Peak oil is not a myth
However, this last point is the salient one. Sources of unconventional oil (listed below) such as tight oil (or ‘shale oil’ in popular discourse) are only commercially viable because the need to match the declining rate of conventional oil production has raised oil prices. It is the rate of production of oil that determines its supply, rather than the size of the reserves: ‘The size of the tap, not the tank.’
Energy in, energy out
‘Oil production is predicted to drop by over 50% in two decades’
This means that more energy must be invested to maintain output. As a rough comparison, conventional crude oil production has an EROEI in the range 10–20:1, while tight oil comes in at 4–5:1. Oil recovered from (ultra)deepwater drilling gives 4–7:1, heavy oil 3–5:1, and oil shale (kerogen) somewhere around 1.5–4:1. Tar sands is around 6:1, if it is recovered by surface mining, but this falls to around 3:1 when the bitumen is ‘upgraded’ by conversion to a liquid ‘oil’ substitute.