The Porous-Permeable Zones in Heterogeneous Carbonate Reservoirs: A Case Study from Amara Oilfield-Iraq

The understanding of carbonate rock heterogeneity under subsurface conditions are still in debate due to variation in mineral composition and changes in rock textures during/after diagenesis. However, several studied utilized the electrofacies code with using conventional set of logs to draw a detailed description of reservoir carbonate rocks. This study draws the precise modelling design for cretaceous carbonate reservoir characterization through micro- and -macro porous media and permeable zones, integrates the lithological variation with hundreds measurement of porosity/permeability values along two bore wells in Amara Oilfield. This study presents more than 1800 measurements with detailed description of lithological and reservoir characterization accordingly in Am1 and Am3 borewells form west to east, respectively. From west, the plugged samples obtained from Mishrif formations, while from east, the samples obtained from Khasib, Mishrif and Yamama formations. The porosity and permeability distribution in subsurface settings were divided into three porous-permeable zones in Am1 and AM3. The Am1 in the west shows a highest porous-permeable zone than Am3 in the east of Amara Oilfield. Therefore, the porous-permeable subsurface distribution and thier petrophysical mapping for different kinds of reservoirs reveal that the porosity and permeability measurements decreased from west to east, however, few fluctuations in increasing and decreasing of porosity and permeability values mostly controlled by involvement of diagenetic fluids which caused a heterogeneity in carbonate rocks.