Page 93 - Occupational Health & Safety, June 2019

OIL & GAS
Four Steps to Quickly Evaluate Produced Water Reuse Option Viability
After it has been determined what waste water reuse options are physically possible and affordable, the viability determination isn’t over until the regulatory, environmental, and social impacts have been determined.
BY LAURA SLANSKY
www.ohsonline.com
JUNE 2019 | Occupational Health & Safety 89
Produced water management can be a bur- densome task to a producer. Some estimates suggest water management is up to 25 per- cent of the expense of a well in its lifetime.
It often requires trucking through populated areas, exposure of employees or contractors to hazardous chemicals, and it generates public suspicion. In some areas of the United States, but not for all, water dis- posal through injection is an expensive, ineffective method. There are fields in the United States where disposal by injection is a very limited option due to seismicity concerns or capacity issues. Pennsylvania has only 11 permitted produced water wastewater disposal wells in 2017.
The American Geosciences Institute (AGI) re- ports 90 percent of produced water volume is dis- posed of by injection well. This is a potential resource that the industry should consider viewing as an asset
instead of a waste. In order to do so, produced water reuse options warrant an occasional viability review, even if produced water disposal by injection is avail- able and affordable.
Produced water reuse and recycling options have become more economic, available, and necessary. This is driven by four factors: more open political climate allowing reuse, the need to restrict fresh water use, the prohibition or over-capacity issues of disposal by in- jection in some areas, and the advancing technologies available for both water treatment and possible reuse in completions fluid formulas.
Periodic assessment of produced water reuse op- tions is a valuable economic tool with sustainable re- source benefits. It is important to know what reuse is locally available, what the requirements are to meet the reuse, and what water quality is available in the field. These parameters are ever-changing, so periodic evaluation of reuse viability is a smarter option than permanent dismissal of a reuse idea.
To begin a viability assessment, it is important to start with an accounting of the entire life-cycle: resources used, material processed, transportation costs, human factors, and waste produced. Start to de- velop any possible products that can be derived. The AGI estimates that less than 1 percent of produced water is used outside the oilfield, yet there are signifi- cant industrial needs for large water volumes in many industries—be open to any new reuse idea and try to look for the potential benefit. Once an outline of po- tential reuse options is developed, the viability assess- ment can begin.
Step One: Evaluate the Waste Water
In order to evaluate the types of possible reuse, the waste water characteristics must be determined: water volumes, physical water characteristics, and chemical water characteristics. Begin a sampling plan through- out the field. Collect produced water samples from ev- ery type of source in the field: flowback, at the tanks, at SWDs, etc., ideally after the water has settled.
Make sure to sample at multiple periods in a well’s lifespan. The intention is to have a solid idea of waste water patterns, both chronologically in a well’s lifespan and geographically in the field. Make sure physical water characteristics (temperature, density,
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