Originally published 8/7/08. I was telling a friend about my oil field experiences and linked him to this post and decided it was worth a "bump".
I took these photos a few months ago to post in a political forum I used to frequent; I wanted to (try to) prove to a guy that hydrocarbons were formed by deposits of organic material. He was arguing that, since some Georgia textbook had said "oil came from dinosaurs" that that was what was taught in our schools and it was wrong. (never mind that the textbook was printed in the 50's, and was a grade school primer. That was about his intellectual level, come to think of it)
He was insisting that oil is formed in the earth's core (
abiogenic petroleum origin) and that we were nowhere nearly running out of it and that oil companies kept this "fact" a secret . (and this coming from a guy who said
every Ron Paul supporter was a conspiracy nut)
This is a core sample from one of my dad's wells; it came from approx. 4800 feet and is from the
Brown Dolomite formation.
The large white deposit in the above photo is
chert (sometimes called "flint"); drilling through the dolomite formation is tricky enough*, but these hard layers of chert could tear up a drill bit if not careful.
*Dolomite is very porous, and that's why -- in that particular area -- it is the oil-bearing strata. In other places, where it was necessary to drill deeper to find oil or gas, drilling through this particular formation took special precautions; if the drilling fluid wasn't viscous (thick) enough, or didn't have enough "
filler", the formation could swell from the fresh water and "
stick your bit" and pipe. It is also a "
lost circulation" zone, sometimes sucking in fluid faster than could be pumped down the hole.
This next photo shows just how porous the rock is.
It's so porous, I used to like to pour liquid incense onto the core; it would soak it up and slowly release the fragrance over several weeks time.
This next shot shows some tiny fossils embedded into it. (Some might argue that they're rock, but I took this to my college geology professor and he verified it. He wanted me to give it to him, but he had already stolen a meteorite from me...long story)
No, it wasn't "just" dinosaurs that made oil; my dad used to say it was dinosaur "poop" more than the prehistoric animal remains, but that was...just like that Georgia textbook...a simplification. The organic material that later became oil came from seas that used to cover this area millions of years ago. It wasn't just one time, but several, over millions of years and millions of tons of organics. The tremendous amount of organic material, under tremendous heat and pressure, formed the hydrocarbons.
That's not as nice an example as is this
core sample from Norway, but I think it's still interesting.
My dad and I used to polish rocks, and he made an ashtray out of a slab of core sample. I don't know what happened to it, but it had a beautiful shell in it.
That particular field is nearly played out, but the last time I was out there, they were drilling some injection wells and seemed to be having some success with that method. (
tertiary recovery)
