f Assessment of Uncertainties in Oil and Gas Reserves Estimations By Various Evaluation Methods

The ultimate target of all oil companies is to increase their income by producing oil and/or gas. The key parameter to produce oil/or gas is the investments, such as purchasing licenses, drilling wells and constructing production facilities. Companies program their investments to a particular field by analyzing the ultimate recovery from that field. In this study, two most-widely used reserves estimation methods, volumetric method and material balance method are applied to estimate the Gas Initially in Place (GIIP) in a TPAO gas field, Çayırdere Field. Meanwhile, the importance of probabilistic approach to reserves estimation is emphasized by showing the change in estimated values by producing time. In addition to estimate reserves in probabilistic fashion, analytic uncertainty propagation method (AUPM), a simple, yet quite accurate alternative uncertainty quantification method to the well known Monte Carlo method is used to assess the uncertainty in GIIP of Çayırdere Field and is discussed in detail.