Intro:
Oil has been a hot topic lately, with many sides arguing for or against increased US domestic drilling as a part of the solution. Instead of proposing a solution this web site tries to provide a better understanding of the underlying factors that shape the debate. We start with a look at the process of oil assessment, which determines where and if drilling will be done, particularly in the 1002 area of Arctic National Wildlife Refuge. This area is a 1.55 million acre strip of land on ANWR’s coastal plain. We then provide some answers to the significant question of why assessments vary. Finally the we look at some consequences of drilling that occurred in other parts of Alaska and point out some less harmful energy sources that might replace or supplement oil. Enjoy.
How is Oil Formed?
Where is Oil Found?
How to Find a Play
How is Oil Formed?
Petroleum, the general name for all carbon byproducts like oil and natural gas, is formed from organic material. This material, coming from land or from dead plankton and other marine organisms, reaches the floors of bodies of water and becomes part of the many layers of sedimentary rock that form there. As these layers form and more layers arrive on top of them the organic material turns into petroleum that is contained in the rock, called source rock. This petroleum becomes oil if the amount of heating and pressure on the source rock is sufficient but not too much. To put it simply oil is considered “mature” petroleum, whereas source rocks that were heated less or more than is required to reach the mature level yield less oil and more natural gas. This occurs in a time frame of 10 to more than 300 million years A rich source rock contains 2% petroleum, while a very rich source rock contains 5% petroleum. (USGS, 1987)
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Where is Oil Found?
(PLAY TIME!)
PLAY: A play is a group of geographical features that have a high probability of containing oil or gas when found together. This is what a play looks like:
What Makes a Play: The first necessary feature is source rock, or rock that would contain petroleum. Since the creation of petroleum increases pressure the petroleum leaves source rock and moves upward. Therefore in order for petroleum to be extracted source rock must somehow be connected to a layer of porous rock which can absorb the oil and other byproducts. Finally, this porous rock needs to be capped off by a layer of harder rock to keep it all in there. (USGS,1987)
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How To Find a Play:
Plays are located (although nothing is certain until they are drilled and extraction starts) and analyzed by geologists using a variety of tools. These include seismic surveys, analysis of geological features on the surface, and gravity and magnetic analysis. Other tools include exploring drills and even smell sensors that are specifically tuned to detect oil. One interesting device is a thumper truck which sends vibrations through the ground that are measured on the way back up. |
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Off-Shore Seismic Survey |
Thumper Truck |
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Next: How Oil Reports Work
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References
