Four appraisal wells drilled during 1971–1972 revealed a large reservoir at a depth of about 7000 feet and closure of 155 m. Hill, P.J., and Wood, G.V., 1980, Geology of the Forties Field, U.K. Continental Shelf, North Sea, in Giant Oil and Gas Fields of the Decade:1968-1978, AAPG Memoir 30, Tulsa: American Association of Petroleum Geologists, , p. 81.