Permeability Super Highway Primer, page-2

"The Ellesmerian(!) petroleum system of the North Slope, Alaska, contains approximately 77 billion bbl of oil equivalent (Bird, 1994). The age of the reservoir rock ranges from Mississippian to early Tertiary. Total organic carbon and assumed hydrogen indices from the marine shale source rocks indicate the mass of petroleum generated to be approximately 8 trillion barrels of oil (Bird, 1994). These estimates indicate about 1% of the generated hydrocarbons are contained in known traps. More importantly, the U.S. Geological Survey estimates another 1% is trapped in undiscovered accumulations in the Ellesmerian(!) petroleum system (Bird, 1994)."​

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