Publications

A rock physics study conducted on twenty two (22) wells from the deep water Kutei Basin (East Kalimantan – Indonesia) was carried out to analyse the elastic properties on a basin-scale level and generate stochastic AVO modelling for fluid and lithology prediction. The creation of an AVO reference model based on measured data is deemed of great importance for prospect generation de-risking of the field. The methodology consisted in the execution of two phases. The first phase involved the analysis and quality control of the well-log elastic properties distribution, the identification of six litho-fluid classes (normal pressure shales, brine sands, oil sands, gas sands, overpressured shales and vulcanites) and fluid replacement modelling to create different fluid scenarios for the sands. Then, depth trend analysis was carried out well by well for each elastic property: density, P-wave velocity and S-wave velocity with variability and correlation analysis performed. The second phase relied on the use of Monte Carlo simulation to generate a large number of elastic properties realisations for each litho-fluid class and then calculate AVO intercept and gradient to be used for analysis. The study highlighted that the key factor driving the elastic behaviour is the burial depth. Modelling the elastic behaviour of “anomalous” lithologies (vulcanites and overpressured shales), which are also present in the basin, allowed an understanding of their theoretical impact on the capability to discriminate hydrocarbon bearing sands.