Chloride concentration gradients in tank-stored hydraulic fracturing fluids following flowback

Abstract

A natural gas well in West Virginia was hydraulically fractured and the fl owback was recovered and stored in an 18-foot-deep tank. Both in situ fi eld test kit and laboratory measurements of electrical conductivity and chloride concentrations increased substantially with depth, although the laboratory measurements showed a greater increase. The fi eld test kit also underestimated chloride concentrations in prepared standards when they exceeded 8,000 mg L -1 , indicating that laboratory analyses or other more accurate methods of detection should be used to determine chloride concentrations in fl owback when they may be approaching West Virginia regulatory levels (12,500 mg L -1 ) that disallow disposal by land application. The gradation of chloride with depth also has implications for procedures used to collect fl owback samples from reserve pits or tanks before disposal to ensure the resulting composite chloride concentration is representative of the total volume. Cover PhotoWilliam Wilson uses a fi eld kit to determine the chloride concentrations of a fl owback sample. Photo by Pamela Edwards, U.S. Forest Service.The use of trade, fi rm, or corporation names in this paper is for the information and convenience of the reader. Such use does not constitute an offi cial endorsement or approval by the U.S. Department of Agriculture or the Forest Service of any product or service to the exclusion of others that may be suitable.

Tidal Response of Groundwater in a Leaky Aquifer—Application to Oklahoma

“…Since the USGS deep monitoring well is cased from the surface to the top of the Arbuckle aquifer (Figure 5), water in the well comes solely from the Arbuckle aquifer. This measured specific electrical conductivity of the groundwater is within the range for freshwater, which is unexpected because it is at least an order of magnitude lower than the specific electrical conductivity of the flow-back fluids injected at the well before the USGS operation started (e.g., Edwards, et al, 2011;Li, et al, 2014). Two mechanisms may have operated to dilute the concentration of the injected fluid.…”

Sustainable Management of Flowback Water during Hydraulic Fracturing of Marcellus Shale for Natural Gas Production

“…Based on extended DLVO theory, which takes steric repulsion forces into consideration for particle-particle interactions, once polymer or NOM is coated on particle surface, repulsion forces between particles are largely increased, thereby increasing the stability of coated colloidal or nano-sized particles (Hotze et al, 2011;Pincus, 1991). Scaling inhibitors and friction reducers, which are injected together with hydrofracturing water (Edwards et al, 2011;EPA, 2011), as well as natural organic matter from the shale matrix could be responsible for such behavior (Groundwater Protection Council, 2009).…”