Carbon Capture and Storage (CCS) refers to a suite of technologies that capture carbon dioxide (CO2) emissions and store them in geological formations where they are permanently and safely sequestered. In Canada, Alberta's vast number of depleted oil and gas pools are ideal candidates for CSS storage. In this paper, an applicability study was performed on thousands of candidate gas pools across Alberta, looking at their reservoir quality, storage capacity, cap rock integrity, and well penetration risk. These depleted gas pools were studied against public Government of Canada GHG emissions data via a source-sink workflow that was created to help define regions where it would be logical to identify sequestration hub locations. Candidate gas pools were screened based on original gas in place (OGIP), recovery factor, and proximity to existing infrastructure. Using a probabilistic production forecasting tool, another dimension of analysis was performed to identify future gas pools that will be prime CCS candidates over the next 30 years.
The vast majority of Alberta’s greenhouse gas emissions (GHG) reported in 2020 can be attributed to four facility types. These facilities belong to the following groups (starting with the highest emitter): in-situ oil sands extraction, mined oil sands extraction, fossil-fuel electric power generation, and oil and gas extraction (excluding oil sands). In 2020, these four categories were responsible for 120 Mt of CO2 emissions, which amounts to 81% of all of Alberta’s reported emissions for that year. The oil sands Pathways to Net Zero initiative, an alliance between Canada’s five largest oil sands producers, has announced details of its plan to achieve the goal of net zero GHG emissions from oil sands operations by 2050. Emissions from oil sands extraction were therefore excluded from this study.
Mass CO2 storage (in megatonnes, Mt) was calculated for all 47 thousand gas pools that were available in the 2021 gas reserves dataset made available by the Alberta Energy Regulator (AER). These gas pools were layered as bubbles on a map on top of the point source emission bubbles, and this was followed by a source-sink matching workflow that highlighted two sequestration hub regions of interest: one labelled the Central Hub Region, located from just north of Edmonton down to just south of Calgary; the other named the West Hub Region, which covers the west-central part of the province. See Figure 1.
Results indicate that the Central Hub Region could sequester 4.8 years’ worth of 2020- level emissions in the currently available depleted gas pools. If future depleted gas pools are included, it would have the potential to sequester 5.9 years’ worth. Within the West Hub Region, 12.7 years of emissions could be sequestered by the currently available depleted gas pools. When the gas pools that will be ready for sequestration between 2024 and 2053 are included, the West Hub Region could sequester just over 18 years of CO2. Existing pipeline infrastructure was also considered in this study and, with very few exceptions, the point-source emissions and depleted gas pools were right along major gas pipelines which could be considered targets for reversal from production to injection to support CO2 sequestration.
