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  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

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During postexpulsion migration, many processes can alter the chemical characteristics of the hydrocarbons expelled from the [[source rock]]. The geochemical similarity of reservoired hydrocarbons and hydrocarbons expelled from [[source rocks]], however, indicates there is usually little compositional alteration along the postexpulsion migration routes. An exception to this is the selective trapping of gas- and liquid-rich phases due to the quality of the seal.

During postexpulsion migration, many processes can alter the chemical characteristics of the hydrocarbons expelled from the [[source rock]]. The geochemical similarity of reservoired hydrocarbons and hydrocarbons expelled from source rocks, however, indicates there is usually little compositional alteration along the postexpulsion migration routes. An exception to this is the selective trapping of gas- and liquid-rich phases due to the quality of the seal.

==Alteration processes==

==Alteration processes==