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 temperature 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, fluid flow, rock matrix chemistry, and 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 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, 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]]