1 / 28

Seeing into the Earth with Hydrogeophysics : Introduction to Streaming Potential

Seeing into the Earth with Hydrogeophysics : Introduction to Streaming Potential. Defense Waste Management Programs (6210) Geophysical Research Kristopher L. Kuhlman and Bwalya Malama. Groundwater Importance. Source: Roy, Summers & Goldstein (2003). Source: economist.

mauve
Download Presentation

Seeing into the Earth with Hydrogeophysics : Introduction to Streaming Potential

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Seeing into the Earth with Hydrogeophysics: Introduction to Streaming Potential Defense Waste Management Programs (6210) Geophysical Research Kristopher L. Kuhlman and BwalyaMalama

  2. Groundwater Importance Source: Roy, Summers & Goldstein (2003) Source: economist • Largest unfrozen freshwater source • Growing Southwestern US • Use >> precipitation • Little groundwater recharge

  3. Groundwater Depletion Gravity Recovery and Climate Experiment

  4. Groundwater Flow and Transport Source: US Geological Survey • Groundwater flow • Is there enough water? • Meeting growing municipal water demand • Water rights / litigation • What is source of water? • Precipitation or infiltration • Old water from storage • Solute transport • Will contaminant migrate? • South Valley contamination • Kirtland AFB jet fuel spill • Can we clean up contamination in our lifetime? • Complexities and heterogeneities critical to transport

  5. Wells are Important & Expensive • Wells are primary access points to groundwater • Can’t measure pressure (system state) remotely • Expensive to drill/complete/maintain (often >$100k) • Collect data to maximize usefulness of wells

  6. Geophysics to the Rescue m = “Cementation exponent” n = “Saturation exponent” • Allows us to “see into the Earth” • Cheap/easy fields to measure at surface • Electromagnetic fields • X, Y & Z acceleration (seismic) • Gravitational field (microgravity) • Empirical petrophysical relations: • Geophysical properties ↔ Hydraulic properties e.g., Archie’s Law • Easy to formulate, difficult to defend physically

  7. Hydrogeophysics • Hydrogeophysics methods “directly” related to presence or movement of water in subsurface • Microgravity change due to extraction of water (mass loss) • Nuclear magnetic resonance (mobility of subsurface water) • Streaming potential due to movement of water in porous medium

  8. Spontaneous Potentials Source: wikipedia Source: fulux.com • Potentials arising “naturally” • Electrochemical potentials between • Rock types (Membrane, Nernst, or “shale” potential) • Water salinities (Liquid-junction potential) • Mineralization potential (large) • Due to redox reactions (ore bodies) • Streaming (electrokinetic) potential • voltage arising due to flow of electrolyte through porous medium with surface charge • Electrokineticforces • Electro-phoresis: movement of charged particles in fluid due to applied voltage • Electro-osmosis: flow in channel due to applied voltage (SNL microfluidics)

  9. Spontaneous Potentials Voltage Forces Process Voltage Possible coupling

  10. SP History • SP Qualitatively used to map “anomalies” • Static ore bodies (membrane/mineralization potentials) • 0.1 to 10 Volts • Transient pumping/recharge (electrokinetic potential) • 0.01 to 1 Volt Source: Bogoslovsky and Ogilvy (1972) Source: Telford et al.,(1990)

  11. Static Ion Arrangement Source: wikipedia • Individual quartz grain • Steady-state behavior • Quartz in water (pH 7) • Negative surface charge • Positive ions closest (Stern layer) • Mostly positive ions surrounding (Diffuse layer)

  12. Foundation of SP in porous media • Moving electrolyte in a pore throat • Bulk/Diffuse layer flow • Charging a RC system • Current flow proportional to water flow

  13. SP Voltage Sensors • High-impedance voltmeter • Non-polarizable single-ended electrodes • Environmental: Pb/PbCl2 • Biomedical: Ag/AgCl • Reference electrode • Sensor development work ongoing in Carlsbad

  14. SP Field Test (S. Italy) • Pumping test analysis with SP. Rizzo et al (2004) • Steady-state post-pumping only • Mostly qualitative Recovery Pumping Source: Rizzo, Suski, Revil, Straface & Troisi (2004)

  15. SP Field Test (S. Italy) • Data fit using Malama, Revil & Kuhlman (2009) model • Estimated aquifer electrical/flow properties from SP response Source: Malama, Revil & Kuhlman (2009)

  16. SP/Flow Mathematical Model • Physics-based model of coupled processes • Conservation equations • If no electro-osmosis: solve for flow problem, insert into electrical problem as source term. Darcy’s law electro-osmosis Darcy’s flux Current flux electro-kinetic Ohm’s law Charge conservation Mass conservation

  17. SP Field Test (Boise) • Unconfined test site along Boise River (Boise State Univ.) • Dipole pumping test • Dense network Observation Wells SP electrodes Source: Malama, Kuhlman & Revil (2009) Injection Well Pumping Well

  18. SP Field Test (Boise) • Updated SP model for unconfined systems • Matched entire transient dataset (not just recovery) • Estimated unconfined aquifer properties from SP data Source: Malama, Kuhlman & Revil (2009) Source: Jardani, Revil, Barrash, Crespy, Rizzo, Straface, Cardiff, Malama, Miller & Johnson (2009)

  19. SP in Granite Tunnel • SNL collaboration with Korean Atomic Energy Research Institute (KAERI) • SP test bed in fractured granite • Double-porosity system Pressure response Voltage response End pumping Begin pumping

  20. SP Falling-Head Permeameter Source: Malama & Revil (2013)

  21. Sandia SP Permeameter • Malama & Revil (2013) developed a simplified SP solution • Estimates flow/electrical properties • Simple double-exponential form • Good match to late-time permeameter data • SP voltage a viable surrogate for pressure data! • Cheaper / more robust measurements Source: Malama & Revil (2013) Clean quartz sand WIPP sand/silt Head vs. SP

  22. Sandia SP Sand Tank • Cylindrical sand tank to test theory / methods / electrodes • Controlled geometry • High instrument density • Can change aquifer material Source: Malama (2013)

  23. Sandia SP Sand Tank Source: Malama (2013)

  24. SP Lab Test (Carlsbad) Pressure Voltage (SP) • SP voltage signal • Higher signal-to-noise ratio • Easier to measure • Cheaper sensors • Measurable “at a distance” Vadose zone moisture

  25. SP Applications Source: Bogoslovsky and Ogilvy (1972) Mostly qualitative applications • Early warning system in dams • Flowing sinkhole detection • Fractures in geothermal systems (electrokinetic + thermoelectric) • Groundwater circulation near volcanoes • Seawater intrusion early warning (liquid junction potential) • Determine hydraulic properties via independent means Source: Revil, Schwaeger, Cathles & Manhardt (1999)

  26. Method Benefits / Limitations • Supplement well observations • May replace hydraulic measurements • SP sensors cheaper than pressure transducers • Easier to measure small ΔV than observe small ΔP • Earth models will make other uses quantitative • Non-conductive well casing (PVC, FRP) • Significant cultural noise • Desert soil is highly resistive, reducing surface signal • Deeper electrodes • Oscillatory/repetitive pumping (i.e., stacking) • Higher salinity → lower signal

  27. SP Future at Sandia • Sensor development • Sand tank as an SP chemistry test-bed • Upgrade permeameter for intact cores (low-Q high-P systems) • SP in rock salt • Traditional (dilute) theory predicts no signal • Strong signal seen; C(conc) needs to be investigated • Collaborate at Sandia • Electrokineticmicropumps (microfluidics 8620) • Molecular Dynamics modeling (geochemistry 6915) • Electroseismic numerical models (geophysics 6913) • Sandia advancing hydrogeophysical methods • Local applications through NM Small Business Assistance • Research / tool development through LDRD

  28. Thank You

More Related