Environmental Stewardship In The Alberta Oil Sands

In sub Kim

Dr. Leo Oriet

Engineering and the Profession

16 April 2015

Environmental Stewardship The Alberta Oil Sands is the biggest energy project on the planet. The oil sands underlie more than 140,000km2 in north and eastern Alberta, Canada. There are 175 billion barrels of recoverable bitumen in Alberta, and this unconventional oil is extracted by two different methods. Oil sands, referred as tar sands, are a natural mixture of sand, clay, water and a type of heavy oil “bitumen”. Crude bitumen comprises approximately 10% of the oil sands. When it is located less than 75 metres below the surface, pit mining techniques (surface mining method) is used. 60% of oil sands production is from surface mining method. For surface mining method, trees,

For oil sands mining process, it is required to use fresh surface water or recycled water. About 12 barrels of water are needed to produce one barrel of bitumen in surface mining method. The majority of fresh water comes from the Athabasca River. 82% of water used for the oil sands projects comes from the mainstream of the Athabasca River. According the National Energy Board, the new fresh water used to produce one barrel of synthetic crude oil by surface mining method requires only 2.5 to 4.0 barrels of water. And after recycling of process water, the final ratio of water consumption in situ methods is about 1barrel of water for 1barrel of bitumen. However, bitumen productions are expected increased more than triple by 2030, the demand for water also would increase. For in situ drilling method, water mainly used to generate steam. And wastewater is usually disposed of in deep disposal wells. In 2009, 242 million barrels of bitumen produced by situ drilling method. When consider the scale of the oil sands production by situ operations, the annual water consumption is significant. Because more than 80% of bitumen reserves can be extracted by situ drilling method, the required water would be as great. It impacts on water flow, the annual average water flow of the Athabasca River due to decline in the water supply. For over 30 years, runoff has decreased by 50% of the Athabasca Basin. A decline in the water supply is caused by increase in temperature. Some experts projected that combination of increase in temperature and water withdrawals, water flows in winter would less than 100 ft3 per seconds in the future. Also, they predicted that water flows in the oil sands region would decrease by 8% to 26% when an average temperature increase 3 C° by