To study the fractured basement by using the seismic data, we need to pay attention to from the starting acquisition to the completing processing and apply of convenient and optimal parameters as well as modern technology must be considered.
Seismic information inside fractured granite basement is one of the most important and valuable data for the fractured basement reservoir study. In order to get this seismic information, it is a great challenge in the exploration and the production due to incorrect understanding of the fracture essence and processing approach.
As any other sedimentary environment, these are many reflections which appear on the surface between the fracture filling fluid inside the basement and the unaltered granite basement. For the basement reservoir, fractures are deeply and not horizontally distributed.
The amplitude, frequency and the reflection time length are seismic information of the seismic signal related to the specific fractures filling fluid in a granite basement. The seismic amplitude is a direct function of density and velocity. Anisotropy factor is a strong influence on the seismic data. In other words, anisotropy relates to fractures and the seismic amplitude. The frequency of the seismic wave is decreasing with depth and quality of geological image and resolution related to this parameter. The sensitive processing parameters have to be selected correctly. These information much be used together with the well data.
A conventional seismic processing approach can not provide inside a fractured basement information.
The 3D PSDM seismic data provides much better information to geological interpretation. Thanks to the data, the conception of structural and the fracture inside basement was changed.
Geological structural image and fractured in side basement were confirmed by many drilled exploration and production wells. These papers introduce a case study from seismic data for Bach Ho and Dragon fracture basement reservoirs.