MESOZOIC CARBONATE HYDROCARBON POTENTIAL BALTIMORE CANYON US OFFSHORE EAST COAST

Hydrocarbon exploration in the Baltimore Canyon during the 1980’s targeted Upper Jurassic and younger clastics and carbonates in stratigraphic traps consisting of possibly erosionally enhanced mounds and pinnacles. Five wells encountered hydrocarbons with cumulative flow rates testing 90 mm cfg/d. Apparent discontinuity in reservoir extent resulted in project abandonment. Highly mature, organic source rocks in this area were not identifi ed. A recent organic reinterpretation of gas condensates from the Hudson Canyon suggests a deeper Lower Jurassic source, analogous to that of the U.S. Gulf Coast’s Smackover Formation, Late Jurassic in age.

The Houston Oil Minerals 676 Well encountered salt at a depth of 3,800 meters on the eastern fl ank of the Schlee Dome. Reprocessed seismic data (AVO Analysis) indicate refl ectors typical of widespread salt layers deposited during the Early Jurassic (60 m thick and25 km wide) suggesting arid and restricted (anoxic) depositional climatic conditions in the Early Jurassic. Impermeable evaporites and shales, between the Lower and Upper Jurassic, may provide excellent seals explaining the lack of significant migration of hydrocarbons into porous rocks of the Upper Jurassic and Cretaceous. The Gulf Coast Smackover may be an excellent analog for this area. The RedSea-Dead Sea-Sea of Galilee rift zone may be an important modern analog for the Baltimore Canyon Trough. Carbonates in this area have porosities that range between 30% and 60% permeabilities that range between 0.01 and 10,000 millidarcys.

The thermal maturation profile (based on the Shell 273-1 well) for the Baltimore Canyon Trough indicates that Jurassic age sedimentsentered the early oil phase at a depth of approximately 2500 m and the main gas generation window at a depth of 5000 m. Gas generation in Early to Middle Jurassic sediments started in the Late Jurassic and continued through the Tertiary.Sediments younger than the Early Cretaceous are not thermally mature. Reservoirs should be in carbonates and shelf clastics. An isopach map of the Baltimore Canyon Trough indicates that a signifi cant area of Jurassic Age sediments, greater than 6 km thick, is buried to depths of mature hydrocarbon.