Uncertainty Analyses for Thermal Development in Heavy Oil Fields

The main purpose of this work is to get an insight into thermal development strategies to be applied in an extra-heavy oil field. The goals of this study are: to study the feasibility of thermal EOR techniques; to perform a risk analysis highlighting the main uncertainties on reservoir development. Firstly, a general overview of the field is given. Steamflooding has been thoroughly investigated, by optimizing operating parameters and evaluating their effect on oil recovery and steam-oil-ratio (SOR). Similar sensitivity analyses have been performed for the down-hole electrical heating technique, focusing particularly on power input, and evaluating the propagation of heat in the reservoir. Risk analyses have been then performed in order to highlight the main uncertainties affecting the field development, in cold production as well as in steamflooding and electrical heating. Risk analysis was carried out by applying both the classic Monte Carlo workflow and the Experimental Design and Response Surface Modelling. This methodology becomes advisable when simulation runtime is excessive and a classic Monte Carlo workflow is too expensive. The last part of the paper covers basic pseudo-economic analysis to assist in the comparison between cost-benefits of steamflooding and electrical heating. The main outcomes of this work are the following: steamflooding proved to be an effective way to improve oil recovery, although for pessimistic scenarios (i.e. very high viscosity) its convenience should be properly evaluated; electrical heating can cheaply provide additional oil recovery. The performed analysis has highlighted the risk and the opportunities of the two thermal recovery techniques.