H34C-02
Groundwater monitoring of hydraulic fracturing in California: Recommendations for permit-required monitoring

Wednesday, 16 December 2015: 16:15
3014 (Moscone West)
Bradley K Esser1, Harry R Beller2, Susan Carroll1, John A Cherry3, Robert B Jackson4, Preston D. Jordan2, Vic Madrid1, Joseph Morris1, Beth L Parker3, William T Stringfellow2, Charukela Varadharajan2 and Avner Vengosh5, (1)Lawrence Livermore National Laboratory, Livermore, CA, United States, (2)Lawrence Berkeley National Laboratory, Berkeley, CA, United States, (3)University of Guelph, Guelph, ON, Canada, (4)Stanford University, School of Earth, Energy, and Environmental Sciences, Stanford, CA, United States, (5)Duke University, Durham, NC, United States
Abstract:
California recently passed legislation mandating dedicated groundwater quality monitoring for new well stimulation operations. The authors provided the State with expert advice on the design of such monitoring networks. Factors that must be considered in designing a new and unique groundwater monitoring program include:
  • Program design: The design of a monitoring program is contingent on its purpose, which can range from detection of individual well leakage to demonstration of regional impact. The regulatory goals for permit-required monitoring conducted by operators on a well-by-well basis will differ from the scientific goals of a regional monitoring program conducted by the State.
  • Vulnerability assessment: Identifying factors that increase the probability of transport of fluids from the hydrocarbon target zone to a protected groundwater zone enables the intensity of permit-required monitoring to be tiered by risk and also enables prioritization of regional monitoring of groundwater basins based on vulnerability. Risk factors include well integrity; proximity to existing wellbores and geologic features; wastewater disposal; vertical separation between the hydrocarbon and groundwater zones; and site-specific hydrogeology.
  • Analyte choice: The choice of chemical analytes in a regulatory monitoring program is guided by the goals of detecting impact, assuring public safety, preventing resource degradation, and minimizing cost. Balancing these goals may be best served by tiered approach in which targeted analysis of specific chemical additives is triggered by significant changes in relevant but more easily analyzed constituents. Such an approach requires characterization of baseline conditions, especially in areas with long histories of oil and gas development.
  • Monitoring technology: Monitoring a deep subsurface process or a long wellbore is more challenging than monitoring a surface industrial source. The requirement for monitoring multiple groundwater aquifers across a range of depths and of monitoring at deeper depths than is typical for regulatory monitoring programs requires consideration of monitoring technology, which can range from clusters of wells to multiple wells in a single wellbore to multi-level systems in a single cased wellbore.
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