--> Quantification of Rock Properties in the Reservoir Rock Units of South Lake Albert Basin, Albertine Rift, Western Uganda

2020 AAPG Hedberg Conference:
Geology and Hydrocarbon Potential of the Circum-Gulf of Mexico Pre-salt Section

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Quantification of Rock Properties in the Reservoir Rock Units of South Lake Albert Basin, Albertine Rift, Western Uganda

Abstract

The study area in South Lake Albert Basin covers the Kaiso-Tonya and Kingfisher areas. Kaiso Tonya consisted of four fields (Mputa, Nzizi, Waraga and Ngassa) which have varying reservoir geology. The Mputa and Nzizi fields lay within the Sebugoro-Kaiso Relay Play which was dominantly a fluvial-lacustrine-deltaic depositional environment. Waraga Field lay at the northern tip of the Kaiso-Tonya Relay Zone and reservoir sediments of Waraga Field were deposited in a dominantly fluvial-lacustrine-alluvial fan depositional environment. Ngassa Field is a down-thrown fault block sealed to the southeast by the main lake bounding, large offset rift fault and prospective volumes of Ngassa rely on a second northwest-southeast trending fault. Petrel 2016.3 and Techlog 2015 software were used in construction of the 3D reservoir property model using 3D seismic and well data (wire line logs). Faults that were interpreted on 3D seismic volume and horizons’ interpretations were used as input in generating structural maps, generation of the structural maps involved the use of convergent interpolation algorithm using seismic lines with high density. Thus, a velocity model was created using structural maps (surfaces) as inputs and this velocity model was used for depth conversion. Horizon and fault interpretations were depth converted using the velocity model and then used in structural modeling. Thus, property models for effective porosity, total porosity, permeability, and Vshale were generated from their respective upscaled logs. From the constructed reservoir model, property maps (porosity, permeability and Vshale) were extracted to assist in evaluating reservoir properties and values of porosity, permeability, Vshale helped to determine quality of the different reservoir rock units.