Permeability Determination in Fractured & Non-Fractured Carbonate Reservoir; Using Innovative Multi Property Threshold Analysis Approach of Basic Log Data

Abstract

Abstract It's been long years of trials worldwide to find the relation between permeability and any other reservoir property or log and/or relation with combination of them. There have been even neural network, fuzzy logic and equation solver software modules used to enable extracting and finding probable sophisticated equation for permeability determination from log data, in a way replicating Archie's Equation for water saturation determination, however; it's important to keep in mind that core analysis were unable to provide proper reservoir water saturation due to coring operation deficiency in preserving core fluid from the time of coring until reaching surface and labs unless highly cost pressure coring was conducted. While core plug permeability measurements provide solid reference of permeability; in the other hand, if water saturation determination from logs is wrong no one can easily challenge it and proves opposite. Here, in this paper a new analysis approach is innovated and detailed, as the analysis did not look for one relationship between permeability across all geological layers and specific log data like previous approaches; instead, the new approach is finding multi relations between permeability variations across each layer and several log data types until finding the suitable log or logs that are providing adequate relation. As we found that each reservoir layer permeability range responds to different log data types more sound and obvious than other log data types, in a way reflecting the domination reasons for permeability ranges whether they are due to fracture or matrix or any other structural, stratigraphic, deposition or digenetic effects. This technique is utilized successfully in three different reservoirs; fractured limestone, non-fractured heterogeneous limestone and dolomitized-limestone.