Uncertainty quantification by using stochastic approach in pore volume calculation for geothermal reservoir

Gürel, Emrah
This study will present the application of a stochastic approach and experimental design techniques to a geologic system in order to quantify the uncertainty of pore volume estimations for a liquid dominated high temperature geothermal reservoir. The pore volume is a key element when defining the total resource available in the field. Alasehir geothermal reservoir pore volume uncertainty has been assessed. The uncertainties being addressed include geometry (top of reservoir and base of reservoir), reservoir continuity and porosity. Porosity of reservoir rocks (marble and schist) that are producing formations of Alasehir reservoir has been calculated using fractal analysis method. Thickness of the reservoir is obtained using drilling logs, seismic and resistivity data interpretations. Areal extent of the reservoir is obtained using reservoir temperature data obtained from static temperature logs of 25 previously drilled wells. Uncertainties were firstly characterized by standard deviations and then evaluated from the statistical distribution using Monte Carlo simulations. Placket and Burman design is performed with Minitab software using the significance at 95% confidence level and to identify the sensitivity of parameters on pore volume calculation. It has been found that porosity followed by the thickness and the area is most uncertain parameters that effect pore volume.