Energy Intensity and Greenhouse Gas Emissions from Thermal Enhanced Oil Recovery

Thermal enhanced oil recovery (TEOR) is used worldwide to increase the production of viscous heavy oils. The most common TEOR method injects steam into the subsurface reservoir to reduce the viscosity of the crude oil and allow it to flow. Production of steam for TEOR consumes energy, affecting the energy efficiency and greenhouse gas (GHG) emissions of oil production. This paper calculates the energy efficiency and GHG emissions of TEOR. Results arc generated for generic cases and for California-specific cases. GHG emissions in the generic cases range from approximate to 105 to 120 g of CO2/MJ [gasoline basis, full fuel cycle, lower heating value (LHV) basis] when co-produced electricity displaces natural-gas-fired combined-cycle electricity. The carbon intensity varies with the energy demand of TEOR, the fuel combusted for steam generation, the amount of electric power co-generated, and the electricity mix. The emission range for co-generation-based TEOR systems is larger (approximate to 70-120 g of CO2/MJ) when coal is displaced from the electricity grid (low) or coal is used for steam generation (high). The emission range for the California-specific cases is similar to that for the generic cases.