Drilling and completing natural gas wells using modern multi-stage fracturing techniques in reserves like NuVista’s may require significant volumes of water. The volume of water used depends on using the fracturing method best suited to the reservoir. NuVista is committed to reduce the impact of its water use by pursuing techniques that increasingly reduce, re-use and recycle the water required to drill our wells.
Simply put, we are committed to constant improvement as we push toward our goals of using less fresh water, seeking non-potable sources, recycling to the maximum extent possible, and disposing of as little water as possible. At every new field location we conduct testing and validation, and we install facilities so we can continually minimize or even eliminate the use of fresh water. Not only does this approach minimize environmental impacts, it also has the potential to reduce costs.
NuVista evaluates the use of alternative water-source options to reduce fresh water use wherever possible. For example, NuVista actively conducts evaluations and tests on potential water sources from brackish and deep saline-water formations well below the freshwater aquifers that are used for drinking water and agriculture. Although brackish and saline water sources are not available for every well, NuVista actively targets and evaluates alternative water source options to reduce the use of fresh water. We also cooperate with service providers and industry peers to source brackish and saline water outside of our immediate areas of operations.
Technological advances also provide an opportunity to reduce water usage. NuVista invests in industry-leading, proven technologies like nitrogen foam fracturing that reduce the volume requirement of water during hydraulic fracturing by as much as 85% while also potentially leading to higher natural gas recoveries. As the most plentiful element in the earth’s atmosphere, nitrogen is a safe and abundant potential replacement for water in well stimulation.
NuVista continues to collaborate with industry partners to exploit new opportunities to share and re-use water. For example, NuVista has sourced saline water from sweet flowback operations of industry partners to supplement water volumes required for hydraulic fracturing. On individual wells NuVista has obtained up to 45% of the water volumes required for well stimulation from brackish and saline water sources. Our use of brackish and saline water is in line with long-term industry trends towards using more saline groundwater and less fresh groundwater.
The presence of sour gas in our produced water and flowback makes for significant safety and technological challenges in order to re-use our produced water. NuVista continues to evaluate potential solutions and conducts technology trials on an ongoing basis to find feasible, safe treatments of sour fluid in hydraulic fracturing.
Safe handling and disposal of this sour fluid is paramount to our operations. At NuVista’s Wapiti field we have invested in drilling a deep disposal well to deposit waste water in formations more than 1,000 metres below fresh water aquifers. We’re also working on building pipelines to gather and transfer produced water safety and economically within our field operations.