Some, maybe even this guy, appear to just extrapolate current trends in production and rates to come up with conclusions like this.
I have serious doubts that the underlying technical abilities exist to do this extrapolation like the IEA is doing.
One needs to pay attention to the rock itself and where it exists. Companies typically drill the best wells to begin with, then the well capabilities taper off as the rock is not as good to frac, the maturity level is not ideal, the liquids are not the most conducive to easy flow, etc.
Example of paying attention to the underlying technical premises is the extensive writeup then subsequent writedown in the Monterrey shale within just a few years. There never was foundation to support that large amount of technical resources to exist to begin with.
I have thought for some time that sometime in the next decade we will exhaust the exploitable unconventional liquid horizons to an extent that the inevitable decline in keeping liquid production rates at high levels will occur.
Natural gas, not oil, is the big opportunity for decades to come.
And I remain unsure of what he means by a 'second wave of shale'. It may be the abilities to move more fluids via pipelines for export but am unsure.