| Abstract |
While the exact number not known, roughly tens of thousands of abandoned oil fields exist globally. Most of these abandoned oil fields do not have an economic value and possess an environmental risk due to leaks from improperly abandoned wells. These fields contain considerable amounts of oil because an oil field is abandoned not when the oil is depleted but when the economic limit is reached. This study explores the idea; using In situ Combustion (ISC), an enhanced oil recovery method to improve oil production, to create Enhanced Geothermal Systems (EGS) within the abandoned reservoirs. In short, by air injection into a reservoir, the oil in place is oxidized to generate energy. The energy is stored within the reservoir matrix. The energy is extracted by injecting water and producing steam and electricity is generated from produced hot fluid likewise EGS. By converting oil fields into EGS, not only energy generation is possible but also potential environmental hazards are prevented as the oil will be combusted within the reservoir. The study is composed of two main parts: First, lab scale simulations were performed with CMG STARS with integration of combustion reactions. The key parameters for the success of the process were identified and criteria for propagating a steam zone behind the combustion front were determined. Second, based on lab scale simulations with kinetic reactions, an up-scaled model was built with pseudo reactions and field scale simulations were performed. Sustainability of high flow rates (at required temperatures) needed to support a commercial-sized power plant seems to be one of the major concerns regarding the process. Different well configurations were tested to meet the required high flow rates and options were explored to be able to design a feasible process. |