Sensitivity Assessment of Boron Isotope as Indicator of Contaminated Groundwater for Hydraulic Fracturing Flowback Fluids Produced from the Dameigou Shale of the Northern Qaidam Basin

Hydrogeochemical processes occurring in contaminated groundwater and aquifer systems may reduce the sensitivity of boron isotopes as an indicator hydraulic fracturing flowback fluids (HFFF) groundwater. In this paper, based on Chaiye-1 well (the first continental shale gas northern Qaidam Basin), hydrogeochemical affecting were analyzed HFFF-contaminated Neogene (NG1 NG2) Quaternary (QG1) around field. Then, a model for was constructed to assess HFFF indicator. The results show that, limited by range pH values saturation indices (SI) groundwater, dissolution alkali feldspar precipitation carbonate have little effect shallow For NG2 system containing clay minerals, δ11B simulated (40.0–55.6‰) is always higher than that corresponding mixed conservatively (−6.4–55.6‰) due preferential adsorption onto indicating would contamination from HFFF. scenario contamination, when mixing ratio increases 5%, detectable responses suggesting sensitive Dameigou Shale Basin.