Anahuac field is an oval-shaped oil and gas field near Turtle Bay in central Chambers County, on the coast of Southeast Texas. Its discovery and development were scientifically guided by its primary operators, Humble Oil and Refining Company, Sun Oil Company, and Gulf Oil Corporation. The field draws oil and gas from a faulted domal uplift in massive sands of the Marginulina and upper Frio formations. The source of its primary recovery was a strong water-drive and gas-cap expansion, but since April 1957 the reservoir has been maintained by reinjection into the Frio formation of all the nonassociated and most of the casinghead gas produced in the field. Between its discovery on March 6, 1935, and January 1, 1993, the field produced more than 277 million barrels of oil, and between 1974 and 1993 the field yielded more than 43.3 billion cubic feet of gas. The field is significant because the small number of operators in it followed a systematic drilling program that spaced wells for optimal oil recovery and economic return. Anahuac field was named for the county seat, situated five east of it.
In 1925 and again in 1927 and 1929 Humble Oil and Refining Company conducted early forms of geophysical measures and tests in the area of the future Anahuac field, looking for evidence of an oil-bearing structure. When geophysics offered no encouragement, Humble management allowed the company leases to expire. However, the management did not lose exploratory interest in the area. Late in 1932 Humble made a trade for the right to explore a block of 21,000 acres for thirty-five cents an acre. In the trade Humble gained the right to select any part of the acreage for drilling at five dollars an acre. In May 1933 the company used a reflection seismograph, the latest in geophysical equipment, on the block and found evidence of a structure. With these encouraging results, Humble leased three-fourths of the original block. On December 8, 1934, Humble spudded the No. 1 A. D. Middleton in Section 58, Houston and Texas Central Railway Company survey, in central Chambers County. The well had a show of high-gravity oil at the section between 7,024 and 7,050 feet in the Frio sand in February 1935. On March 6, 1935, the well reached a depth of 7,052 feet with an initial daily production of 120 barrels of oil and a gas-to-oil ratio of 12,500 cubic feet per barrel. The No. 1 Middleton was deepened to 7,088 feet on March 16, 1935, in an attempt to reduce the gas-oil ratio. From the lower depth, the well yielded 547 barrels of oil a day with an improved gas-oil ratio of 435 cubic feet to one barrel of oil.
After the success of the No. 1 Middleton, four more wells were completed in the field by early May. On May 8, 1935, the Railroad Commission of Texas set well spacing at one well to every twenty acres. At the same time the commission based production allowable 50 percent on acreage and 50 percent on well potential. On July 21 an independent partnership, Glenn H. McCarthy and R. A. Mason, brought in the No. 1 White in the James McGahey survey, with initial production of 588 barrels of oil a day, and extended the field about three miles to the north. Although nine wells were completed in the field by the end of July, it was the No. 1 White that proved the substantial size of the field and influenced leasing to the north and east. Although intense leasing drove prices as high as $1,000 an acre, the drilling of wells was cheap and quick in the new field. The average cost of drilling and completing a well to 7,100 feet was $23,000. The average time needed to drill a well through the soft sand and shale of the subsurface was twenty-one days. Even with cheap drilling costs and short drilling time, operators completed only thirty-eight wells by the end of 1935, when annual production for the field was 342,239 barrels of oil. The few operators in the field faced no competition or time constraints in field development. They chose safe locations by staking direct offsets to producing wells because they wanted an orderly development of the field and because they knew little about the producing structure.
Until the summer of 1935, when leasing excitement gripped the town of Anahuac, the county seat consisted of 200 families and few accommodations for newcomers. To meet the demand, new hotels and cafes sprouted as quickly as mushrooms after rain. Although the town had no railroad, a bus company scheduled service through Anahuac. In the field, Humble constructed a camp of twenty-five houses for employees, three warehouses, and a one-unit high-pressure pump station to carry oil through a six-inch line to its carrier in Barbers Hill oilfield and on to its Baytown refinery. In September 1935 Sun Oil Company built a four-inch pipeline in the field that eventually reached its refinery, and Gulf Production Company completed a six-inch line to run to the Hankamer field. Humble built a modern road through the field to replace an earlier wooden one. A canal was dug to supply water for the field from the Trinity River. With these new constructions, operators were set to continue field development.
During 1936, development of the field progressed with the drilling of 106 additional wells. By the end of the year only three operators were working the field, and it was estimated that 50 percent of the field was developed. Production for 1936 was 2,603,280 barrels of oil, almost 2,000 barrels below the set allowable. Although 1937 production almost doubled the 1936 figure, yields were held to just over 2.5 million barrels a year through 1940. By February 1941 Anahuac field covered 7,300 acres and Humble owned 75 percent of it. Four other companies held the remaining 25 percent. At the end of 1941, when the field reached full development, annual production was 4,649,833 barrels of oil from 356 wells and 378,438,000 cubic feet of gas from three producing wells. Annual oil production climbed during the early 1940s until peak production was reported at the end of 1944, when 11,916,137 barrels of oil were brought to the surface. Production was maintained above five million barrels of oil a year through 1975, the fortieth anniversary of the discovery of the field. By 1985, after fifty years of operation, the field gave up over 1.3 million barrels of oil annually. At the end of 1992 Anahuac field reported cumulative production of 277,086,782 barrels of oil, proving the effectiveness of the optimal oil-recovery program set in place by Humble, Sun, and Gulf fifty-seven years earlier.