Paul Heller Hydrogeophysical Material Properties Lab

General Information:

The Paul Heller Hydrogeophysical Material Properties Lab, in the S.H. Knight Geology Building Room 11, contains instrumentation dedicated to developing material property transform relationships and performing experimental analyses. This facility is available for use by students in the undergraduate and graduate communities whose research calls for experimentation with Nuclear Magnetic Resonance (NMR), Ground Penetrating Radar (GPR) and DC Electrical Resistivity (DC RES). Measurement services are open for request and inquiries for instrument utilization are always welcome. The Hydrogeophysics Lab is affiliated with the UW Near Surface Geophysics Instrumentation Center (UWNSG).

Hydrogeophysics Personnel: 

Dr. Andy Parsekian: aparseki@uwyo.edu | Dr. Brad Carr: bcarr1@uwyo.edu

Laboratory Technician: Mathew Elliot: melliot@uwyo.edu

 

Lab User Request and Sample Submission Form

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Research

Here in the Hydrogeophysics Lab, we encourage innovative research ideas and applications. Whether your project is related to Arctic permafrost, Rocky Mountain hydraulic systems or any other environment on Earth, the lab strives to accommodate to the diverse research needs of the ambitious scientist. Our space provides researchers with the tools to perform sample experiments, in order to help interpret larger field-scale measurements. See also, the UW Near Surface Geophysics Instrumentation Center (UWNSG) webpage. The lab also enables users to catalog measured responses across a suite of terrestrial materials, the likeness of which, have never been measured in the same respect before. 

Some examples of past and present research utilizing the laboratory:

• Freeze/thaw experiments with GPR and NMR, differing the concentrations of H₂O and sediment
• Building Archie’s saturation vs. resistivity curves with sediment from geophysical research areas
• Student constructed time-lapse ERT systems for monitoring hillslope hydraulic response
• Measuring EM wave velocity of a plant-growing medium at varying saturations
• Gravimetric porosity measurements to compare to field-derived estimates

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Instrumentation

Electrical Resistivity: AGI Super Sting R8/IP/SP resistivity meter is available including ASTM Wenner Four-Electrode standard soil test boxes (ASTM, 2012). Arbitrarily sized columns and sample holders are also available. In conjunction with gravimetric water content measurements, this equipment may be used to calibrate Archie’s type petrophysical transformations to convert measured electrical resistivity to porosity and water saturation. These instruments may also be used to conduct 1D, 2D, or 3D lab experiments on field or synthetic samples.

Reference:

ASTM G57-06(2012), Standard Test Method for Field Measurement of Soil Resistivity Using the Wenner Four-Electrode Method, ASTM International, West Conshohocken, PA, 2012, www.astm.org

Lab-scale Ground Penetrating Radar: A Malå Geoscience (Malå, Sweden) GPR control unit with shielded, separable 1.2 GHz antennas is available for use on rectangular sample monoliths approximately 30cm in each dimension or smaller, depending on physical properties. Polycarbonate tubing with vinyl endcaps, ~7-10 cm in diameter, can also be used to encapsulate unconsolidated material. The instrument measures travel time of a transmitted electromagnetic pulse that can be converted to velocity (and relative dielectric permittivity) when distance across the sample is known. In conjunction with gravimetric water content measurements or probe measurements of dielectric permittivity, this GPR instrument can be used to calibrate empirical or physical models for saturation and porosity. This instrument can also be used in the lab for 2D or 3D tomography experiments.

Nuclear Magnetic Resonance: A Vista Clara (Mukilteo, WA) Corona NMR rock core analyzer is present that can accept either individually packed samples, or cores (in pass-through mode) ranging from smaller than 5 cm up to a maximum of 10 cm. Cylindrical plastic tubes of the aforementioned dimensions fit nicely into the Corona NMR. This instrument is housed in a Faraday cage that suppresses external radio frequency interference, therefore providing a quiet environment that ensures optimal measurements conditions. NMR is the only geophysical method that is directly sensitive to water; this laboratory instrument produces volumetric water content data as well as the transverse relaxation time that indicates pore geometry. Combining these two parameters, hydraulic conductivity may be estimated. 

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Ancillary measurements

Sample-processing equipment is also available, including: bench space, a drying oven, sample holders, graduated cylinders, polycarbonate test boxes, scales, sieves and computers containing analytical software. Shelf space and freezer space are also available in the lab for temporary sample storage. Additionally, fluid and bulk conductivity probes and dielectric probes are accessible as well.

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SOPs  

User friendly instructions are available for basic operation of the laboratory equipment. Standard operating procedures for the Corona NMR, Malå GPR and Super Sting DC RES system are available to newcomers and a straightforward gravimetric porosity SOP is available to users who wish to include that step in their sample preparation. A laboratory technician is also available by request to help users with new equipment and procedures. Once familiarized with a system, one can choose to customize a process to fit their experimental needs.