Introduction The East Texas field is now over 30 years old, having been discovered Sept. 3, 1930. This field is important because of its contribution to the law of oil proration in Texas, as well as its economic importance to Texas and to the United States. It is the largest known oil field in the U.S. by any method of comparison number of wells, area, reserves and production to date. Geographical and Structural Location The field is located on the western slope of the Sabine Uplift and the eastern side of the East Texas basin, approximately 125 miles east of Dallas. Originally it pro duoed in five Texas counties Gregg, Rusk, Cherokee, Smith and Upshur. The Smith and Cherokee wells are abandoned and production is now confined to Gregg, Rusk and Upshur Counties. Production is obtained from the Woodbine sand, Upper Cretaceous age, which is overlain unconformably by the Austin chalk except for a small area on the western side where the Eagleford shale is present. The accumulation is controlled by pinchout of the sand to the east and the occurrence of water in the Woodbine sand down dip. See Fig. 1.Maximum structural closure in approximately 230 ft from the highest structural position in the Ximines and Daniel Clark surveys, Rusk County, to the original oil-water contact of approximately 3,325-ft subsea. The Woodbine sand thickens westward to a maximum of approximately 1,000 ft in eastern Van Zandt, eastern Henderson, western Smith, and southern Wood Counties, near the center of the basin. The maximum productive thickness occurs at the line of contact of the base of the sand with the original water level, which bisects the field from north to south, with the greatest gross thickness of about 125 ft located in the northern part of the field. Source of the sediments is believed to be to the northeast, and the sand is generally finer-grained to the south. The per cent of shale in the gross section increases from approximately 15 per cent in the north to approximately 33 per cent in the south, with a weighted average of approximately 20 per cent. Development History Woodbine oil had previously been discovered along the Mexia-Powell fault zone on the Boggy Creek salt dome, and in 1929 Pure Oil Co. discovered the fabulous Van field in Van Zandt County. Although geologists knew that the Woodbine did not extend over the Sabine Uplift and strand lines were being sought in South Texas, they could not envision a field of the magnitude of East Texas. Major companies held acreage on a small surface indication of closure in the London, Tex., area and on a broad nosing east of Gladewater, Tex. The discovery well, Joiner-Daisy Bradford No. 3, was brought in on Sept. 3, 1930, after Wells 1 and 2 had failed in 1928 for mechanical reasons. The discovery' well was located in the Juan Ximines survey near the eastern edge of the field, and found the top of the Woodbine sand at a depth of 3,536 ft. On Dec. 28, 1930, the Bateman No. 1 L. D. Crim well, 10 miles to the north of the discovery, came in for 22,000 BOPD, and on Jan. 26, 1931, the Moncrief No. 1 Lathrop well 25 miles north of the discovery came in for 18,000 BOPD. All of East Texas went wild! By the end of 1931, there were 3,612 producing wells, as shown in Fig. 2. At the end of 1933 there were 11,875 producing wells owned by 1,715 different operators. In 1940 there were 971 different operators, with more than one-half having only one lease. Contrast this to Jan. 1, 1961, when there were 688 operators. The maximum number of producing wells came at the end of 1939 when 25,976 were on schedule. JPT P. 577^
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