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Federal Leasing on the Outer Continental Shelf

Booth Kellough, Offshore Exploration, Drilling and Development (1975)

The first question that should be answered before commencing any discussion of oil and gas leasing and operations on the outer continental shelf is: Where is the outer continental shelf?

Geographically, the continental shelf is the gently sloping submerged plain extending from the mean low water line of the continental shore to the point at which the plain drops sharply off down the continental slope to the true ocean floor. Usually the end of the continental shelf, where it drops off sharply enough to become the continental slope, occurs at water depths between 130 and 200 meters.1 This may occur abruptly, as in some areas offshore the coast of Maine, or as much as 200 miles from shore in some places in the Gulf of Mexico.

However, the geography of the continental shelf may have little significance in determining where it ends, since the 1958 Geneva Convention defined the seaward boundary of the continental shelf to be the 200 meter water depth contour, or beyond that limit so far as the exploitation of the natural resources of the seabed is possible.2

For example, it has recently been reported in the Oil and Gas Journal that Shell Oil Company, as operator for two groups of companies, has found oil and gas bearing sands under four tracts in 900 to 1,000 feet of water, and that Placid Oil Company plans to drill a wildcat in about 1,750 feet of water