Re: The graphs in figure 7 don't match.

I don't see it, can you precise?

Re: If you want to show remove the effects of Saudi Arabia' spare capacity (existent or not) from the graph you should keep its production constant (at 8.6 or 9.6 mbpd) during the entire period.

It's a good idea, another suggestion is to estimate non-opec decline rates.

I don't see it, can you be precise?

The scales on y-axis on the two graphs in figure 7 don't match, and the final value is -4 on the upper and -6 on the lower. It appears that you used the same data as in fig 13 for the upper graph of fig 7.

The scales don't match because one is the annual production loss (i.e. P(t+1)-P(t)) in mbpd and the other one is the decline rate per year in % (i.e. P(t+1)/P(t)*100-100). They look almost the same but they are not.