Petroleum systems
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A petroleum system includes all geological processes and elements needed to generate, accumulate, and store petroleum, natural gas, and other hydrocarbons. These elements include a source rock (which contains organic matter that can generate oil or natural gas), a pathway for hydrocarbons to move from their source to a reservoir (a subsurface layer of rock that can store and transfer liquids and/or gases), a trap (a rock formation that seals liquids and/or gases inside it), and a seal (an impermeable rock that bars liquids and/or gases from leaving a reservoir).[1][2][3]
Background
Petroleum systems are naturally occurring formations containing petroleum, natural gas, and other hydrocarbons (organic compounds containing carbon and hydrogen that can take the form of a solid, liquid, or gas). These systems are mapped using the principles of petroleum geology and geochemistry to locate areas with undiscovered deposits of petroleum and natural gas. The main components of a petroleum system are a source rock, a migration pathway, a reservoir, a trap, and a seal.[4][5]
- A source rock contains organic matter that will produce oil or natural gas if heated to a certain level. These rocks can include shale and limestone. The percentage of organic materials in a source rock can range from 1 percent to 10 percent. For this organic matter to generate oil and gas, it must be preserved without deterioration.[6]
- A migration pathway allows hydrocarbons to move from a source rock to a reservoir. In general, hydrocarbons have relative buoyancy (upward force acting on an object in fluid) that allows them to move from structurally low areas to high areas. A pathway can range up to hundreds of kilometers in larger sedimentary rocks.[7]
- A reservoir is a subsurface rock layer that is able to store and transfer hydrocarbons. The most common reservoirs are sedimentary rocks.[8]
- A trap is an arrangement of rocks that seal hydrocarbons within a relatively impenetrable rock formation. Traps prevent hydrocarbons from migrating to other rock layers.[9]
- A seal is a relatively impenetrable rock, such as shale or limestone, that surrounds a reservoir and prevents any liquids or gases from leaving the reservoir.[10]
See also
Footnotes
- ↑ U.S. Geological Survey, "The Total Petroleum System--The Natural Fluid Network That Constrains the Assessment Unit," 2000
- ↑ Oilfield Review, "Basin to Basin: Plate Tectonics in Exploration," Autumn 2012
- ↑ Schlumberger, "Oilfield Glossary," accessed April 27, 2014
- ↑ Schlumberger, "Petroleum system," accessed April 25, 2017
- ↑ Search and Discovery, "Petroleum Systems," accessed April 25, 2017
- ↑ Schlumberger, "Source rock," accessed April 25, 2017
- ↑ Schlumberger, "Migration," accessed April 25, 2017
- ↑ Schlumberger, "Reservoir," accessed April 25, 2017
- ↑ Schlumberger, "Trap," accessed April 25, 2017
- ↑ Schlumberger, "Seal," accessed April 25, 2017
