Progress made in removing water soluble organics from GOM produced water

Oilfield produced water contains a diverse mixture of compounds that varies from formation to formation. Of particular importance are the organic compounds classified as “Oil and Grease” (O&G) by the Clean Water Act. O&G must be removed to meet environmental, political and operational goals. Excessive O&G in re-injected water can foul the equipment or the formation. Discharged water must meet legal or contractual standards. The O&G in water discharged to the Gulf of Mexico (GOM) is limited to a 29-mg/L yearly average. THEORY AND DEFINITIONS For the purpose of discharge, O&G is a legal category. It comprises the residue of compounds that extract into n-hexane from water at pH < 2, after boiling away the solvent.2 The EPA uses ALOLA (a lot of long acronyms) to categorize different portions of this material. The term “Water Soluble Organics” (WSO) is often used to describe the polar, non-strictly-hydrocarbon portion of the O&G compounds, which adsorb onto silica gel.