AGS / Energy / Brine / Resources
Geology of Brine Resources in South Arkansas
Bromine is present in abnormally high concentrations in salt brines of the Smackover Formation (Oxfordian, Upper Jurassic) in south-central Arkansas. Bromine was originally extracted from ancient marine waters by seaweed and plankton. In Arkansas, organisms decomposed during the Jurassic period (206 to 144 million years ago) and bromine was released, leaving heavy salt concentrations called brines in Union and Columbia Counties. It is thought that brines in the Louann Salt Formation migrated through the overlying Norphlet Formation and into the Smackover Formation at a depth of 7,500 to 8,500 feet.
Schematic cross-section of a typical brine production well and basic stratigraphic relations. Note that relatively large 5 ½ inch production tubing is utilized due to the large volumes of brine that is produced. (Photo courtesy of the Albemarle Corporation).
Brine Operations in South Arkansas
When oil was discovered in south Arkansas in 1921, oil field brines were considered a worthless byproduct of drilling, and the oil producers had problems disposing of the salt water. Chemists from the Arkansas Geological Commission (now the Arkansas Geological Survey) discovered that the Smackover brines had high bromine content –4,000 to 4,600 parts per million, or about seventy times greater than that of modern ocean water. The first commercial recovery of bromine in Arkansas was from Union County in 1957, and production has been continuous since that time. Arkansas’ industry continues as the world's leading producer of bromine, averaging 40 percent of the world's production for the 5-year period between 1986 and 1990. During the same period, the average rate of growth of Arkansas' bromine recovery was more than 20 million pounds per year. U. S. production in 2001 was 212,000 metric tons, valued at $159 million, with Arkansas’ output accounting for 97 percent. Arkansas brine production for 2006 is estimated at 293,118,746 barrels according to the Arkansas Oil and Gas Commission. Bromine presently is recovered from brines in Columbia and Union Counties mainly by Great Lakes Chemical Corporation and the Albemarle Corporation.
Commercial quantities of bromine are extracted from subsurface brines at the Albemarle-Magnolia South Plant.
South Arkansas brine production wells pump brine from the Jurassic Smackover Formation that contains ~ 25 % sodium chloride (NaCl) and 3,000 – 5,000 ppm bromine. Brine supply wells are approximately 8,000 feet deep. (photo courtesy of the Albemarle Corporation)
Uses of Brine
Although there are many uses for bromine, nearly one-half of the bromine consumed annually is used in flame retardants. Other uses of bromine include medicines, insect and fungus sprays, anti-knock compounds for leaded gasoline, disinfectants, photographic preparations and chemicals, solvents, water-treatment compounds, dyes, insulating foam, hair-care products, and oil well–drilling fluids.
Elevated levels of bromine-derived chemicals have the potential to negatively affect human health. Bromine is dangerous if it comes in contact with skin, and its vapor is harmful if inhaled. For these reasons, worker safety at the commercial sites of production is monitored closely.