Hydraulic tomography: 3D hydraulic conductivity, fracture network, and connectivity in mudstone
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- Data Release: USGS data release - MODFLOW-2005 and MODPATH models used to simulate hydraulic tomography pumping tests and identify a fracture network, former Naval Air Warfare Center, West Trenton, NJ
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Abstract
We present the first demonstration of hydraulic tomography (HT) to estimate the three-dimensional (3D) hydraulic conductivity (K) distribution of a fractured aquifer at high-resolution field scale (HRFS), including the fracture network and connectivity through it. We invert drawdown data collected from packer-isolated borehole intervals during 42 pumping tests in a wellfield at the former Naval Air Warfare Center, West Trenton, New Jersey, in the Newark Basin. Five additional tests were reserved for a quality check of HT results. We used an equivalent porous medium forward model and geostatistical inversion to estimate 3D K at high resolution (K blocks <1 m3), using no strict assumptions about K variability or fracture statistics. The resulting 3D K estimate ranges from approximately 0.1 (highest-K fractures) to approximately 10−13 m/s (unfractured mudstone). Important estimated features include: (1) a highly fractured zone (HFZ) consisting of a sequence of high-K bedding-plane fractures; (2) a low-K zone that disrupts the HFZ; (3) several secondary fractures of limited extent; and (4) regions of very low-K rock matrix. The 3D K estimate explains complex drawdown behavior observed in the field. Drawdown tracing and particle tracking simulations reveal a 3D fracture network within the estimated K distribution, and connectivity routes through the network. Model fit is best in the shallower part of the wellfield, with high density of observations and tests. The capabilities of HT demonstrated for 3D fractured aquifer characterization at HRFS may support improved in situ remediation for contaminant source zones, and applications in mining, repository assessment, or geotechnical engineering.
Study Area
Publication type | Article |
---|---|
Publication Subtype | Journal Article |
Title | Hydraulic tomography: 3D hydraulic conductivity, fracture network, and connectivity in mudstone |
Series title | Groundwater |
DOI | 10.1111/gwat.12915 |
Volume | 58 |
Issue | 2 |
Year Published | 2020 |
Language | English |
Publisher | National Ground Water Association |
Contributing office(s) | WMA - Earth System Processes Division |
First page | 238 |
Last page | 257 |
Country | United States |
State | New Jersey |
Other Geospatial | Naval Air Warfare Center |
Google Analytic Metrics | Metrics page |