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Water Management Techbook 2018

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40 | April 2018 | hartenergy.com WATER MANAGEMENT: BEST PRACTICES that sounds good but may not be ideal for that kind of system. That can result in issues commissioning the produced water handling system." Often when there's a problem with produced water, it manifests in the back end of the plant, Georgie said. The reality, though, is the issue could exist at any point in the process. "A common belief is whenever you have a problem with the produced water, it's blamed on the chemi- cals. So they work with the chemical companies. But the reality is that a lot of your produced water prob- lems are a result of the reservoir, the hardware, the this, the that. There are a lot of factors [from entry point to exit]," Georgie said. "Anything between here and there could have the potential for malfunction, so it's important not just to look at the back end of the plant but to look at it holistically." For example, Georgie said he's been involved with a project in Australia where the focus has been on rooting out a problem chemical. "But I don't think the chemicals are the prob- lem," he said. "Believing something is the root cause doesn't make that the case." Quality course When water for injection isn't properly treated to the quality needed, it can damage the forma- tion, Henthorne said. "There are two groups of people," Georgie said. "There are the subsurface people who deal with the reservoir. They want to use the water for operations. They need it to be clean, with no solids—absolutely crystal-clear water. In reality, that is something that cannot be delivered with a high cost from the surface people. There's a balance where you can reuse your water for unconventionals." According to Georgie, meeting the quality require- ments of the subsurface experts is "very demanding," but with a "continuous dialog between the people working the subsurface and the surface, you'll find a compromise on what kind of water quality can be delivered." Fracture-grade water—a benchmark set by the individual operators—is based on subsurface con- ditions. If a formation has fluoride, that fluoride would have to be removed from the fracture water along with the solids, Watson said. "We can make a frack fluid with any water qual- ity, but the subsurface engineers tell us not to put the solids downhole because of proppant issues," she said. There's also the question of what to do with the waste removed from cleaning up the water. The objective is to minimize waste and have water quality good enough to do the work, Watson said. Reusing produced water means having to han- dle the oil, solids, minerals and bacteria native to the water. "All those things have to be handled in one way or another to effectively recycle it without causing additional problems," Georgie said. "People think they have answers, but if you go to conferences, there are some operational issues." Georgie said the industry is working through how clean the water must be to be effective. There's a question of whether it's enough to remove only the big particles or remove most of the particles and reuse the water for use in completions. Some err on the side of maximizing the hygiene of the water, which can be cost-prohibitive, he said. "Both are manageable and sustainable, but peo- ple in the industry will take a long time to under- stand whether overdoing it gives you better results," Georgie said. There is no current standardization in the criteria for reuse of water, according to Georgie. "Everyone's doing different things," he said. If regulations aren't an issue, it will likely come down to economics. Cleaning to 50% of solids may cost 30 cents per barrel while cleaning to 99% removal of solids may cost twice that or more. A blend of produced and flowback water undergo treatment via Water Standard's mobile system. These water samples demonstrate the before and after treatment. (Photo courtesy of Water Standard)

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