Depleted petroleum reservoirs are considered as the best underground facilities for carbon dioxide storage. The underground storage reservoirs are subject to the constant geothermal heat flux coming from the surrounded formations. Thus, there is an opportunity for further development of these projects for energy production if a sufficient temperature difference is reached between hot CO2 and cold ambient conditions. This is a great potential to satisfy raising national energy demand. The proposed design contains a single well energy conversion system that could eliminate building a traditional power plant at the surface facility and pumping geo-fluid to the surface. The method can be applied to the existing petroleum wells commissioned for an abandonment. Theoretically, up to 250 kW net power can be achieved from a single well at 125? reservoir temperature. This power unit has high efficiency of 15% and low Levelized Cost of Electricity (LCOE). Computed LCOE is in a good agreement with the references and shows competitive results with fossil fuel power plants. Additionally, the unit is compact and requires minimum surface facility footprint comparing with geothermal technologies. The combination of several wells into a power production unit opens an opportunity to generate up to 1 MW and more. All of the mentioned advantages lead to a quick payback of the investment. As a result, the new application can significantly reduce economic load associated with the CO2 pumping and storage.
The geological sequestration of CO2 in the depleted oil and gas reservoirs was mentioned in a literature as a smooth transition from the carbon dioxide flooding used for "releasing" the residual oil from the formation (Shaw& Bachu, 2002. Mamora & Seo, 2002, Li et al., 2006). Ideally, carbon dioxide can be pumped in a geological trap where it will remain for a long time. This bright idea, however, has many problems required to solve in order to succeed the project. One of them is an economic sustainability of the project. Capturing carbon dioxide in industry, pressurizing, transporting, and injecting into the reservoir is not economically advantageous. The expenses can be reduced if clusters of power plants feed CO2 into shared transport pipelines. The injection into depleted hydrocarbon fields uses established petroleum industry methods and can commence immediately.