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| | part = Critical elements of the petroleum system | | | part = Critical elements of the petroleum system |
| | chapter = Evaluating source rocks | | | chapter = Evaluating source rocks |
− | | frompg = 6-1 | + | | frompg = 6-22 |
− | | topg = 6-41 | + | | topg = 6-22 |
| | author = Carol A. Law | | | author = Carol A. Law |
| | link = http://archives.datapages.com/data/specpubs/beaumont/ch06/ch06.htm | | | link = http://archives.datapages.com/data/specpubs/beaumont/ch06/ch06.htm |
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| | isbn = 0-89181-602-X | | | isbn = 0-89181-602-X |
| }} | | }} |
− | The chemistry of organic matter contained within a sedimentary rock changes over time, reflecting its [[Thermal history|thermal]] and [[burial history]]. This change or maturation is measured and can be combined with quality and richness data to gauge the amount of hydrocarbon generated by the organic matter. The present-day maturity level is the product of a number of variables, such as [[tectonic setting]], [[burial history]], and [[thermal history]]. A number of variables such as [[paleolatitude]], pressure, [[Wikipedia:Fluid dynamics|fluid flow]], rock matrix chemistry, and [[Petroleum reservoir fluid properties|pore fluid chemistry]] can affect the thermal history and thus a rock's rate of maturation. | + | The chemistry of organic matter contained within a sedimentary rock changes over time, reflecting its [[Thermal history|thermal]] and [[burial history]]. This change or maturation is measured and can be combined with quality and richness data to gauge the amount of hydrocarbon generated by the organic matter. The present-day maturity level is the product of a number of variables, such as [[tectonic setting]], burial history, and thermal history. A number of variables such as [[paleolatitude]], pressure, [[Wikipedia:Fluid dynamics|fluid flow]], rock matrix chemistry, and [[Petroleum reservoir fluid properties|pore fluid chemistry]] can affect the thermal history and thus a rock's rate of maturation. |
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| ==Transformation rate== | | ==Transformation rate== |
− | The rate at which hydrocarbons are generated from [[organic matter]] is called the ''transformation rate''. Using [[source rock]] maturity, we can estimate the transformation rate. Different [[kerogen types]] (1) generate hydrocarbons at different maturity levels and (2) have different transformation rates. Maturity measurements can be made on several different components of a rock like [[vitrinite]], kerogen, [[spore]]s, [[apatite]] grains, and [[biomarker]]s; each has its own relationship to the kerogen transformation rate. | + | The rate at which hydrocarbons are generated from [[organic matter]] is called the ''transformation rate''. Using [[source rock]] maturity, we can estimate the transformation rate. Different [[kerogen types]] (1) generate hydrocarbons at different [[Kerogen types: comparison of maturity measures|maturity levels]] and (2) have different transformation rates. Maturity measurements can be made on several different components of a rock like [[Thermal maturation#Vitrinite|vitrinite]], [[kerogen]], [[spore]]s, [[apatite]] grains, and [[biomarker]]s; each has its own relationship to the kerogen transformation rate. |
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| ==Caveat== | | ==Caveat== |
| Evaluating the maturation of a geologic section is based on a depth trend from samples in a well or basin. The level of maturity interpreted from most maturation indices is dependent on the type of organic matter or material being analyzed. | | Evaluating the maturation of a geologic section is based on a depth trend from samples in a well or basin. The level of maturity interpreted from most maturation indices is dependent on the type of organic matter or material being analyzed. |
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− | For example, [[Tmax|T<sub>max</sub>]] cutoffs for hydrocarbon-generation zones are greater for type III than for type II kerogen. Therefore, a trend is only valid if based on analysis of samples from a homogeneous organic sequence or if differences in chemistry are accounted for in the interpretation process. | + | For example, [[Tmax|T<sub>max</sub>]] cutoffs for [[Petroleum generation|hydrocarbon-generation]] zones are greater for type III than for type II kerogen. Therefore, a trend is only valid if based on analysis of samples from a homogeneous organic sequence or if differences in chemistry are accounted for in the interpretation process. |
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| ==See also== | | ==See also== |
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| * [[Hydrogen Index (HI)]] | | * [[Hydrogen Index (HI)]] |
| * [[Production Index (PI)]] | | * [[Production Index (PI)]] |
| + | * [[Kerogen type and maturity]] |
| + | * [[Kerogen types: comparison of maturity measures]] |
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| ==External links== | | ==External links== |
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| [[Category:Critical elements of the petroleum system]] | | [[Category:Critical elements of the petroleum system]] |
| [[Category:Evaluating source rocks]] | | [[Category:Evaluating source rocks]] |
| + | [[Category:Treatise Handbook 3]] |