[caveat emptor]

You got it right except for the 'tax protection' angle.

Hmm. "Market risk reduction" via "production tax credits" sounds a lot like like "some sort of tax protection against oil price volatility".

"There is a market risk in shale, as I pointed out, because of the oil price volatility over the last 87 years and the episodic way shale has been handled by the world market and government. Market risk reduction is among the DOE recommendations, and that translates into production tax credits..."

[SAJ]

The point is that ‘production tax credits’, beyond some sort of depletion allowance, are simply not necessary. Shell et al. will angle for tax credits of one or another kind, but that, of itself, is not any sort of reason to grant them.