Changes

[[file:evaluating-source-rocks_fig6-19.png|300px|thumb|{{figure number|1}}Examples of yield curves for the same well, based on both open- and closed-system modeling conditions. Copyright: results of Genex 1-D basin modeling software, courtesy Institute Français du Petrole.]]

[[file:evaluating-source-rocks_fig6-19.png|300px|thumb|{{figure number|1}}Examples of yield curves for the same well, based on both open- and closed-system modeling conditions. 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).

[[: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.