Experimenting with Three Dimensional Reservoir Modeling Using Stochastic Simulation, a Case Study of an East African Oil Field

This paper presents a three dimensional geological reservoir model created using stochastic
simulation. The oil field presented is an East African oil field formed by a structural trap. Data analysis
and transformations were conducted on the properties before simulation. The variogram was used to
measure the spatial correlation of cell based facies modeling, and porosity and permeability modeling.
Two main lithologies were modelled using sequential indicator simulation, sand and shale. Sand had
a percentage of 26.8% and shale of 73.2%. There was a clear property distribution trend of sand and
shale from the southwest to the northeastern part of a reservoir. The distribution trend of the facies
resembled the proposed depositional model of the reservoir. Simulations show that average porosity
and permeability of the reservoir are about 20% and 1004 mD, respectively. Average water saturation
was 64%. STOIIP volume of 689.42 MMbbls was calculated. The results of simulation showed that
the south eastern part of the reservoir holds higher volumes of oil. In conclusion, the model gave a
better geological understanding of the geology of the area and can be used for decision making about
the future development of the reservoir, prediction performance and uncertainty analysis.