Reservoir Property Prediction Using Well Logs and Attribute Maps Generated from 3D Seismic Data for Reservoir Characterisation

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JULY, 2016
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This research sought to determine the properties of a reservoir in the Western Tano Basin using well logs and attribute maps generated from 3D seismic data, in order to counter the relatively limited vertical resolution that comes with using only seismic data to characterise reservoirs. A network of four horizons (The Seabed, Top Upper Reservoir, Middle Shale and Base of Reservoir) were identified and mapped. Seismic data was used to identify the lithology and structure, and contour mapping of the horizons revealed the trapping systems in each layer. Amplitude extraction was performed to confirm the presence of the reservoir, and attribute mapping was used to generate the architectural elements which describe the location and distribution of the sand packages in the reservoir. Two well-containing zones (UP and LP) were selected as areas of interest due to the sand distribution density and availability of sufficient log data to corroborate the assumptions made. Wireline petrophysical parameters were extracted from log data within the intervals of investigation and used to calculate petrophysical properties. The result depicted very good porosity (21.2 & 20%), permeability (408.2 & 182.9 mD), oil saturation (88.2 & 85.2%) and original oil in place (104.56729 & 388.055 x 106 bbl/STB) values for the upper and lower intervals respectively. Comparing both intervals, the lower interval proved more productive and could be the reason for the presence of two wells in close proximity to each other in that area. According to the literature, the petrophysical values compared favourably to those of commercially exploitable reservoirs. This research therefore provides an excellent method for the integration of log data, attribute maps and 3D volume seismic data to determine reservoir properties with increased quality and accuracy, due to the added improvement of enhanced vertical resolution.
A Thesis Submitted to the Department of Physics, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements for the degree of Master of Philosophy in Geophysics,