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u Oil
resource base
uFigure
captions
uBitumen
uOther
resources
uP
& S recovery
uFuture
recovery
uTertiary
recovery
uWeyburn
project
uReferences
u Oil
resource base
uFigure
captions
uBitumen
uOther
resources
uP
& S recovery
uFuture
recovery
uTertiary
recovery
uWeyburn
project
uReferences
u Oil
resource base
uFigure
captions
uBitumen
uOther
resources
uP
& S recovery
uFuture
recovery
uTertiary
recovery
uWeyburn
project
uReferences
u Oil
resource base
uFigure
captions
uBitumen
uOther
resources
uP
& S recovery
uFuture
recovery
uTertiary
recovery
uWeyburn
project
uReferences
u Oil
resource base
uFigure
captions
uBitumen
uOther
resources
uP
& S recovery
uFuture
recovery
uTertiary
recovery
uWeyburn
project
uReferences
u Oil
resource base
uFigure
captions
uBitumen
uOther
resources
uP
& S recovery
uFuture
recovery
uTertiary
recovery
uWeyburn
project
uReferences
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Oil Resource Base (Bitumen)
Alberta
original in place bitumen accumulations are confidently estimated to be
~269 x 109 m3 (1.7 x 1012 bbls; Marsh,
2006; AEUB, 2006; Procter et al., 1984, p. 48). Alberta original
in-place bitumen reserves are estimated ~28.4 x 109 m3,
(179 x 109 bbls; Marsh, 2006; AEUB, 2006), although this may
increase. The official estimate of bitumen reserves includes
industrially recognized reserves that comprise at least 2.6 x 109
m3 (16 x 109 bbls; CAPP, 2005) initial in-place
in-situ bitumen, with no primary recovery , and surface mineable
bitumen accumulations of ~1.44 x 109m3 (9 x 109
bbls; CAPP, 2005).
Oil Resource Base (Other Resources)
Tertiary recovery of conventional oils is a minor effort, in part
because of history, availability, and the cost of miscible fluids, but
new efforts (Figures 2 and
3) are providing a previously ignored
potential conventional oil resource, which competes for attention with
the non-conventional resources.
Tertiary recovery efforts also compete with other potential
non-conventional resources. Currently there are neither significant
shale- oil nor oil -shale developments, although potential exists for
both. Major bituminous shales occur across the WCSB, with the most
significant occurring in Devonian Duverney, Devonian and Carboniferous
Bakken/Exshaw, Jurassic Fernie, Upper Cretaceous Boyne and Favel (white
speckled shales equivalent to Greenhorn and Niobrara) formations (Creaney
et al., 1994). These formations produce small conventional volumes, but
the shale- oil resource is neither well described nor exploited. Some
bituminous formations are mineable oil shales, the upper Cretaceous
being most important. There is no oil -shale resource estimate; yet
outcrops are commonly 20-40 m thick, extending over hundreds of
kilometres. Yields up to 100 litres oil /tonne were obtained from the
Pasquia Hills, Manitoba (Macauley, 1984). Immense coal resources (Smith,
1989) host natural gas from coal that has begun to augment the gas
supply. A reliable natural gas supply is important for several recovery
technologies, particularly for bitumen, but in the future these coals
may also be a source for synthetic oil .
Current Primary and Secondary Recovery :
Most
production employs primary natural depletion, or secondary recovery ,
most commonly pressure maintenance. Primary recovery factors vary. The
average WCSB primary RF is ~14%. The average is lower for heavy oils,
where primary recovery can be 5% or lower. Typically, primary recoveries
are ~16% for Paleozoic carbonates and even higher, exceeding 19%, for
non-biodegraded Mesozoic reservoirs. Secondary recovery commonly adds an
incremental 4%-10% recovery . Secondary recovery can be spectacularly
effective, as in the Northwest Territories, where production comes
primarily from Devonian carbonates and most of that from the Norman
Wells reef. There secondary recovery increased the recovery from the 16%
typical of Paleozoic carbonates to 46%, adding an incremental 15.2 x 106m3
(96 x 106 bbls). Elsewhere secondary recovery results are
more modest. Most of the incremental 957.8 x 106m3
(6,034 x 106 bbls) from secondary recovery is from Alberta,
where secondary recovery identified an incremental 652.0 x 106m3
(4,108 x 106 bbls). In Saskatchewan 4% or 233.9 x 106m3
(1,473 x 106 bbls) has been added mostly from Carboniferous
subcrop pools. The use of secondary schemes in Manitoba has been
negligible and only 1% or 1.3 x 106m3 (8 x 106
bbls) is attributable to secondary recovery .
Future Recovery :
The
WCSB is a potential target for established and new recovery and
stimulation technologies, including, miscible floods, simulated
horizontal wells, and SAGD/JIVE. A recent oil supply model (NEB, 2006)
suggests WCSB oil supply will increase from 2005 volumes of 365 x 103m3/day
(2.3 x 106 bbls/day) to 613 x 103m3/day
(3.9 x 106 bbls/day) by 2015, due to increased bitumen
production alone. The model suggests that conventional oil production
will decline in spite of improved recovery (NEB, 1999; 2003). Still, the
model suggests that future improvements in conventional light and heavy
recovery will contribute 722 x 106m3 to 794 x 106m3
(4.55 x 109 bbls to 5.00 x 109 bbls; NEB 1999;
2003; CAPP, 2005). This represents an incremental 16%-19% increase in
recovery and a volume comparable to the remaining established reserve.
It implies that average recovery factor increases from 21%,
currently, to 27.5%. The NEB (2001) increased conventional heavy oil 30%
over previous resource estimates (Lee, 1998), and both heavy- oil and
oil -sand resource bases may increase as technology develops. Shale oil
and oil shale are not yet part of supply, and their input could add
significantly to recovery growth. While encouraging, it will require
much study and many more projects to know if the inferred recovery
improvements can be commercial.
Current Tertiary Recovery :
Aside
from a few projects, often technology demonstrations, tertiary recovery
has not been applied widely (Figure 4).
Overall, to the end of 2004, tertiary recovery produced only an
incremental 209.0 x 106m3 (1,317 x 106
bbls) accounting for less than one percent increase in recovery . Some
regions, notably Manitoba, British Columbia, and the Northwest
Territories have effectively no contribution from tertiary programs.
This is not indicative of the tertiary programs, but rather it indicates
the lack of their application. Tertiary programs have been historically
restricted to Alberta, where projects added an incremental 176.9 x 106m3
(1,071 x 106 bbls), resulting in a 2% increase in reserves.
Alberta tertiary recovery projects do not include in-situ oil sands
projects, such as cyclic steam stimulation project at Cold Lake, or
Steam Assisted Gravity Drainage (SAGD) projects, which produced 203.5 x
106m3 (1,282 x 106 bbls) bitumen by the
end of 2004 (CAPP, 2005), all of which is attributed to tertiary
recovery . The recoverable reserve of in-situ oil sands 534.8 x 106m3
(3,369 x 106 bbls), is a small fraction of the initial
in-place bitumen (ibid.).
Weyburn and Midale Projects
In
Saskatchewan, the small incremental volume, 32.0 x 106m3
(202 x 106 bbls) from tertiary programs conceals the
importance of the Weyburn CO2 sequestration and tertiary
recovery project (Figures 2,
3, 5). The
project, in a Carboniferous carbonate pool, will produce an incremental
20.6 x 106m3 (130 x 106 bbls), using
miscible or near-miscible CO2 displacement from a pool that
produced 53.2 x 106m3 oil (335 x 106
bbls) since 1955. Important recovery improvements accompanied the
in-fill drilling program that preceded the CO2 flood. The
project extends field life by ~25 years, and recovery factor improves
~28%, from the CO2 flood alone. It will permanently sequester
~20 million tonnes CO2. Plans are underway to apply a similar
scheme of enhanced recovery to the nearby and geologically similar
Midale Field.
References
AEUB, 2006, Alberta's reserves 2005 and supply/demand
outlook 2005/2015: Alberta Energy and Utilities Board, Calgary, CD-ROM.
CAPP (Rodriguez, S. content coordinator), 2005,
Statistical Handbook 2005: Canadian Association of Petroleum Producers,
Calgary, CD-ROM.
Creaney, S., Allan, J., Cole, K.S., Fowler, M.G., Brooks,
P.W., Osadetz, K.G., Macqueen R.W., Snowdon, L.R., Riediger, C.L., 1994,
Petroleum generation and migration in the western Canada Sedimentary
Basin (Chapter 32), in G. Mossop and I. Shetsen (compilers),
Geological Atlas of the Western Canada Sedimentary Basin: Canadian
Society of Petroleum Geologists and Alberta Research Council, Calgary
and Edmonton, p 455-470.
Lee, P.J., 1998, Oil resources of Western Canada:
Geological Survey of Canada, Open File Report, 3674, 142 p.
Macauley, G., 1984, Geology of the oil shale deposits of
Canada: Geological Survey of Canada Paper 81-25, 65 p.
NEB, 1999, Canadian energy supply and demand 1999 to
2025: National Energy Board of Canada, Calgary, 96 p.
NEB, 2001, Conventional heavy oil resources of the
Western Canada Sedimentary Basin: Technical Report, National Energy
Board of Canada, Calgary, 96 p.
NEB, 2003, Canadian energy supply and demand 2003 to 2025
(update of the 1999 report of the same name dealing primarily with
errata): National Energy Board of Canada, Calgary, 96 p.
NEB, 2006, Canada's oil sands: Opportunities and
challenges to 2015: An update. Energy Market Assessment June 2006,
National Energy Board of Canada, Calgary, 71 p.
Procter, R.M., Taylor, G.C., and Wade, J.A., 1984, Oil
and natural gas resources of Canada 1983: Geological Survey of Canada,
Paper 83-31, 59 p.
Smith,
G.G., 1984, Coal resources of Canada: Geological Survey of Canada Paper
89-4, 146 p.
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