Treatment of Produced Water in the Permian Basin for Hydraulic Fracturing: Comparison of Different Coagulation Processes and Innovative Filter Media

Abstract

Produced water is the largest volume of waste product generated during oil and natural gas exploration and production. The traditional method to dispose of produced water involves deep well injection, but this option is becoming more challenging due to high operational cost, limited disposal capacity, and more stringent regulations. Meanwhile, large volumes of freshwater are used for hydraulic fracturing. The goal of this study is to develop cost-effective technologies, and optimize system design and operation to treat highly saline produced water (120–140 g/L total dissolved solids) for hydraulic fracturing. Produced water was collected from a salt water disposal facility in the Permian Basin, New Mexico. Chemical coagulation (CC) using ferric chloride and aluminum sulfate as coagulants was compared with electrocoagulation (EC) with aluminum electrodes for removal of suspended contaminants. The effects of coagulant dose, current density, and hydraulic retention time during EC on turbidity removal were investigated. Experimental results showed that aluminum sulfate was more efficient and cost-effective than ferric chloride for removing turbidity from produced water. The optimal aluminum dose was achieved at operating current density of 6.60 mA/cm2 and 12 min contact time during EC treatment, which resulted in 74% removal of suspended solids and 53–78% removal of total organic carbon (TOC). The energy requirement of EC was calculated 0.36 kWh/m3 of water treated. The total operating cost of EC was estimated $0.44/m3 of treated water, which is 1.7 or 1.2 times higher than CC using alum or ferric chloride as the coagulant, respectively. The EC operating cost was primarily associated with the consumption of aluminum electrode materials due to faradaic reactions and electrodes corrosions. EC has the advantage of shorter retention time, in situ production of coagulants, less sludge generation, and high mobility for onsite produced water treatment. The fine particles and other contaminants after coagulation were further treated in continuous-flow columns packed with different filter media, including agricultural waste products (pecan shell, walnut shell, and biochar), and new and spent granular activated carbon (GAC). Turbidity, TOC, metals, and electrical conductivity were monitored to evaluate the performance of the treatment system and the adsorption capacities of different media. Biochar and GAC showed the greatest removal of turbidity and TOC in produced water. These treatment technologies were demonstrated to be effective for the removal of suspended constituents and iron, and to produce a clean brine for onsite reuse, such as hydraulic fracturing.

Oil Recovery from Oilfield Produced Water Using Zink Oxide Nano Particle as Catalyst in Batch and Continuous System

“…The oil content of the solution was 53.56 ppm. The pH of the feed tank (1) was adjusted to 6.7 by adding a diluted H 2 SO 4 solution, the appropriate amount of ZnO NPs equal to 25 mg/l was added into feed tank (1). In order to achieve consistent mixing, valve (4) was closed to allow the solution to circulate for 15 minutes.…”

“…Produced water is a by-product of gas and oil production; throughout the crude oil extraction, water rises to the surface from deep formations. The treatment processes include basic separation techniques to remove oils, grease and all suspended and solid materials, as well as advanced processes to remove inorganic ions, organic compounds and radioactive materials [1,2]. The amount of produced water ranges from 0.4 to 1.6, which is equivalent to twice the amount of oil extracted [3].…”

Suitability of water treatment chemicals in the remediation of produced water: a data-driven approach

“…Inorganic coagulants such as aluminium sulphate and ferric chloride consist of some of the most widely used coagulants for the removal of suspended and colloidal particles. Rodriguez et al (2020) stated a downside to their usage includes large masses of residual sludge and their discouraging compound to element ratio-1 ton of ferric chloride FeCl 3 •6(H 2 0) yields 210 kg of Fe(III).…”

Treatment of Produced Water with Photocatalysis: Recent Advances, Affecting Factors and Future Research Prospects

“…Contaminants in smaller amounts include dissolved gases (e.g., ammonia and hydrogen sulfide), chemical additives used to improve drilling and production operations, and naturally occurring radioactive materials leached from some formations or precipitated due to water mixing. Additionally, heavy metals and transformational byproducts that can form from the interaction between added chemicals and formation water have also been found in produced water [9,34,36]. When collecting data for its 2016 hydraulic fracturing study, the U.S. Environmental Protection Agency found literature reports of about 600 different chemicals in some produced water samples [37].…”

“…Produced water, a byproduct of oil and gas production, is water in underground formations that is brought to the surface during oil and gas production. The methods used for produced water treatment include basic separation technologies designed for the removal of total suspended solids, oil and grease, and advanced treatment technologies designed for the removal of dissolved organic compounds, inorganic ions, and radioactive materials [1][2][3][4][5][6][7][8][9][10]. Phase separation underlies basic separation technologies, such as flotation, media filtration, coagulation/flocculation, centrifugation, and hydrocyclone.…”