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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 63 (1979)

Issue: 4. (April)

First Page: 697

Last Page: 698

Title: Process for Primary Migration of Petroleum in Sedimentary Basins: ABSTRACT

Author(s): E. E. Bray, W. R. Foster

Article Type: Meeting abstract

Abstract:

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Experimental data support the evolution of carbon dioxide and hydrocarbon gas concurrently with oil generation and demonstrate effective accommodation of oil in water saturated with carbon dioxide and hydrocarbon gas at the temperatures and pressures which are present at depth in source rocks. Oil carried by gas-saturated water migrating from source rocks can be unloaded in and near reservoir traps or enroute to a reservoir by removal of carbon dioxide from the water. This unloading is accomplished by reaction of carbon dioxide with "carbon dioxide-starved" or unconditioned sediments contacted by the oil-bearing water as it moves up faults and permeable strata or by coming out of solution because of low pressure at shallow depths. Carbon dioxide reactions with the source rock matrix h ve previously been saturated with the large amount of carbon dioxide generated which also provided a surplus to saturate the pore water. After the pore water is saturated with carbon dioxide, the mobilized oil can leave the source Previous HitrockNext Hit with Previous HitwaterTop expelled by compaction. In noncompacting situations the hydrocarbons can diffuse over reasonable distances from the source rocks into adjacent permeable beds.

The observed capacity of gas-saturated water to carry oil enables reasonable and available volumes of migrating water to transport and unload enough oil to fill reservoir traps.

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Copyright 1997 American Association of Petroleum Geologists