With half of US shale wells drilled in water-stressed areas, and the industry experiencing periodic challenges of drought even in water-rich states like Pennsylvania, E&P companies are looking to use less water in fracking operations. And more are indeed looking at using none at all.
Companies engaged in hydraulic fracturing in Kentucky and Tennessee are using nitrogen to frack wells. This article describes that process in Tennessee’s Chattanooga shale as “a substitution that works especially well in shallow formations.”
The article says that: "Further, amid spreading drought conditions across much of the U.S., along with increasing requirements that drillers treat, recycle, and reuse flowback water, the use of nitrogen in fracking is surging.”
The article is worth quoting at length:
Air Products notes that the proportion of the nitrogen used depends on a several factors, including the well's depth:
Many – if not most - of E&P companies’ costs and risks are tied to the use of water. Shale plays in nations like China, Australia, and South Africa are facing steep challenges due to a significant degree to a lack of water. And the global water cycle is increasingly disrupted as the planet warms. As I’ve argued, adding all of this up suggests a strong and growing business case for the wider use of - and perhaps conversion to - waterless fracking technologies – nitrogen, CO2, propane, propane another way, cryogenically processed methane, propellant-based, maybe exothermic fracking – and other technologies in development. Regulators should encourage - and be ready for - this shift.
The benefits of nitrogenous fracturing in times of increasing water scarcity are hardly inconsequential. For instance, whereas in recent years farmers in some parts of Colorado forked over from $9 to $100 for an acre foot of water to cities with excess supplies, energy companies are now paying $1,200 to $2,900 per acre foot.
- Nitrogen gas fracking is used in shallower formations -- typically less than 5,000 feet deep -- that are water sensitive. Since nitrogen is a , it's ideal for use in brittle shale with natural fractures that tend to stay self-propped after they've been hit by pressure pumping.
- Nitrogen foam uses 53% to 95% nitrogen, with the remainder consisting of water. Given the ability to create this combination, fluid viscosity can be adjusted as need, and the volume of additives used is reduced by the percentage of nitrogen included. The result for operators is both environmental and financial benefits.
- Nitrogen-energized fracking involves the inclusion of the gas at rates below 53% of the total. Given its increased liquids content, this combination can be used in formations with depths up to 8,000 feet.