Seal and hydrocarbon yield estimates
Calibration factor
Hydrocarbon yield models estimate the volume of hydrocarbons that can be generated from a given volume of source rock and thermal history. These calculations are commonly calibrated by comparing the volume of hydrocarbons that should have been generated in a drainage area with the volume actually trapped. This “calibration factor” then is used routinely in yield estimates.
Potential errors
The logical error in many of these yield calibration studies is assuming that the hydrocarbon volume trapped is the total volume that migrated into the trap. If the trap contains a fault-dependent leak point, however, the volume that migrated in may have been much greater than the volume now trapped. The additional hydrocarbons spilled across a fault-dependent leak point and migrated updip. If these fault-dependent leak points are not identified and we assume the trap contains all the hydrocarbons generated in the source kitchen, then calibration factors and yield estimates can be extremely misleading. In addition, hydrocarbons may spill from adjacent traps rather than being directly derived from source kitchens.