Test Your Geological Skills

This is the second in a series of multiple choice and true or false questions designed to test your basic oil and gas know-how regarding geology and stuff that went on years ago below ground level, down there in the dark. Believe it or not, there are still wells drilled in America, indeed all over the world, that don't have anything to do with shale and require fundamental understanding of structural traps and hydrocarbon migration. Stuff like this may come up at this years Christmas party and its good to be prepared...

True or false: the above photograph is an image of a big pile of grandma's gelatin dessert somebody accidentally sat on over the Thanksgiving holidays?

The answer is: false.

This is actually an image of a fruit salad that was intentionally made to resemble a geological phenomenon known as a "graben," complete with corresponding normal faults, right and left. This jello sculpture was entered into the GeoBakeoff at the 2017 Annual Meeting Of the London Geological Society. It received an award, I believe, and was then eaten.

Grabens in real life look like this one, in Iran:

Grabens occur mostly in conjunction with normal faulting in the subsurface that cause "blocks" of sediments to drop (graben), or get pushed up (horst), so to speak. If you are in the shale business this sort of stuff is NA, or not applicable, so you can think of graben and horst blocks sort of like buried trenches and ridges. Fortunately the Wolfcamp is not all broken up like this or the Permian Basin subsurface would have horizontal laterals in it that look like a giant bowl of noodles.

One of the most well known graben systems in the world is the Viking Graben in the Norwegian Sector of the North Sea that has very fractured, vugular, Cretaceous-aged "chalk zones" in it that are plum full of oil and gas. Most of the great, Brae "play" is in the Viking Graben.


My apologies to my geologist friends for my descriptive mistakes, errors and omissions. I am a card carrying member of the AAPG, and my work requires that I often have to pretend to be a geologist, but that does not mean I actually are one.