Polygonal Faults and Seal Integrity

Abstract

Summary This presentation reviews the impact polygonal faults exert on seal integrity. Often invoked as a class of seal bypass system, polygonal faults are embedded into many effective seals particularly in petroleum systems in which seal and reservoir were deposited in marine slope settings. Direct evidence for the role played by polygonal faults as conduits for fluid migration is sparse. However, there are numerous examples of seismic studies of leakage via polygonal fault networks. Two end member examples are reviewed here from the Ormen Lange Field, offshore Norway, and the Scarborough Field, NW Australia. In both cases, previously formed polygonal faults in the seal acted as fluid pathways during later leakage events, and this leakage occurred under radically different pressure and stress conditions than those prevailing during the formation and growth of the polygonal faults.