Print this page
Click to view
presentation in PDF format.Geological Aspects of Carbon Dioxide Sequestration in Northeast British Columbia, Canada*
By
Alf Hartling1
Search and Discovery Article #80010 (2008)
Posted August 1, 2008
*Adapted
from oral presentation at AAPG Annual Convention,
1Resource
Development and Geoscience Branch, British Columbia Ministry of Energy, Mines
and Petroleum Resources, Victoria, BC, Canada.
([email protected]a)
Geosequestration of carbon dioxide (CO2) is feasible for reducing
greenhouse gas emissions in Northeast British Columbia, Canada. Currently
there are 12 acid gas disposal sites permanently storing ~130,000 tonnes of
CO2 per year in saline aquifers or depleted natural gas
reservoirs. Gas pools are the most secure storage options, having
demonstrated the ability to trap natural gas over geological time. Nearly
67% of existing pools appropriate for geosequestration will not be depleted
until post-2020.
The near-term need for large-scale storage sites will necessitate using saline
aquifers to bridge the timing gap. Triassic and Devonian aquifers are likely
candidates offering a good combination of storage security, capacity, and areal
distribution. Both systems are isolated by thick aquitards that restrict
interformational hydrodynamic flow. Lateral facies changes and updip erosional
events create stratigraphic barriers, further impeding fluid movement.
The Triassic Doig-Halfway-Charlie Lake succession represents a thick
transgressive-regressive cycle of shoreline to shelf sandstones and shales
culminating with a mixed clastic-carbonate deposit. The overlying marine
carbonates of the Triassic Baldonnel and Pardonet formations represent the final
flooding stage. Erosion to the northeast limits Triassic storage opportunities
to the southern area.
To the north, the Middle Devonian Keg River-Sulphur Point-Slave Point succession
of reefal to platform carbonates were deposited as a series of shallowing-upward
cycles and offer ample CO2 storage capacity. Dolomitization
associated with regional faulting and hydrothermal fluid migration has created
excellent reservoir characteristics primarily at shelf margins. The regional
geological/tectonic setting and reservoir characteristics of these Triassic and
Middle Devonian strata make them excellent candidates for CO2
storage.
|
|
Approximately 1.5 Gt of CO2 storage capacity will
become available as major gas pools are depleted in Northeast
British Columbia. Poor timing of availability and geographic
distribution of depleting pools require use of saline
formations. Triassic reservoirs are the best storage candidates
in the southern portion, while Devonian rocks are likely the
only option in the north. Acid gas (H2S and CO2)
re-injection projects demonstrate the technological feasibility
of geosequestration of CO2.
Bachu, Stefan, 2008, CO2
Sequestration Program web
site map:
http://www.ags.gov.ab.ca/co2_h2s/program_components.html.
Edwards, D.E., J.E. Barclay, D.W. Gibson, G.E. Kvill, and E. Halton, E. 1994. Triassic
strata of the Western Canada Sedimentary Basin,
in Geological Atlas of
the Western Canada Sedimentary Basin, G.D. Mossop and I. Shetson
(compilers): Canadian Society of Petroleum Geologists, p.
257-275.
ERCB/AGS web site poster, 2006, Acid Gas and CO2 Storage: http://www.ags.gov.ab.ca/co2_h2s/co2_acidgas.html.
Petrel Robertson, 2003, Exploration Assessment of Deep Devonian Gas Plays, Northeast British Columbia.
|
