Greener EOR: Employing Cogeneration to Improve the Energy Efficiency of Thermal EOR projects

Abstract

Thermal EOR technologies such as Cyclic Steam Stimulation, Steam Assisted Gravity Drainage and Steam Flood can be extremely energy intensive, requiring the combustion of fossil fuels to produce the steam required, with the resulting emissions of carbon dioxide and other pollutants. Newer technologies such as Solvent Extraction may also require the injected medium to be heated to maximise oil recovery from the reservoir. EOR projects tend to generate the heat and power required in separate facilities, with the electricity often being supplied from a remote central generation facility. In many cases it may be possible to integrate a cogeneration plant into the EOR process. Using a single facility, a locally available fuel can provide both the power and heat required for the project, therefore optimising global energy efficiency and achieving very high overall fuel efficiencies, usually in excess of 75%, while helping to reduce the global CO2 footprint of the Oil & Gas industry. In most cases the heat produced by a Cogeneration plant is a byproduct of electricity production, but it is also possible to utilise waste heat or waste gases from some processes to produce useful energy. There are numerous different ways to configure a Cogeneration plant depending on the type of fuel available and the ratio between power and heat required by the project. This paper will examine some of the different Cogeneration configurations and fuel options using Gas or Steam Turbines, or a combination of both, that could be applied to a thermal EOR project. Gas Turbine combustion can also play a significant role in the overall environmental as well as economic benefits of cogeneration in an EOR facility. The use of a wide range of fuels requiring little or no pre-treatment in a Dry Low Emissions combustion system reduces on-site energy consumption and helps reduce emissions to atmosphere of pollutants such as NOx.