Geological Sequestration of Carbon Dioxide A Viable Solution for Western Canada and Alberta s Climate Change Taking Action Stefan Bachu Alberta Geological Survey
Anthropogenic Carbon Balance Net C = P x GDP P E GDP C E ( GDP) x ( ) x ( ) -S
Means of Geological Sequestration or Storage of CO 2 Trapped in the pore space (stratigraphic, structural traps) In solution (dissolved in reservoir oil or formation brine) Adsorbed onto coal matrix (uneconomic coal beds) In salt caverns Hydrodynamically trapped in deep, long-range flow systems Minerally trapped through carbonate precipitation
Geological Sequestration Options Enhanced oil and gas (O&G) recovery Depleted O&G reservoirs Enhanced coalbed methane (CBM) recovery Depleted CBM reservoirs Deep saline aquifers Salt caverns
Worldwide Experience with Geological Sequestration of CO 2 76 Enhanced oil recovery operations (~70 in the U.S., 2 in Canada), since 1972 58 Acid gas disposal operations (42 in Canada, 16 in the U.S.), since 1989 1 CO 2 disposal operation into an aquifer (Sleipner in the North Sea), since 1996 1 enhanced coalbed methane recovery (San Juan basin, U.S.A.)
Process Scales for CO 2 Geological Storage and Sequestration
Seismicity in Canada
Suitability of the Western Canada Sedimentary Basin for CO 2 Geological Sequestration
Alberta s Climate Change Taking Action Kyoto Protocol Taking action Continental reality: the U.S. & energy security and innovation - secure energy, clean energy, coal and hydrogen based Alberta s policy clearly parallels U.S. policy Target to reduce CO 2 emissions intensity by 2020 at 50% of 1990 levels Technology driven Among areas of action: Carbon Management, focused on Carbon Dioxide Capture and Sequestration
CO 2 Emission Reductions Short timeframe (2010): 22% reduction in emissions (20 Mt CO 2 ) Long timeframe (2020): 50% reduction in emissions (60 Mt CO 2 )
Energy Research and Technology Areas Oil sands (lower intensity) Enhanced recovery: oil, CBM Clean coal Alternative energy Carbon management
CO 2 Sequestration in Oil and Gas Reservoirs In stratigraphic and structural traps that held hydrocarbons for millions of years Dissolved in reservoir oil
Capacity for CO 2 Sequestration in Oil and Gas Reservoirs in Alberta Ultimate theoretical CO 2 sequestration capacity 30,646 gas pools 13,560 Mt CO 2 9,128 oil pools 1,090 Mt CO 2 4,371 oil pools suitable for EOR 690 Mt CO 2 Total 14,740 Mt CO 2
Predicted CO 2 Sequestration Capacity in EOR in Alberta s Oil Pools @ 100% HCPV
CO 2 Sequestration in Deep Saline Aquifers Dissolved to saturation in formation water (brine) In free phase in long-range flow systems
CO 2 Phase at the Top of the Viking Aquifer, Alberta Basin
Capacity for CO 2 Sequestration in Solution in the Viking Aquifer, Alberta Basin Total capacity: 200 Gt Capacity in the suitable region: 106 Gt
CO 2 Sequestration in Deep Unmineable Coal Beds Adsorbed onto the coal surface
Stratigraphic Distribution of Coal Beds in the Alberta Basin
Net Coal Thickness in the Ardley Coal Zone in Alberta Contours in metres
CO 2 Sequestration in Deep Salt Caverns As a dense fluid in solution salt caverns Salt will close in until the pressure inside equalizes the weight of the overburden
Distribution of Salt Beds in the Western Canada Sedimentary Basin
Predicted Pressure Build-up in a Salt Cavern in the Lower Lotsberg Salt, Alberta Basin, Filled with Dense Carbon Dioxide
Safety of CO 2 Geological Sequestration The safety record of enhanced oil recovery and acid gas injection operations in North America shows that short-to-medium-term (up to decades), reservoir-scale geological sequestration of CO 2 is a safe operation Main question: Safety of large (basin) scale operations over the long term (centuries)
Acid Gas Injection Operations in the Alberta Basin
Conclusions Alberta and the western provinces can achieve very ambitious targets for the reduction of CO 2 emissions into the atmosphere by sequestering CO 2 in the subsurface Although technologically feasible, the geoscience, safety and economic aspects need addressing before large scale implementation