Reservoir Characterization by AVO Analysis: A Case Study of Penyu Basin, Malaysia

Abstract

Amplitude variations with offset (AVO) method are applied in predicting hydrocarbon by interpreting the anomalies in terms of lithology and pore fluids using the AVO cross-plot of intercept, A, and gradient, B. The study was carried out and tested in the previously problematic field such as thick sand with non-commercial discovery in Penyu Basin, Malaysia. With limited prospect evaluation conducted in this basin, we aim to provide evidence of potential hydrocarbon accumulation exists in this region for further exploration development. The AVO response of the anomalies detected first executed in locating the potential hydrocarbon prospect before predicting shear wave velocity using the Greenberg-Castagna and Castagna equations. A statistical wavelet was then correlated with seismic data to optimize the depth-time conversion for synthetic derivation prior to fluid replacement modelling and Gassmann’s equations. It is concluded that the AVO class II anomalies on both seismic and synthetic seismogram generated by AVO modelling agreed on the presence of oil in the reservoir. The AVO and seismic attributes suggested that there are potential hydrocarbon prospects in the Penyu basin based on the interpretation of structural traps of faulted anticline and fault.