Facies Associations Modeling Based on Geological and Petrophysical Data (Wire Line Logs) in the South Pars Gas Field

Upper Dalan formation, is a complex of carbonate reefs-evaporite, and Kangan with dominant lithology of limestone and dolomite is associated with anhydrite layers; Permo-Triassic succession of the South Pars gas field hosts the largest none-associated gas reservoir in the world located in the offshore of the Persian Gulf between Iran and Qatar. The geometry and distribution of high energy facies (shoal facies) are the main constituents of field reservoir quality, which is controlled with sedimentary environment. This study deals with the assessment of geological facies and their relation with petrophysical properties in incorporation with wire line logs to propagate the reservoir schemes. Core and petrographic analysis were carried out with the aim of recognizing the distribution of sedimentary facies and facies associations. Twelve microfacies were categorized into 4 major facies associations: tidal flat, lagoon, shoal, and open marine. The reservoir quality of facies associations was evaluated based on core porosity and permeability. In un-cored wells, facies associations were predicted as logfacies based on wire line logs by using intelligent neural networks. The sequence stratigraphic framework in the field was used to correlate facies in a two dimensional model. The 3D distribution of facies associations is assessed as logfacies by geostatistical modeling and sequential indicator simulation.