EOR Economics Improved with Innovation in Produced Water Desalination
May 7, 2018
Saltworks successfully tested Flex EDR advanced electrodialysis reversal technology to treat produced water at an enhanced oil recovery (EOR) site in Alberta, Canada. The field pilot proved that desalting EOR produced water can provide a substantial return on investment, helping to make water treatment a profit center rather than a cost center.
Polymer flood EOR sites add costly polymer to recycled produced water before it is re-injected. This polymer makes injected water more viscous, or thick, and pushes out more oil. Salinity of the water, however, increases polymer consumption considerably, and this can cost millions of dollars per year. The field pilot reported as much as 50% savings on polymer costs and 90% freshwater recovery by leveraging Flex EDR’s ability to desalinate the produced water with minimal pre-treatment. This outcome pays for the cost of desalination, and offers oil & gas companies the opportunity to reduce their costs, withdraw less make-up water, and improve oil recovery.
The mobile water treatment plant operated continuously over a 60-day period with 95% uptime to desalinate produced water. The system successfully treated produced water with highly variable oil-in-water concentrations, enabled by Saltworks’ IonFlux exchange membranes used in the Flex EDR treatment stack. This desalinated produced water could then be used for reinjection and required far less make-up polymer to achieve the same viscosity, resulting in the substantial cost savings. Beneficially, some of the polymer in the produced water remained in the desalinated stream for reuse.
The Flex EDR system is an advanced electrodialysis reversal (EDR) system that utilizes next generation ion exchange membranes that are designed and manufactured by Saltworks. The desalination system can withstand highly variable water chemistries with little pre-treatment while desalinating water containing harsh oils and organics. It can also tune produced water to specific salinity levels while decreasing the hardness of the treated stream. This is of interest to oil companies since the best injection waters have almost no hardness (Ba, Ca, Mg), but some trace salinity (Na, Cl).
Saltworks Director of Technology, Derek Mandel, commented that, “We look forward to taking this successful pilot to the next level with a full-scale EOR water treatment plant. Our results suggest companies practicing chemical flooding stand to slash their operating costs and reduce their water usage; Flex EDR is a win-win for chemical EOR.” Read the article that was published today in Industrial WaterWorld that outlines additional details about the pilot. A Society of Petroleum Engineers (SPE) paper was also published on this topic earlier this month – please contact Saltworks for access to a copy.