Changes

==Compositional changes and correlation==

==Compositional changes and correlation==

Expulsion favors [[light compounds]] over [[heavy compounds]] and [[saturated hydrocarbons]] over [[Wikipedia:Aromatic hydrocarbon|aromatics]]. This is due to [[molecular filtering]] and [[adsorption]]–[[desorption]] phenomena, particularly during the early stages. However, because significant quantities of hydrocarbons are retained in the large and medium [[Pore system fundamentals|pore systems]] within the source rock, the correlation of reservoired oil with its respective source rock is not significantly affected (see also [[Oil-oil and oil-source rock correlation]]. The effect of continued [[maturation]] of the source rock after expulsion is a more significant impediment to correlation.

Expulsion favors [http://www.glossary.oilfield.slb.com/en/Terms.aspx?LookIn=term%20name&filter=light%20hydrocarbons light compounds] over heavy compounds and [http://www.chemistry-dictionary.com/definition/saturated+hydrocarbons.php saturated hydrocarbons] over [[Wikipedia:Aromatic hydrocarbon|aromatics]]. This is due to [[Wikipedia:Molecular sieve|molecular filtering]] and http://www.merriam-webster.com/dictionary/adsorption [adsorption]–[http://en.wiktionary.org/wiki/desorption desorption] phenomena, particularly during the early stages. However, because significant quantities of hydrocarbons are retained in the large and medium [[Pore system fundamentals|pore systems]] within the source rock, the correlation of reservoired oil with its respective source rock is not significantly affected (see also [[Oil-oil and oil-source rock correlation]]. The effect of continued [[maturation]] of the source rock after expulsion is a more significant impediment to correlation.

==See also==

==See also==