Carbonate Rock Type Matrix, the Ultimate Rock Properties Catalogue

The heterogeneity in carbonate rocks, made it hard for Geoscientists and Reservoir Engineers to define a universal classification methodology that is able to honour the critical reservoir static properties. Most classifications, like, lithofacies, capillarity and textural methods have based their rock typing concept on one or two static properties, then tried to find an analog to other static properties to cluster or group them, then worked to populate the rock types across the whole field. However, from field observations and experiences of utilizing these conventional techniques, it was obvious that they suffered from several gaps, like inability to have the properties analog consistent throughout the whole reservoir. Moreover, the groups or clusters have big dispersion that produced overlaps, and then theoretically they could not fully honour the physics and rock properties links. Therefore, in this study, rock typing is made to honour static properties all together through changing the classification concept to resolve the gaps of the traditional methodologies. The ultimate objective of all reservoir characterization and rock classification is to enable building geological and simulation models, with optimum honouring of rock properties. To achieve this objective, the established framework in this research is based on analyzing the effects of each of the rock properties on another and the value and impact that each can add to the models most critical parameters. By this technique, the gap of pore and pore-throat network is resolved through Multiple Properties Intersection. This Integrated Carbonate Rock Typing technique starts with capturing the heterogeneity of carbonate rock by generating matrix of core permeability, capillary pressure (end point, threshold pressure and Plateau), pore-throat size distribution and porosity. Then intersecting this matrix to construct weighted links between these properties and identify unique groups. Resulted classes are novel carbonate rock type classes that entered to feedback analysis node to explore and validate the logic of linked physics to tune the classes’ thresholds and assure no overlap between any of classification properties. Finally for utilizing this technique in non-cored wells, an analog with logging data is structured through novel permeability, capillary pressure and saturation function called the C-Function to be the replacement of the J-Function in Carbonate.