Heavy Oil and Tar Sands

1
Heavy Oil and Tar Sands

• by
• Greg Croft
• Presented to the Nuclear Engineering Seminar
• University of California, Berkeley
• February 5, 2007

2
Heavy Oil and Tar Sands

• Heavy oil and tar sands are formed by the
  biodegradation of light oil.
• Most heavy oil production technology was
  developed in California.
• The heavy oil resources of Venezuela and Canada
  are the Worlds largest hydrocarbon
  accumulations.
• Heavy oil and tar sands also occur in Russia,
  Nigeria, the Malagasy Republic and Utah.
• These other accumulations are one to two orders
  of magnitude smaller.

3
Oil Shale Versus Tar Sands
HYDROCARBON
Conventional
RESERVOIR
Unconventional
Most Oil Production
Athabasca Orinoco
Conventional
Increasing Cost per Barrel
Bakken Austin Chalk Monterey
Un- conventional
Oil Shale
4
Steam Injection

• Steam injection was pioneered by Shell at Mene
  Grande in 1956, but was only partially
  successful.
• Steam injection can be cyclic or continuous.
• Continuous steam injection was developed by Getty
  Oil in California in the sixties.
• Cyclic steam injection (huff and puff) has been
  used at Cold Lake since the seventies.
• Steam-assisted gravity drainage (SAGD) is a new
  process developed in Canada.

5
Steam Injection in California

• Incremental recovery was 100 million barrels in
  2005.
• 486 million barrels of steam were injected in
  2005.
• Steamflood used 374 million barrels of steam in
  2005.
• The largest projects are in Kern County.
• Midway Sunset is the largest oil producer in the
  lower 48.
• Other Kern County fields are Kern River, South
  Belridge and Cymric.
• Coalinga (Fresno County) and San Ardo (Monterey
  County) are also large.

6
Worlds Largest Oil Accumulations
Source Roadifer 1987
7
Western Hemisphere Alberta Oil Sands

• The Canadian Association of Petroleum Producers
  estimates that production from oil sands in
  Alberta will be 2.8 million BOPD in 2015, up from
  1.2 million BOPD in 2004.
• In the Athabaska area, mining operations are used
  to recover solid hydrocarbons from near-surface
  sands.
• At Cold Lake, Wabasca and Peace River, cyclic
  steam injection and SAGD are used to recover very
  heavy crudes.

Alberta
Athabasca
Peace River
Wabasca
Cold Lake
Edmonton
Lloydminster
Red Deer
Calgary
8
Alberta Tar Sands Production Methods

• At depths of up to 100 meters, tar sand is mined.
• At depths of 100 meters to 450 meters, steam is
  injected to enhance oil recovery.
• At depths of more than 450 meters, heavy oil is
  produced cold, which greatly reduces the recovery
  factor.
• Horizontal wells are used for in-situ production
  because high drawdown pressures result in sand
  production.

9
The Big Number

• Canada estimates 172 billion barrels are
  recoverable from the oil sands.
• Estimate is 25 billion barrels mineable.
• Other 147 billion barrels is in-situ.
• In-situ reserves are based on 20 recovery for
  steam and 5 for cold production.

10

•                                                   
                              
• Established technology
• SAGD technology will develop majority of
  non-mineable oil sands
• Good reservoir - lower steam/oil ratios
• High recovery factor anticipated - 60 percent
  plus

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Environmental Considerations

• Reclamation is required.
• Natural vegetation is mostly poplar forest.
• Mining is 100 surface disturbance.
• In-situ methods can be as low as 5 surface
  disturbance.
• Water availability can be an issue in winter.

12
Alberta - The Physics Problem

• Reservoir is 100 to 200 feet thick.
• Permeability is 2 to 10 darcies.
• Reservoir must be heated such that steam phase is
  continuous from producer to injector.
• Project life could be 50 years.
• Athabasca deposit is 200 miles long and 100 miles
  wide.
• Well pad spacing depends on length of laterals.
• Steam must be injected over vast areas.

13
Venezuelas Orinoco Heavy Oil Belt
Caribbean Sea
Trinidad
Machete
Zuata
Cerro Negro
Hamaca
Venezuela
N
14
Orinoco Heavy Oil Belt, Venezuela
Carabobo 227 BBO
Boyaca 489 BBO
Ayacucho 87 BBO
Junin 557 BBO
Ciudad Bolivar
lt 100 feet net oil sand
100 200 feet net oil sand
Orinoco River
200 300 feet net oil sand
gt 300 feet net oil sand
Source PDVSA
15
Orinoco Heavy Oil Belt

• Original oil in place is estimated to be 1,360
  billion barrels.
• Producing depths range from less than 1,000 to
  more than 4,000 feet.
• Oil is present in multiple sands with shale
  breaks.
• The oil is much less viscous than in the Alberta
  oil sands.
• Current cold production is 600,000 BOPD.
• Cyclic steam stimulation produces good flow
  rates.
• Steam is only used in a pilot project.

16
Natural Gas Supply

• Both in the US and worldwide, gas is becoming a
  larger component of fuel production.
• The gas supply in the US has repeatedly surpassed
  expectations.
• Unconventional reservoirs have brought US
  lower-48 gas production almost back to its 1972
  peak.

Oil Gas
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Conclusions Heavy Oil and Tar Sands

• Canadas big number is too small.
• Venezuela also represents a very large resource.
• Steam flooding technology was developed in
  California.
• Steam generation is typically 70 of operating
  costs.
• Breakeven costs in Alberta are about US35 per
  barrel.
• Breakeven costs in Venezuela are about US22 per
  barrel.
• Oil shale development is uneconomical with
  current market conditions and technology.

18
Conclusions Gas Versus Nuclear

• The interest in nuclear power for the Alberta oil
  sands is based on concerns about the gas supply.
• The long-term gas supply in North America is
  difficult to predict.
• Nuclear power reduces risk by eliminating
  sensitivity to the gas price.
• Nuclear steam generation will have to compete
  with gas and petroleum coke.