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Oil sands must be mined or recovered in-situ. Deposits close to the surface are mined while resources more than 75 metres below the surface require in-situ recovery.
SAGD
Total E&P Canada will recover bitumen from the deeper deposits using a recovery technique known as steam assisted gravity drainage (SAGD). Pairs of parallel horizontal wells will be drilled to recover bitumen continuously from the McMurray formation. Steam is injected into the upper well bore and oil is produced from the lower well bore.
The SAGD process runs two directional wells approximately 5 metres apart. Steam is injected through the upper wellbore (1), the steam then permeates the oil sand, heating the oil and thus reducing the oil viscosity (2). The heated oil and condensed steam then flow to the surface through the lower wellbore (3).
Over time, the steam chamber grows in size resulting in higher production rates. During the rise period the oil production rate increases steadily until the chamber reaches the top of the reservoir.
This vertical cross-section shows the steam chamber at a later stage, where reduced viscosity and a horizontal production well allow practical rates without steam production.
Injected steam replaces produced oil allowing continuous heating of the reservoir and drainage of the heated oil together with condensed steam.
For a more detailed explanation of the SAGD process, and its advantages over other methods, read this excerpt from Dr. Roger Butler's Report.
Mining
Ore is expected to be mined using traditional truck and shovel mining techniques. Mining shovels dig into the sand and load it into large trucks. The mined ore passes through crushers where it is prepared for extraction. Hot water is added to create an oil sand slurry. This is fed via hydro transport to the extraction plant where bitumen is extracted in separation vessels. Separating bitumen from sand and water results in tailings which are pumped to ponds where water is recovered and recycled through the process.
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