 TCF (trillion cubic feet). Most of the existing geophysical methods is not intended to explore events within the basement. In fact, majority of basement reservoir discovery was coincident. Despite its significant contribution to Indonesia’s gas production, the exploration success story in the fractured basement play is still poorly documented. The challenges and difficulties in their characterization are higher than the conventional reservoir. This study presents an integrated geological and geophysical approach to improve the outcome of seismic imaging of the fractured basement reservoir. A comprehensive geological study and geophysical modelling were conducted to provide an efficient strategy for designing an optimum seismic survey in imaging the fractures within the basement. Both surface and subsurface data were thoroughly analyzed to yield a reliable representation of the subsurface fracture model at basement level. Outcrop sample analysis combined with aerial remote sensing analysis were performed as input to digital outcrop modelling. The modelling was intended to provide information about fracture orientation, length, and density. This will provide a fracture property in the surface which is related to the fracture properties in subsurface. The resulting fracture properties was then used as an input to evaluate the seismic wave response during its propagation in the reservoir. Seismic modelling has been done using a 2D finite-difference full wavefield approach in a Graphics Processing Unit (GPU) accelerated computing system. We observe how fracture properties affect the propagating seismic wavefield. Wave scattering is observed more prominently around the fracture tip when the fracture plane is orthogonal to wavefield direction.