Frack Water Solutions
The role of water in hydraulic fracturing operations
Water use in unconventional shale oil and gas extraction can be complicated. The hydraulic fracturing process can use more than 5 million gallons of water per well, and water to support unconventional shale oil and gas production can come from a variety of conventional sources, including fresh or brackish waters from surface or groundwater withdrawal, treated wastewaters and recycled water produced along with oil and gas.
Water sourcing and water management decisions associated with shale oil and gas development fall into two primary categories: water utilization within hydraulic fracturing operations and the disposal of wastewater from drilling and production. Keystone has been established to take advantage of the latter – the disposal and treatment of wastewater from the Keystone impoundment facility. After the completion and stimulation of shale oil and gas wells, fracturing flowback water, the portion of injected hydraulic fracturing fluids that return to surface before production, returns to the surface quickly over a few weeks and shows a rapid decline in quantity and quality (typically 10-30% returns in the first 1-2 weeks). Flowback water often contains very high total dissolved solids (TDS) and is characterized by the presence of sand, clays, polymers, heavy metals and chemistry associated with the drilling and completion of the new well. Shale produced water (i.e. water produced during oil and gas production), on the other hand, requires management in the longer term. Produced water flow rates are typically much lower and more consistent than flowback, are variable field-to-field and well-to-well but have generally predictable flow rates and quality.
Among the concerns from an industry perspective is the availability of sustainable water management solutions to manage the rapid development of shales and other tight oil and gas resources
Flowback and produced water
After the process of hydraulic fracturing is complete and the gas reservoirs are opened, down-hole pressures push a percentage of the hydraulic fracturing fluid back to the surface. This flowback water contains hydrocarbons, minerals, residual hydraulic fracturing chemistry and other substances originating from the shale itself. Flowback water must be collected and securely contained before it is either recycled or disposed. Measures are also taken to prevent circumstances in which flowback or produced water is discharged to the environment or to municipal wastewater treatment plants prior to significant treatment. The variable and short-term nature of flowback water makes treatment technically and logistically challenging.
To date, much of the flowback and produced water have been stored in centrally located water impoundment facilities containing millions of gallons of water. Existing technologies to treat flowback water to be recycled into the next hydraulic fracturing job, remove contaminants before disposal and improve water quality to meet discharge and re-use standards have been inadequate or costly.
Due to limited disposal options, the shale gas industry has adapted a practice of recycling "dirty" frack water to drill new wells. Over time, this practice causes an increase in the contaminant concentration levels making the frack water even more difficult to dispose of.
Keystone safely and efficiently eliminates impurities and restores water, kills bacteria, removes heavy metals, and reduces hardness. Keystone enables operators to reuse flowback and produced water -- saving costs by using less water and minimizing disposal expenses.
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