Study of the dynamics of changes in porosity and permeability of fields in southern Iraq (Republic of Iraq)
Abstract
This study examines the porosity and permeability of productive carbonate reservoirs in the Nasiriyah oil field in southern Iraq. The authors compare the petrophysical properties of the reservoirs to identify the most favorable conditions for hydrocarbon production and to determine the most productive intervals. The results can help to optimize field development, justify priority drilling zones, and improve hydrocarbon recovery. This study has highly relevant to the oil and gas industry. It provides a basis for accurately assessing reservoir potential and guides effective field development planning. The study uses geophysical data from five production wells (NS-1–NS-5). Researchers applied comparative analysis of the spatial distribution of porosity permeability, and and net pay thickness within the productive reservoirs. Researchers applied statistical analysis and spatial interpolation methods. This approach enabled them to map key reservoir properties and delineate their lateral The results show a strong contrast between the two studied reservoirs. One reservoir has higher porosity (20–23%) and permeability (131–412 mD), whereas the second has lower values, with porosity of 12–15% and permeability of 2–6 mD. The spatial distribution of reservoir thickness and petrophysical properties has a dome-shaped pattern, with the highest values in the central part of the field. This pattern reflects the Cretaceous depositional conditions and subsequent diagenetic processes. The eastern part of the field shows poorer reservoir properties because of changes in lithology and deterioration of pore structure. The results confirm the high heterogeneity of the carbonate reservoirs and agree with published data from similar fields in southern Iraq. This study has important practical significance. The results can assist in identifying priority areas for new wells, optimizing field development systems, and enhancing geological and reservoir models.