Hydrocarbon leakage-fill-spill patterns in the Heimdal area, Viking Graben

Abstract Two scenarios of hydrocarbon generation comprising different thermal histories and hydrocarbon potential, and six scenarios of leakage from the Jurassic into the Tertiary have been investigated using ray tracing technology. Leakage only at the Heimdal structure (Central Viking Graben) can explain all observed hydrocarbon accumulations in the Tertiary, but a scenario comprising leakage along the faults in the Heimdal area is more realistic and leads partly to a better match of phases. Preferred leakage in the Heimdal area is also compatible with mud gas concentrations observed there. The topographic differences in the Tertiary carrier are subtle. The spill pattern is complex but mainly east to west or northeast to southwest, and out of the system, with local and temporal reversal towards east and south. Oil is being spilled preferably such that trap topography is the critical variable controlling the proportions of oil and gas, and not the original gas potential in the source rock.