The Lisbon oil field, in Claiborne and Lincoln parishes, Louisiana, was discovered in December, 1936. From present information, it appears that the localization of oil is controlled by the lenticular development of porosity in the Patton limestone which flanks the south edge of a broad structural nose. Production is obtained from the Patton limestone zone of lower Glen Rose age at an average depth of 5,200 feet. The effective porosity of the Lisbon producing zone is highly variable in thickness, varying from 4 feet to 22 feet, with an average of 12.6 feet. The daily field allowable is 10,000 barrels based on 3,252 developed acres as defined by the Louisiana Conservation Department. The field produced 2,405,000 barrels from 150 wells during 1937.

The original gas-oil ratios were very low, varying from 50 cubic feet to 300 cubic feet per barrel; consequently, no separators were used. With a rapid decline in bottom-hole pressures, the gas-oil ratios have shown a proportional increase. However, most wells have a ratio less than 2,000 cubic feet to the barrel at present. There are no established gas or water levels despite apparent interzone communication within the Patton limestone. It is the writers' opinion that the thickness and the areal extent of the "Oakes" limestone zone are the factors, independent of structure, which will control future developments of the Lisbon field.