Lesson 6 - Lesson 6 Your learning objectives for this...

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Lesson 6 Your learning objectives for this lesson; Explain how oil is formed, found, and extracted Discuss environmental implications Articulate oil quality issues Explain Crude Oil, Natural Gas, Tar Sands, and Oil Shale formations Explain Reserve-resource issues Describe crude oil history in PA Crude Oil and Natural Gas Formation As organic material decays, methane is formed and lost into the atmosphere. As the organic material breaks down, depending on the inputs (trees vs. plankton), the different fossil fuels will form. As the material is buried deeper the temperature increases and there is an "oil window", or an opportunity to find oil. If the temperature is too high then all the crude oil will form natural gas instead, and so the oil window closes. Of course, we also find oil at the surface, but this tends to be degraded oil that has lost the more volatile components and so tend to be tar pits (not pools of crude oil). Plankton: 1. On death they (plankton) sink to the bottom of the ocean where the decay process occurs. Think back to all the deep-sea footage you have seen where is it "raining" organic matter. Often the nutrient rich zones are also locations by rivers that carry sediment from the land to the sea. If the dead plankton and sediments fall in quantity it will form an organic rich layer at the bottom of the ocean. There it will be protected from aerobic decay, because of the physical protection (sediment) and the lower oxygen content. 2. Long time periods, millions of years - As the layers are buried deeper and deeper the temperature builds up (as does the pressure) and the layer turns into a rock. However, it is a rock that has significant organic content. Additional time, temperature and pressure and the maturation process produces kerogen. Additional time and the kerogen is transformed into bitumen and then crude oil with associated methane. These materials can escape the source rock and if unchecked can seep into the surface of the ocean (or land) and decay back into carbon dioxide and water. 3. As the oil and natural gas moves through porous rocks if it meets an impermeable layer then it is stuck and the maturation process continues. Thus crude oil and gas "live" within porous rocks not great holes in the ground (unless they are in the strategic petroleum reserve)- more on that later. 4. If we find these structural traps and they contain oil or gas we can extract the fossil fuel and much of it will be combusted to generate thermal energy (for transportation or heat) and yield carbon dioxide and water.
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When we extract crude oil it contains some water. However, even when we extract Pennsylvania crude oil the crude will still contain water but it is NOT fresh water. The water contains salt and many of the other elements in concentrations that we find in the ocean. The disposal of this salt water is an expense. In the good old days it was thrown in a river or stream but the salt would kill the fresh-water fish. Now it is cleaned prior to
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This note was uploaded on 03/30/2008 for the course EGEE 101 taught by Professor Mathews,jonathan during the Spring '06 term at Pennsylvania State University, University Park.

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Lesson 6 - Lesson 6 Your learning objectives for this...

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