Faults control migration and charge as well as entrapment.  Construction of migration pathway maps from fault seal analysis is as important as fault seal analysis of that major boundary fault to the prospect.

bulletSealing faults can prevent charge of a prospect/compartment
bulletPartially sealing faults can limit charge.  
bulletFaults can act as baffles to deflect hydrocarbons away from one prospect and towards another.  

Identifying a fault dependent leak point along the boundary fault of a producing field tells you that excess hydrocarbons have spilled beyond the fault.  Prospects updip off that fault dependent leak point will be charged by these spilled hydrocarbons.  The Midgard field in the Norwegian Sea is an example in which faults not only allow leakage beyond the field, but also control the direction of migration, and the ratio of oil/gas retained in the Midgard field.  Midgard is a gas field because the fault allowed only oil to migrate updip.

This is a sample   

"Hydrocarbons don't necessarily migrate into the crest of the largest structural high.  Sealing faults may trap hydrocarbons downdip and prevent charge of the obvious structural high."








Most fields are full to some fault dependent leak point.  The excess hydrocarbons have spilled updip.  The path these hydrocarbons followed and the trap subsequently charged is dependent upon the seal behavior of the intervening faults.  Map the migration pathway using routine fault seal analysis.



Migration pathway maps are not simply arrows drawn at right angles to structural contours.  A migration pathway map must include analysis of faults.  The parts of the fault that seal and the parts of the fault that leak control the migration pathway.





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