title: Assessing hydrofracing success from earth tide and barometric response.
abstract: Identifying fracture pathways and connectivity between adjacent wells is vital for understanding flow characteristics, transport properties, and fracture characteristics. In this investigation, a simple, straightforward methodology is presented for assessing hydrofracing success and identifying possible fracture connectivity between neighboring boreholes, using water-level barometric response and tide signatures of individual fractures in a crystalline-rock setting. Water levels and barometric pressure heads were collected at two wells 27 m apart both prior to, and after, hydrofracing one of the wells at the fractured-rock research site in Floyd County, Virginia. Vastly different barometric and tidal signatures existed at the two wells prior to hydrofracing as well EX-1 had no discernable fractures, while W-03 was connected to an identified fault-zone aquifer and produced a notable water-level earth tide and barometric signatures. After hydrofracing EX-1, new fractures were induced and the resulting water-level tidal signature and barometric efficiencies were nearly identical to the W-03 well. Aquifer testing conducted from both wells verified this connectivity along the fault-zone aquifer. The small phase difference between the tidal responses in the two wells can be accounted for by the calculated differences in transmissivity and casing diameter.
authors.affiliation: Department of Geosciences, Virginia Tech, Blacksburg, VA 24061, USA. tjburbey@vt.edu
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Burbey
authors.forename: Meijing
authors.initials: M
authors.lastname: Zhang
mesh_terms: D001274:Atmospheric Pressure; D004784:Environmental Monitoring / Q000379:methods*; D014768:Virginia; D014872:Water Movements; D014881:Water Supply