GEOL 115: The Earth’s Energy Resources

We started this class by looking at some plate tectonic reconstructions. THere are a number of these on the web that you can look at and one of the better ones is here.

We then talked about clastic reservoirs. Let us first define the term clastic.

clastic- a term used to describe rocks composed of fragments of older rocks.

You can get good sand reservoirs in any environment where sand is deposited. Examples include fluvial systems (rivers), beaches, and eolian systems (wind deposited sand). The primary targets for petroleum exploration, however, are those sands that were deposited in deep water. Turbidite sand reservoirs are clastic petroleum reservoirs that host significant reserves in the Gulf of Mexico, offshore California, offshore West Africa and elsewhere. We looked at video of a “turbidity current” (strictly speaking a subaqueous debris flow) in class. It has been well known that these sands make good reservoirs where the sands are thick. Some recent discoveries (in the last 15 years) have demonstrated that excellent production can be gained where the sands are thin but where many sand layers are stacked up. The Thunder Horse discovery in the Gulf of Mexico is a good example.