Secondary hydrocarbon migration under hydrostatic conditions

1 Secondary hydrocarbon migration under hydrostatic conditions 

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Figure 4.4 Secondary separate phase hydrocarbon migration under hydrostatic conditions (after Hobson and Tiratsoo, 1975. Reprinted by permission of Scientific Press Ltd.).

Under hydrostatic conditions the basin-wide secondary hydrocarbon migration patterns and consequently also the final distribution of the oil and gas accumulations in a sedimentary basin are closely linked to the stable basin geometry present during hydrocarbon expulsion from the source rocks. 

The process of migration may lead to focussed movement of hydrocarbons into economic accumulations. The secondary migration of hydrocarbons may occur under hydrostatic or hydrodynamic conditions. Under hydrostatic conditions, the hydrocarbons migrate through the water-saturated carrier-reservoir rocks as separate phase hydrocarbons. Under hydrodynamic conditions, the hydrocarbons may be transported in continuous separate phase, in suspension or in aqueous solution. Under both hydrostatic and hydrodynamic conditions, the hydrocarbons ultimately appear as separate phase hydrocarbons before they can accumulate in a trap (Tissot and Welte, 1984). 

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