Determination of Reservoir Rock Type in Sarvak Reservoir of an Iranian Oilfield

Integrated reservoir rock typing in carbonate reservoirs is a very significant step in reservoir modeling. The key purpose of this study is the determination of integrated rock types in Sarvak Formation of an Iranian oilfield. In this study, electrofacies (EFAC) analysis of Sarvak reservoir was done in detail to determine the reservoir quality and determine rock types of the Sarvak Formation in the studied field. The core data and conventional petrophysical logs were used for rock typing. Some petrophysical logs such as porosity, sonic, neutron, density, and PEF (Photo electric factor) were used as input data for electrofacies analysis. Multi-Resolution Graph-Based Clustering (MRGC) was used among six different approaches resulting four electrofacies after merging the similar clusters. EFAC-1 has the lowest and EFAC-4 has the highest porosity. In addition, based on Winland and Amaefule approaches, three rock types were determined using core data (porosity and permeability). As a result, three rock types were determined which rock type-1 has the smallest pore-throat size and FZI (flow zone indicator) while the rock type-3 has the highest ones. The correlation coefficient between porosity and permeability in each rock type is more than 80%. Rock type 1 mostly composed of EFAC-1 and EFAC-2, while the rock types 2 and 3 share mostly the EFACs 1, 3 and 4.