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Unformatted text preview: Chapter 1: Petroleum Geology Review Petroleum reservoirrock formation that holds oil and gas Photosynthesizing microorganisms in the oceans represent earth's largest biomass, which is preserved and converted into gas land plants with woody materials become coal Organic theorydead organisms sank to bottom of water, trapped in oxygen-less mud Inorganic theoryoil either left over from formation of solar system or later from deep within earth 150 deg F: oil 225-350 deg F: methane gas 500 deg F: organic matter destroyed as petroleum source Hydrocarbons: Origin of Petroleum Reservoir rock must be at least 10% porous to be commercially valuable Permeabilityhow well pores are connected (in millidarcys) Easy to extract: sandstones and carbonates, most porous and permeable Difficult: shale (porous but ~0% permeability) and tar sands (sticky oil) Porosity and Permeability Organic theoryit didn't form in large amounts, but rather deep pressure forced it upward & it joined with...
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- Spring '11