Reservoir Facies of Nahr Umr Formation in Luhais Oilfield, Southern Iraq

The current study includes characterization of clastic reservoirs and depositional environments of Nahr Umr Formation in four wells are (Lu-2, Lu-3, Lu-5 and Lu-8) of Luhais Oilfield. Depositional environments of Nahr Umr Formation are represented by, offshore, shoreface, delta (including mouthbar and distributary channel fill), tidal flat, swamp, fluvial channel and floodplain. Reservoir characterization and facies analyses are used to divide the Nahr Umr formation into upper shale member and lower sand member. Upper shale member characterized by low reservoir properties related to high shale content and high water saturation. The sand member divided into ten units are, A, B, C, D, E, F, G, H, I and J. Units A, C, E, G and I are sandstone units and the other are shale units. Units C and E are considered reservoir units in most of studied wells related to large thickness, low shale content and low water saturation and represented by distributary channel fill facies with high effective porosity. Reservoir properties studied are made by using the porosity and permeability (poroperm) readings for studies wells to find the relationships between porosity and permeability in reservoir and non-reservoir units.