The Lion Oil Refining Company's Hays A-9 well, which was drilled to a depth of 7,255 feet in the SW.1/4 NE.1/4 sec. 4, T. 16 S., R. 15 W., Union County, Arkansas, is the deepest well which has been drilled in Gulf Coastal Arkansas. It was located on the highest structural point in the Graves sand in the East Smackover field and was drilled for the purpose of determining the character of the deep formations in that field. The greatest depth to which any well had previously been drilled in the field was 4,570 feet.

The test, penetrated what is believed to be the Lower Marine formation of the Trinity group of the Lower Cretaceous series and encountered rock salt at 5,960 feet. Drilling continued in the salt to 7,255 feet, penetrating a total thickness of 1,295 feet of salt. Operations were discontinued on April 12, 1932, due to the sticking of the drill stem.

Of the various hypotheses advanced to account for the salt, that which assumes that the salt occurs as a stratified deposit of earlier age than the Trinity group of beds appears to be the most tenable.

Mechanical procedure in drilling the well involved the use of eight lines, carrying an estimated maximum weight of 100,000 pounds. The net horizontal migration of the bottom of the hole at 5,164 feet was 321 feet, and the greatest inclination was 20 degrees at about 5,000 feet.

*Includes: 24 pages, 3 figures and 1 table

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