A Generalized Approach to Aquifer Characterization and Uncertainty Quantification Through Oscillatory Flow Interference Testing

Jeremy Patterson

Abstract: Fractures in sedimentary bedrock aquifers act as preferential flow paths that serve to enhance mass and energy transport. Given this, extensive research efforts have been dedicated to developing methods that characterize and model fracture flow and transport in an accurate manner. Recent studies have implemented periodic pressure signals to characterize fracture flow properties; however, current analytical inversion strategies use a single stimulation frequency at a given radial distance to determine the effective fracture flow parameters in a deterministic sense. Our work proposes a gradient-based maximum likelihood inversion approach that incorporates multiple stimulation frequencies during inversion, with parameter uncertainties determined through linearized error propagation.

Using established analytical solutions, we constructed models using a fully confined (fracture bounded by impermeable bedrock) conceptualization and a leaky (fracture bounded porous media) conceptualization. Under the fully confined conceptual model, by exploring a large parameter space, we show that multi-frequency inversion reduces the size of local minima throughout the parameter space and decreases uncertainty of fracture flow parameter estimates. Under the leaky fracture conceptualization, we extend previous type curve analyses and demonstrate the ability of the proposed inversion algorithm to estimate fracture flow parameters with uncertainty comparable to the confined analysis by incorporating multiple frequencies during inversion.

Time: April 21st (10:00)

Advisor: Michael Cardiff

Co-Authors: Michael Cardiff

Stream: Zoom

Email: jpatterson7@wisc.edu