Analytical modeling of effect of volume of shale different calculation methods on reservoir petrophysical parameters

The effect of volume of shale different calculation methods on reservoir petrophysical parameters was analytically modelled and evaluated using ‘PETRARCAL.’ It is essential to characterize the hydrocarbon reservoir as precisely as possible in other to calculate petrophysical properties of interest in the region and to decide the most effective way of recovering as much of the hydrocarbon as economically possible and to rank the reservoir involved in the integration of vast amount of data needed in reservoir characterization. A petrophysical parameter calculator ‘PETRARCAL’ was programmed. The graphic user interface was designed using MATLAB to calculate the reservoir petrophysical properties such as gamma-ray- Index, the volume of shale using different calculation methods, and other volumes of shale dependent petrophysical parameters such as permeability, porosity, hydrocarbon saturation, water saturation, and hydrocarbon pore volume were mathematically coded in MATLAB. The plot of all the computed volume of shale versus gamma-ray index for different mathematical relationships Showed a similarity between tertiary, consolidated, and Steiber volume of Shale computational methods, trending exponential to almost linear curve. However, the Clavier method was completely different, with a decrease hyperbola curve. From the wireline log, with GR_log of 52, GR_Min of 19, and GRmax of 81, the computed IGR is 0.53228. The resulting shale volume is 0.360, 0.242, and 2.319 0.275 for Dresser consolidated, Dresser tertiary, Clavier, and Stieber computational methods. Density corrected porosity (ϕ_DC) values from the wireline were determined to be 69.8%, 73.7%, 4.5%, and 75.6% for dresser consolidated, dresser tertiary Clavier, and Steiber methods, respectively. Permeability was computed to be 10,778, 16,858, 0.0021, and 14,912 for consolidated, tertiary,Clavier, and Stieber methods, respectively. Arbitrary use of just any of the volume of shale calculation methods will be an abuse of its application without understanding the environment of study. PETPARCAL can be used as a petrophysical parameter calculator for quick reservoir evaluation for petrophysicists and geoscientists. The efficacy of MATLAB application in geoscience modeling is excellent as it has been applied in this study.