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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 67 (1983)

Issue: 3. (March)

First Page: 490

Last Page: 490

Title: Clay Mineral Catalysis and Petroleum Generation: ABSTRACT

Author(s): W. D. Johns

Article Type: Meeting abstract


Kerogen, the major organic component of sediments and sedimentary rocks, is the immediate precursor of petroleum hydrocarbons. Recent studies of kerogen maturation during burial diagenesis show that decarboxylation of fatty acid constituents and C-C bond cleavage of hydrocarbon groups, both attached to the kerogen polymer, lead ultimately to petroleum-hydrocarbon formation. The low temperature range over which this occurs (60 to 110°C, 140 to 230°F) has suggested that the clay mineral matrix may play a role in catalyzing these important reactions.

Kinetic studies of clay-organic reactions have demonstrated the effectiveness of clay catalysis in organic acid decarboxylation and cracking reactions and suggest the mechanisms involved.

Kinetic constants deduced for these reactions from the natural maturation of kerogen during diagenesis reveal a further complication in sediments. Because kerogen is a solid, relatively immobile polymer, structural rearrangement is necessary to bring reacting groups in contact with catalytic sites. Mechanical movement plays a role in promoting catalytic activity.

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Copyright 1997 American Association of Petroleum Geologists