Technology Steam Assisted Gravity Drainage

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Close to a third of the crude oil Canada produced from oil sands in 2014 used this technology Steam assisted gravity drainage (SAGD) [1].SAGD is an in-situ method that is used to extract oil from oil sand reserves. Developed by Roger Butler [2] SAGD is today one of the primary methods used to extract bitumen. In SAGD shown in the Figure 1.1, pairs of horizontal parallel wells separated by a vertical distance of 4-6m are drilled for one kilometer of a horizontal distance. The upper of the two wells (injection well) is used to inject steam in the formation to lower the viscosity of the bitumen. The lower one (production well) is used to collect the produced oil. The well drilled into the formation removes earth for a well (casing) to be inserted to the well bore. The well bore is then cemented to increase the stability and isolate it from underground water to prevent contamination. A smaller pipe with a number of small slits is then inserted in the reservoir. When steam is injected to the formation a steam chamber around the well is created [3]. The pressure of the steam should be lower than the fracture pressure of the rock mass to prevent the deflection of the rock [4]. Steam injection will go on for months during which the steam chamber expands and the viscosity of the bitumen decreases. This will cause the bitumen to flow down under gravity towards the production well. The produced oil is then pumped to the surface. Surface facilities are then used to separate the water
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