It is estimated that conventional oil production will reach its peak prior to 2025. Unconventional methods of oil production may have the potential to mitigate the effects of peaking worldwide oil production (Mohr et al., 2010). Extra heavy oil and oil that is trapped in tar sands and shale can be retrieved through mining and through in situ techniques. The efficacy of in situ and mining techniques in extracting this unconventional oil was projected under three different models, which were used to estimate when unconventional oil production will peak, and whether alternative methods of production can delay the onset of peak oil. The authors determined that unconventional oil production will peak between 2076 and 2084, and that unconventional methods alone cannot mitigate the onset of peak oil.— Caitrin O’Brien
Mohr, F., Evans, G.M., 2010. Long term predictions of unconventional oil production. Energy Policy 38, 265–276.
S.H. Mohr and G.M. Evans developed a model to project unconventional oil production, including in situ and mining extraction techniques. Unconventional types of oil include extra heavy oil, natural bitumen from oil sands and tar sands, and oil shale. In situ techniques involve injecting steam into the well to heat the oil, forcing the hot oil towards the surface. Steam Assisted Gravity Drainage (SAGD) is a type of in situ technology that extracts the oil through horizontal drilling. Using the Cyclic Steam Stimulation (CSS) method, the well is put through cycles of steam injection, soak, and oil production until the hot oil can be pumped out of the well. The model developed by the authors was calibrated based on Canadian data of historic bitumen production. Mohr and Evans developed the unconventional oil production model based on their previous model for worldwide coal production. Production for mining is determined by the sum of the individual mines in the basin. Production from in situ is identical to the mining model, but the data is from a SAGD/CSS plant rather than a mine. Three scenarios were determined from the model, providing “pessimistic,” “optimistic,” and “best guess” estimates of ultimately recoverable resources from unconventional oil production. Finally, the data extracted from the model were combined with conventional oil analysis and literature to obtain combined oil production projections. The authors compared these results to estimates of worldwide peak oil production, to determine whether unconventional oil production can provide a smooth transition when conventional oil peaks.
Unconventional oil is primarily found in 3 countries: Canada, Venezuela and the United States. The Former Soviet Union is also predicted to contribute considerable amounts of unconventional oil in the future. Mohr and Evans used the in situ model to model in situ natural bitumen and extra heavy oil production, whereas the mining model was used to predict production from mined natural bitumen and shale oil production. Based on the three scenarios, unconventional oil production will peak between 18 billion barrels per year (Gb/year) in 2076 and 32 Gb/year in 2084. The best guess scenario estimates that production will peak at 22 Gb/year in the 2077. Shale oil has the biggest production potential, although it also has the greatest uncertainty regarding its extraction methods and economic viability. Mohr and Evans’s total unconventional oil production projections are higher than the estimates from most scientific literature on the subject, and the authors theorize that this is because their scenarios do not consider economic constraints. In spite of the overall optimistic nature of the assumptions in these scenarios, both the pessimistic and the best guess scenario forecast that total oil production will decline within 5 years. The authors estimate that unconventional oil will only delay the peak of world oil production by twenty-five years at the most. After combining the three scenarios developed in this model with literature projections of oil production, only the optimistic scenario estimates that unconventional oil could partially mitigate the peak of conventional oil production, extending the worldwide oil production peak to 2050. The pessimistic and the best guess scenarios both estimate that total oil production will peak within the next 5 years, and unconventional oil production will not significantly offset this peak.