Produced Water Reuse for Drilling and Completion Fluids Using Ion Exchange Resins

Abstract

Produced water is considered one of the largest by volume waste streams and one of the most challenging effluents in the oil and gas industry. This is due to the variety of contaminants that make up produce water. A variety of treatment methods have been studied and implemented. These methods aim to reduce the hydrocarbon content and the number of contaminants in produced water to meet the disposal, reuse, and environmental regulations. These contaminants can include dispersed oil droplets, suspended solids, dissolved solids, heavy metals, and other production chemicals. Some of those contaminates have value and can be a commodity in different applications such as bromine (Br). Bromine ions can be used to form calcium bromide, which is considered one of the most effective drilling agents and is used extensively in drilling and completion operations. This paper aims to highlight the utilization and the new extraction method of bromide ions from produced water to form calcium bromide (CaBr2). The conventional preparation of calcium-bromide drilling and completion fluids involves adding solid calcium-bromide salts to the water, which can be relatively expensive. Another method can involve the handling of strong oxidants and toxic gas to form solid calcium bromide. The novel method outlined in this paper is a cost-effective and environmentally friendly way of generating calcium bromide from produced water. The method includes processing the produced water to recover bromide ions. This is done by first passing the produced water through a resin bed, including bromine-specific ion exchange resin, where the bromide ions will adsorb/absorb onto the resin, as shown in Figure-1. The second step involves regenerating the resin with regenerant having calcium cations and water to form calcium bromide. The final stage is generating the calcium bromide in the water from the bed of resin by introducing concentrated CaCl2, forming a concentrated solution of water and calcium bromide. The developed solution will be further processed to give drilling and completion fluids. This novel method constitutes a good example of produced water utilization in different applications to minimize waste and reduce the costs of forming highly consumable materials.