Cluster Analysis of Petrophysical and Geological Parameters for Separating the Electrofacies of a Gas Carbonate Reservoir Sequence

Abstract

Assessing reservoir properties and knowing the relationship between different reservoir parameters can significantly help to plan for production from a reservoir. In this study, which was carried out on the gas reservoir of the Triassic Dahram Group at the South Pars Gas Field, in southern Iran, petrophysical parameters such as porosity, shale volume, saturation of water and hydrocarbon, as well as amount of different minerals in the reservoir sequence, were first calculated using the probabilistic evaluation method. In the second step, for the separation of the sequential electrofacies, the multi-resolution chart-based clustering method was used resulting in recognition of five electrofacies with different reservoir geological properties. The results obtained from the first and second steps showed that the no. 5 electrofacies (EF-5), which has clean lime lithology and has the lowest water saturation, good porosity and high gas volume, was considered as the best reservoir facies in the studied sequence. Therefore, by separation of electrofacies, a suitable relationship can be found between different geological facies and petrophysical parameters of the reservoir.