Carbon intensity of in-situ oil sands operations with direct contact steam generation lower than that of once-through steam generation

The oil sands resource in Western Canada are a considerable energy asset for Canada, but the energy and emissions intensities of producing this petroleum resource are substantially worse than that of conventional petroleum resources. With requirements for carbon-intensity reduction, new, less emissive recovery processes must be developed to enable continued production and cash flow from this important resource. The largest source of carbon emissions on in-situ in oil sands recovery processes, such as Steam-Assisted Gravity Drainage (SAGD), is steam generation, where natural gas is combusted. An alternative to conventional steam generation is Direct Contact Steam Generation (DCSG), where steam is generated in the combustion flame, and with rich oxygen combustion, the steam plus carbon dioxide mixture is injected into the reservoir. We explore the carbon intensity of DCSG and compare it to existing once-through steam generation using life cycle analysis. The results reveal considerable environmental benefits with nearly 30% emission reduction when applying a DCSG in SAGD instead of an OTSG. The results suggest that oil sands operators could improve their emissions intensity significantly if they adopted DCSGs in their operations.