Abstract The Old Ocean field, in the prolific Frio producing trend, is one of the largest and most important gas fields on the Texas Gulf Coast. Oil first was discovered in November 1934 as a result of reflection- seismograph surveys. Most production from the field is from four major reservoirs, all of Frio age. Two of these are characterized by huge gas caps with oil rims. The other two are primarily gas and condensate reservoirs. The field is on a large asymmetrical dome which probably is the result of deep-seated salt movement. Accumulation and entrapment are anticlinal. The two upper reservoirs have gas-expansion drive and no effective water drive. The lower reservoirs are of the simple volumetric-depletion type. Original reserves in place are estimated to have been 4,466,000 million cu ft of gas, 198,200,000 bbls of condensate, and 276,400,000 bbls of oil. The average daily oil production, as of January 1, 1966, was 5,945 bbls of liquids from the field, 13,001 bbls of liquids from the plant, and approximately 15,239 million cu ft of gas, of which 6,493 million cu ft was used in pressure maintenance of two of the reservoirs. Net daily withdrawal was approximately 8,746 million cu ft of gas. Accumulative gas production to January 1, 1966, was 3,307,856 million cu ft of gas, of which 1,575,384 million cu ft was net after 1,736,472 million cu ft had been reinjected for pressure maintenance and cycling. Deeper possibilities to 15,000 ft have been explored, perhaps efficiently, by a single dry hole. However, possibilities remain for production below this depth if favorable sandstone conditions are found.