ÇAĞRILI KONUŞMALAR / KEYNOTES Invited Speeches ... - TPJD

Quantification of Uncertainty in Petroleum, Natural Gas and Geothermal
Engineering Applications
Ömer İnanç Türeyen, Mustafa Onur
İstanbul Technical University, Faculty of Mines, Department of Petroleum and Natural Gas
Engineering, İstanbul
The ultimate goal in any petroleum, natural gas or geothermal reservoir engineering study
is to make performance predictions. Some of the variables to be predicted are pressures,
recoverable oil, recoverable gas, recoverable heat from geothermal reservoirs, water cut, gas
oil ratio and etc. Making predictions is vital for the economical exploitation of the resources.
What is more important is the quantification of the uncertainty related to the predictions.
Uncertainty in all future predictions is inherent due to (i) measurement errors or noise in the
data, (ii) lack of data, (iii) modeling errors, (iv) span of the available observed data and (v) the
non-linear relationship between the data and the model response. In this study we present an
overview of the methodologies used to quantify the uncertainty in future predictions from oil,
gas and geothermal reservoirs. We will present synthetic applications of various techniques for
quantifying the uncertainty of gas in place for gas reservoirs, of heat in place for geothermal
reservoirs, of water cut from oil wells and of pressure and temperature predictions using
tank models for geothermal reservoirs. The techniques discussed will cover the Monte Carlo
method, the analytical uncertainty propagation equation, the gradual deformation method, the
randomized maximum likelihood method and the more recent Ensemble Kalman Filter method.
Keywords: Reservoir engineering, data integration, history matching
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