Achieving Enhanced Treatment of Produced Fluids using Ozone, Hydrogen Peroxide and Electrochemical Oxidation: Full Scale Evaluations

The main focus of the present work was to expand the existing knowledge in using an advanced oxidation process for produced water treatment. Produced water is a phrase used in the oil and gas industry to describe water that is produced as a waste byproduct together with oil and gas. Historically produced water was pumped down disposal wells as a waste product. Due to increasing demand, limited supply and stricter regulation on fresh water sources, exploration and production companies have been compelled to recycle produced waters in many parts of their operations around the world. Produced water quality varies dramatically based on geographical location, type of hydrocarbon produced (oil or gas), and the makeup of the producing formation. In general, the total dissolved solids concentration ranges from 100,000 to over 250,000 milligrams per liter. Acid producing and sulfate reducing bacteria are the most commonly occurring microorganisms in produced water. Suspended solids, sodium, bicarbonate, chloride, iron and sulfide are the most commonly occurring inorganic constituents in produced water. Benzene, toluene, ethylbenzene, and xylene compounds are the most commonly occurring organic contaminants in produced water, which contribute to elevated chemical and biological oxygen demand. The advanced oxidation process studied in this work utilized an effective grouping of sciences to provide a high rate treatment for bacteria, organics, hydrogen and/or iron sulfide and volatile compounds; while inhibiting scale through electrochemical oxidation. Key instruments for amplification were apparent hydroxyl free radicals, and the reduction of the mass transfer resistances by efficient distribution of the ozone and hydrogen peroxide. Anticipated benefits of treatment were elimination or better compatibility with oilfield chemicals, e.g. biocides, scale inhibitors, and friction reducers. All results were correlated with oxidation-reduction potential