Oil sands between 70 to 75 metres of the surface are mined. Hot water is used to separate the bitumen from the sand
PHOTO BY Joey Podlubny
The current method of choice to access
the resource too deep to mine is Steam
Assisted Gravity Drainage (SAGD).
SAGD involves the drilling of two
horizontal wells on top of one another.
Steam is continuously injected into the
top well. It heats the bitumen, which
flows to the bottom well, where it is
pumped to the surface.
Managing sand effectively is the goal at
Lloydminster, and the tool of choice is
the progressing cavity pump. In 2004,
The Peace River oil sands is accessed according to the Alberta Energy and
using a mix of thermal and cold Utilities Board, about 210,000 barrels of
production schemes. Shell Canada uses a heavy oil were produced in Canada using
variation of CSS, with horizontal legs CHOPS. That represents about 22 per
coming off a vertical well in a wagon cent of the country’s daily production,
wheel pattern. Others, like BlackRock and technology continues to evolve to
Ventures, are using horizontal wells to make the process even more efficient
capture mobile bitumen in the deposit. and productive.
production slows and the cycle begins
again.
The main recovery system in the Cold Cold or primary recovery is also used in
Lake oil sands deposit is called Cyclic some areas ot the Cold Lake deposit. A “CHOPS involves the encouragement and
Steam Stimulation, or CSS. In CSS, steam system called Cold Heavy Oil Production sustaining of sand influx because of the
is pumped down vertical wells and the with Sand, or CHOPS, is one of the dramatic improvement in production
oil is allowed to soak for a period of primary recovery technologies being rates that it brings,” says Dr. Maurice
months. Then it is produced until used today. Dusseault, renowned heavy oil specialist
and professor of geological engineering
at the University of Waterloo in Ontario.
The difference between heavy and light oil “If sand is kept out of these wells by
using a filter screen, the production
API Gravity would be two to 20 barrels per day.
However, if sand influx is unimpeded in
any way, the production rates are 20 to
300 barrels per day as a result.”
Degrees on the American Petroleum Institute (API) gravity scale
Specific Gravity
45. 4˚ 800
Light 40.0˚ 825 35.0˚ 850 Light
31. 1˚ 870 900 ( 25. 7˚API)
30. 2˚ 875
Medium 25. 7˚ 920
22. 3˚ 920
21. 5˚ 925
heavy 17. 4˚ 950
13. 6˚ 975
10.0˚ 1000 Heavy
6. 5˚ 1025
Extra heavy (crude bitumen) 3. 3˚ 1050
Density in kilograms per cubic metre
0.1˚ 1075
Industry Government
SOURCE: Petroleum Communication Foundation
At Suffield in the south, conventional
heavy oil pools are rated as world-class
by producers like Harvest Energy Trust.
“These are big pools, and they are very
high quality,” says president Jake Roorda.
“There are several hundred million
barrels in place in these reservoirs.”
Horizontal drilling is the method of
choice at Suffield. What makes the pools
unique is that they are energized by
natural aquifers.
