Changes

  | 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

  | 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.

==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 [[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 [[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.

==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.

For example, [[Tmax|T_max]] 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_max]] 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.

==See also==

==See also==

* [[Hydrogen Index (HI)]]

* [[Hydrogen Index (HI)]]

* [[Production Index (PI)]]

* [[Production Index (PI)]]

==External links==

==External links==

[[Category:Critical elements of the petroleum system]]  

[[Category:Critical elements of the petroleum system]]  

[[Category:Evaluating source rocks]]

[[Category:Evaluating source rocks]]