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Open- vs closed-system generation modeling (view source)
Revision as of 13:58, 24 January 2014
, 13:58, 24 January 2014Initial import
{{publication
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Critical elements of the petroleum system
| chapter = Evaluating source rocks
| frompg = 6-1
| topg = 6-41
| author = Carol A. Law
| link = http://archives.datapages.com/data/specpubs/beaumont/ch06/ch06.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
Hydrocarbon generation results from computerized 1-D basin [[modeling]] software are typically presented as either open- or closed-system yields. '''Open-system''' models are based on the assumption that hydrocarbons have been expelled from the source rock, have been transported away, and are no longer subject to the thermal conditions of the 1-D model. '''Closed-system''' models assume the hydrocarbons have not been expelled from the source rock and that all generated hydrocarbon phases are subject to further cracking to lighter phases.
==Implications for yield predictions==
Below are examples of yield curves for the same well, based on both open- and closed-system modeling conditions. The open-system model is run with an expulsion efficiency of 70%, meaning 70% of the generated hydrocarbons were expelled before subsequent maturation and were not subjected to secondary cracking to lighter phases. The closed-system model does not incorporate an expulsion component; therefore, the hydrocarbons are subject to cracking to lighter phases. The closed-system model (right) predicts significantly greater quantities of gas at depth than the open-system model (left).
[[file:evaluating-source-rocks_fig6-19.png|thumb|{{figure number|6-19}}. Copyright: results of Genex 1-D basin modeling software, courtesy Institute Français du Petrole.]]
'''Note:''' In general, open-system models overestimate the quantities of liquids present in a system. Closed-system models overestimate the amount of gas present in the system and are pessimistic in terms of predicting quantities of liquids. Closed-system models typically are not run any more. However, when evaluating older models, consider this effect.
==See also==
* [[Relationships between maturity and hydrocarbon generation]]
* [[Kerogen type and hydrocarbon generation]]
* [[Kerogen type and maturity]]
* [[Kerogen type and transformation ratio]]
* [[Comparison of kerogen types]]
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch06/ch06.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Critical elements of the petroleum system]]
[[Category:Evaluating source rocks]]
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Critical elements of the petroleum system
| chapter = Evaluating source rocks
| frompg = 6-1
| topg = 6-41
| author = Carol A. Law
| link = http://archives.datapages.com/data/specpubs/beaumont/ch06/ch06.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
Hydrocarbon generation results from computerized 1-D basin [[modeling]] software are typically presented as either open- or closed-system yields. '''Open-system''' models are based on the assumption that hydrocarbons have been expelled from the source rock, have been transported away, and are no longer subject to the thermal conditions of the 1-D model. '''Closed-system''' models assume the hydrocarbons have not been expelled from the source rock and that all generated hydrocarbon phases are subject to further cracking to lighter phases.
==Implications for yield predictions==
Below are examples of yield curves for the same well, based on both open- and closed-system modeling conditions. The open-system model is run with an expulsion efficiency of 70%, meaning 70% of the generated hydrocarbons were expelled before subsequent maturation and were not subjected to secondary cracking to lighter phases. The closed-system model does not incorporate an expulsion component; therefore, the hydrocarbons are subject to cracking to lighter phases. The closed-system model (right) predicts significantly greater quantities of gas at depth than the open-system model (left).
[[file:evaluating-source-rocks_fig6-19.png|thumb|{{figure number|6-19}}. Copyright: results of Genex 1-D basin modeling software, courtesy Institute Français du Petrole.]]
'''Note:''' In general, open-system models overestimate the quantities of liquids present in a system. Closed-system models overestimate the amount of gas present in the system and are pessimistic in terms of predicting quantities of liquids. Closed-system models typically are not run any more. However, when evaluating older models, consider this effect.
==See also==
* [[Relationships between maturity and hydrocarbon generation]]
* [[Kerogen type and hydrocarbon generation]]
* [[Kerogen type and maturity]]
* [[Kerogen type and transformation ratio]]
* [[Comparison of kerogen types]]
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch06/ch06.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Critical elements of the petroleum system]]
[[Category:Evaluating source rocks]]