Identifying reservoir electrofacies has an important role in determining hydrocarbon bearing intervals. In this study, electrofacies of the Kockatea Formation in the Perth Basin were determined via cluster analysis. In this method, distance data were initially calculated and then connected spatially by using a linkage function. The dendrogram function was used to extract the cluster tree for formations over the study area. Input logs were sonic log (DT), gamma ray log (GR), resistivity log (IND), and spontaneous potential (SP). A total of 30 reservoir electrofacies were identified within this formation. Integrated geochemical and petrophysics data showed that zones with electrofacies 3, 4, 9, and 10 have potential for shale gas production. In addition, the results showed that cluster analysis is a precise, rapid, and cost-effective method for zoning reservoirs and determining electrofacies in hydrocarbon reservoirs.

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Reservoir characterization is one of the key stages in oil and gas exploration, appraisal, development, and optimal production. During the exploration phase, core analysis and well logging are basic information obtained after the pay zone identification. This study aims to integrate the concept of electrofacies (EFs) with hydraulic flow units (HFUs) to effectively characterize Permo–Triassic carbonate formations at the Kangan giant gas field in southwestern Iran. For this purpose, well log data collected from 10 drilled wellbores and 490 core data have been analyzed based on similar clusters and statistical features in which rock-type approaches were used in order to integrate petrophysical data with facies. In particular, we used a multi-resolution graph-based clustering (MRGC) method to determine EFs and the probability plot method, histogram analysis, and the plot of reservoir quality index versus the normalized porosity to identify HFUs. Based on the data, five electrofacies and six HFUs were identified. To establish a good connection between the electrofacies and the pay zones, we analyzed wells’ cross sections to compare lithology, production potential in each zone, rock type, and amount of shale and eventually to adapt facies to flow units and determine the best quality reservoir zone. The main difference between this work and other studies in the literature is adopting a systematic approach based on integrating the geology (via EFs analysis) and engineering examination (via HFUs) to accurately characterize the hydrocarbon-bearing formations. The results of this study help in rapid and cost-effective carbonate reservoir characterization by combining electrofacies clustering and HFU analysis based on core and log data, which are available and routine information in all oil/gas fields. This, in turn, assists in developing the field, using more appropriate production and EOR scenarios, and even locating proper perforation sites.

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Zagros Basin is a very important hydrocarbon region in the Iran and World. One of the major reservoirs in this basin is the Lower Cretaceous Dariyan Formation. Based on petrographic studies, 9 microfacies were determined and interpreted as related to lagoon, barrier island and open marine environments. Facies associations show deposition in a carbonate ramp. Sequence stratigraphy studies show two sequences, each one with a transgressive system tract, marked by open marine microfacies, and then a retrogradational highstand, marked by barrier and lagoonal facies. Paleogeography and sequence stratigraphy studies of this formation and correlation of it with other sections may provide useful information about reservoir characterizations.