Matt, it's not the normal Hubbert curve but a "linearization" of a Hubbert curve. It's a mathematical technique to estimate the total oil reserve from the oil production so far.

Maybe an HL expert can explain further.

Thanks, Bob. I get a little overwhelmed by all these charts; and for that matter, the nitty gritty. No doubt I should be seeking more mainstream answers to my simple "What The?" questions (though many of you do dumb it down for me; thanks!), but of course easy answers are hard to find.

Regards, Matt B