Seven shale plays in Alberta have combined estimated P50 or best estimate resources in place of 423.6 billion barrels of oil, 3,424 trillion cubic feet (Tcf) of natural gas, and 58.6 billion barrels of natural gas liquids, according to a recent report by Canada's Energy Resources Conservation Board (ERCB).
The October 2012 report by ERCB's Energy Resource Appraisal Group assessed the potential resources of the Duvernay, Muskwa, Montney, Nordegg Member and basal Banff and Exshaw formations, also referred to as the Alberta Bakken.
ERCB also conducted a preliminary assessment of the Colorado, Wilrich, Rierdon and Bantry shale units. Estimates for the basal Banff/Exshaw, Wilrich and north Nordegg were included in Alberta's total resources but classified as preliminary.
ERCB, which collected 3,385 samples for evaluation in the summary report, noted that Alberta has no less than 15 formations with potential for shale and/or siltstone-hosted hydrocarbons, ERCB said in the report. Historical estimates for Alberta's original shale-hosted gas-in-place range from 80 Tcf to 10,000 Tcf.
"The results allow us to understand the size and distribution of shale-gas resources in Alberta and may be used to assist in the planning of resource allocation and conservation, commingling and rights assessment, royalty assessment, land and water use, and environmental stewardship," ERCB noted in the report.
ERCB's studies of shale and siltstone-hosted hydrocarbons began in 2006, with an initial focus on shale gas in which oil and gas companies had shown interest.
"As our study progressed, we found that many of the formation we were analyzing also contained a significant amount of natural gas liquids and oil," ERCB noted. "Therefore, we expanded the study to include all shale- and siltstone-hosted hydrocarbons."
The Duvernay shale play in central Alberta has medium estimated shale gas in place of 443 Tcf equivalent, and could anywhere between 353 Tcf equivalent to 540 Tcf equivalent. The Duvernay's oil resources are estimated at 61.7 billion barrels, with a range of 44.1 billion barrels to 82.9 billion barrels. Natural gas liquids in the play are estimated at 11.3 billion barrels, but could be as low as 7.5 billion barrels and as high as 16.3 billion barrels.
The report concluded that the Muskwa formation has initial oil-in-place oil resources of 115.1 billion barrels, with a range of 74.8 billion barrels to 159.9 billion barrels. The play's natural gas resources are estimated at 419 Tcf, with a range of 289 Tcf to 527 Tcf. Natural gas liquids initially in place are estimated at 14.8 billion barrels, with a low estimate of 6 billion barrels to 26.3 billion barrels.
The Montney formation is estimated to have oil resources of 136.3 billion barrels, with a range of 78.6 billion barrels to 220.5 billion barrels. Natural gas resources are estimated at 2,133 Tcf, or anywhere from 1,630 Tcf to 2,828 Tcf. The play is estimated to hold natural gas liquids of 28.9 billion barrels, with a range from 11.7 billion barrels to 54.4 billion barrels.
The Basal Banff/Exshaw shale play has initial oil resources in place of 24.8 billion barrels, with a range of 9 billion to 44.9 billion barrels. The play's natural gas resources are estimated at 35 Tcf, or as low as 16 Tcf and as high as 70 Tcf. Natural gas liquids are estimated at .092 billion barrels, with a range from .034 billion barrels to .217 billion barrels.
The north Nordegg play has shale-hosted oil resources initially in place of 37.8 billion barrels, with a range of 19.9 billion barrels to 66.4 billion barrels. The play's natural gas resources are estimated at 148 Tcf, with a range of 70 Tcf to 281 Tcf. Natural gas liquids are estimated at 1.4 billion barrels, with a range from .5 billion barrels to 3.5 billion barrels.
The Wilrich play has estimated oil resources in place of 47.9 billion barrels, with a range of 20.2 billion barrels to 172.3 billion barrels; mean estimated gas resources of 246 Tcf, with a range of 115 Tcf to 568 Tcf; and natural gas liquids of 2.1 billion barrels, with a range from .7 billion barrels to 4.4 billion barrels.
ERCB noted that the resource endowment estimates in the report should not be confused with recoverable reserves.
"It is not likely that the entire area evaluated in any unit will be economically producible, even assuming that the technology used in hydrocarbon recovery continues to improve in the future."
ERCB said it would revisit the estimates as more production occurs and more data becomes available.
Oil and gas companies that are exploring Alberta's shale potential include Talisman Energy and Chevron
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