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Line 17: − 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). − + + +
Open- vs closed-system generation modeling (view source)
Revision as of 19:25, 28 January 2014
, 19:25, 28 January 2014no edit summary
==Implications for yield predictions==
==Implications for yield predictions==
[[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.]]
[[file:evaluating-source-rocks_fig6-19.png|thumb|{{figure number|1}}. Copyright: results of Genex 1-D basin modeling software, courtesy Institute Français du Petrole.]]
[[:file:evaluating-source-rocks_fig6-19.png|Figure 1]] shows 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).
'''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.
'''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.