Litho-Fluid Characterisation Of Fluvio-Deltaic Gas Reservoirs Through Ava Deterministic And Stochastic Seismic Inversion

A state-of-the-art Amplitude-versus-Angle (AVA) inversion methodology is described in this case study to quantitatively integrate partially-stacked seismic data, well logs, geologic data and geostatistical information. Deterministic and stochastic inversion algorithms are used to characterise Intra-Triassic Mungaroo gas reservoirs located in the Carnarvon Basin, Western Australia. AVA deterministic and stochastic inversions, which combine the advantages of AVA analysis with those of seismic inversion, have provided quantitative information about the lateral continuity of the Fluvio-Deltaic reservoirs as well as the delineation of the gas reservoirs, based on the interpretation of inverted elastic properties and lithology and fluid-sensitive modulus attributes. AVA stochastic inversion provides more realistic and higher-resolution results than those obtained from analogous deterministic techniques and allows for uncertainty analysis. The quantitative use of rock/fluid information through AVA seismic data, coupled with the co-simulation of elastic/petrophysical properties, provides accurate 3D models of engineering properties such as porosity, volume of shale, and water saturation which can be directly used for static model building.