The Washburn anticline trends east-west for 40 mi and covers at least 157 sq mi within 6,000 ft of closure. Commercial quantities of gas were discovered on the feature in 1954. Since then sporadic drilling has resulted in 31 gas wells, spaced on 640-acre governmental sections, and 12 dry holes. The Gragg, Booneville, and Chismville gas fields are all on surface expression of the Washburn anticline.

Production is essentially dry methane gas from at least 15 sandstone beds within the middle and lower parts of the Atoka Formation. Open-flow potentials range from less than 1 million to 33.5 million cu ft of gas a day with shut-in pressures of from 355 to 2,912 psi. Most of the wells in Chismville, T. 6 N., R. 27 W., and Booneville, T. 6 N., R. 28 W., were connected in 1961. The Gragg wells, in T. 6 N., Rs. 29, 30 W., were connected in June 1964. Arkansas-Louisiana Gas Company is the only purchaser from these fields.

The approximately 11,700 ft of the Atoka Formation at Washburn is subdivided into zones which can be recognized in most wells. Lenticularity of sandstone bodies and marked variation in porosity and permeability in the gas zones reflect the unstable shallow-basin environment in which the sands were deposited. Rocks of the Morrow Series have been tested in three wells, but were found nonproductive. There is one deep Arbuckle (Cambrian-Ordovician) test on structure. This well was dry in all of the pre-Atoka rocks at a total depth of 12,505 ft.

Strike-thrust faults, trending east-west near the crest of Washburn, complicate the structure. Nearly every well has cut at least one thrust fault with displacement commonly being between 1,000 and 1,500 ft.

It appears that the three gas fields on the anticline will ultimately be joined into one large gas field.