Athabasca region deposits

The Athabasca deposits have been known since the early 1800s. The first scientific iaterest ia tar sands was taken by the Canadian government ia 1890, and ia 1897—1898, the sands were first drilled at PeHcan Rapids on the Athabasca River. Up until 1960, many small-scale commercial enterprises were attempted but not sustained. Between 1957 and 1967, three extensive pilot-plant operations were conducted ia the Athabasca region, each leading to a proposal for a commercial venture, eg, Suncor and Syncmde. 

Canada s bitumen resources are situated almost entirely within the western province of Alberta (see Fig. 3.13). These deposits are distributed among three regions Athabasca, Cold Lake and Peace River. Approximately 76% of crude bitumen is produced in the Athabasca region, 22% in the Cold Lake region and 2% in the Peace River region. 

The surface exposures and the near surface deposits (<45 m of cover) of the Athabasca region can be strip-mined for bitumen recovery. They amount to about 10% of the Athabasca deposit. The remainder of the Alberta tar sands lie under 75 m or more of overburden. It is uneconomical to surface mine, and too poorly consolidated for underground mining. These deeper deposits are yielding bitumen to the surface via various in situ techniques. 

Using a "home made" aneroid calorimeter, we have measured rates of production of heat and thence rates of oxidation of Athabasca bitumen under nearly isothermal conditions in the temperature range 155-320°C. Results of these kinetic measurements, supported by chemical analyses, mass balances, and fuel-energy relationships, indicate that there are two principal classes of oxidation reactions in the specified temperature region. At temperatures much lc er than 285°C, the principal reactions of oxygen with Athabasca bitumen lead to deposition of "fuel" or coke. At temperatures much higher than 285°C, the principal oxidation reactions lead to formation of carbon oxides and water. We have fitted an overall mathematical model (related to the factorial design of the experiments) to the kinetic results, and have also developed a "two reaction chemical model". 

The largest tar sand deposits are in Alberta, Canada, and in Venezuela. Smaller tar sand deposits occur in the United States (mainly in Utah), Peru, Trinidad, Madagascar, the former Soviet Union, Balkan states, and the Philippines. Tar sand deposits in northwestern China (Xinjiang Autonomous Region) also are large at some locations, the bitumen appears on the land surface around Karamay, China. The largest deposits are in the Athabasca area in the province of Alberta, Canada, and in the Orinoco region of east central Venezuela. 

The geological stratification of the Athabasca deposit is presented in Figure 2. As with most rivers in this region of Western Canada, the Athabasca River has gouged a deep river valley, exposing the oil sands deposits along its banks. On warm days the bitumen oozes from the river banks and eventually works its way to the water line. Native Indians used this bitumen, mixed with spruce gum, to patch their canoes. 

In the shallow regions of the Athabasca deposit, the oil is in a drainage basin that was filled in with sediments as it was alternately flooded by a sea (estuarial environment) and then rivers (fluvial environment), so that a number of distinct depositional environments of estuarine and marine sediment occurred (10—15). As a result, the oil-bearing sands have great variability in their compositions and properties. 

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