Determination of Water Saturation Using Gas Phase Partitioning Tracers and Time‐Lapse Electrical Conductivity Measurements

Water saturation is an important indicator of contaminant distribution and plays a governing role in contaminant transport within the vadose zone. Understanding the water saturation distribution is critical for both remediation and contaminant flux monitoring in unsaturated environments. In this work we propose and demonstrate a method of remotely determining water saturation levels using gas phase partitioning tracers and time-lapse bulk electrical conductivity measurements. The theoretical development includes the partitioning chemistry for the tracers we demonstrate (ammonia and carbon dioxide), as well as a review of the petrophysical relationship governing how these tracers influence bulk conductivity. We also investigate methods of utilizing secondary information provided by electrical conductivity breakthrough magnitudes induced by the tracers. We test the method on clean, well characterized, intermediate-scale sand columns under controlled conditions. Results demonstrate the capability to predict partitioning coefficients and accurately monitor gas breakthrough curves along the length of the column according to the corresponding electrical conductivity response, leading to accurate water saturation estimates. This work is motivated by the need to develop effective characterization and monitoring techniques for contaminated deep vadose zone environments, and provides a proof-of-concept toward uniquely characterizing and monitoring water saturation levels at the field scale and in three-dimensionsmore » using electrical resistivity tomography.« less

[1]  Roelof Versteeg,et al.  Improved hydrogeophysical characterization and monitoring through parallel modeling and inversion of time-domain resistivity andinduced-polarization data , 2010 .

[2]  M. H. Waxman,et al.  Electrical Conductivities in Oil-Bearing Shaly Sands , 1968 .

[3]  Alberto Villa,et al.  Calibration of a Vadose Zone Model Using Water Injection Monitored by GPR and Electrical Resistance Tomography , 2008 .

[4]  G. E. Archie.  The electrical resistivity log as an aid in determining some reservoir characteristics , 1942 .

[5]  L. N. Plummer,et al.  The solubilities of calcite, aragonite and vaterite in CO2-H2O solutions between 0 and 90°C, and an evaluation of the aqueous model for the system CaCO3-CO2-H2O , 1982 .

[6]  M. Karaoulis,et al.  Review: Some low-frequency electrical methods for subsurface characterization and monitoring in hydrogeology , 2012, Hydrogeology Journal.

[7]  Alberto Villa,et al.  An experiment of non‐invasive characterization of the vadose zone via water injection and cross‐hole time‐lapse geophysical monitoring , 2007 .

[8]  M. Fayer,et al.  An automated tool for three types of saturated hydraulic conductivity laboratory measurements , 2009 .

[9]  W. J. Greenwood,et al.  Geochemical and Geophysical Changes during Ammonia Gas Treatment of Vadose Zone Sediments for Uranium Remediation , 2012 .

[10]  A. Binley,et al.  Imaging Brilliant Blue Stained Soil by Means of Electrical Resistivity Tomography , 2009 .

[11]  Susan S. Hubbard,et al.  Monitoring Vadose Zone Desiccation with Geophysical Methods , 2013 .

[12]  C. Ulrich,et al.  Induced polarization measurements on unsaturated, unconsolidated sands , 2004 .

[13]  John S. Selker,et al.  Characterization of Miller‐Similar Silica Sands for Laboratory Hydrologic Studies , 1996 .

[14]  Mark L. Brusseau,et al.  Characterizing gas-water interfacial and bulk-water partitioning for gas-phase transport of organic contaminants in unsaturated porous media , 1997 .

[15]  A. Binley,et al.  A saline trace test monitored via time-lapse surface electrical resistivity tomography. , 2006 .

[16]  Michael Whitfield,et al.  A chemical model of seawater including dissolved ammonia and the stoichiometric dissociation constant of ammonia in estuarine water and seawater from −2 to 40°C , 1995 .

[17]  A gas‐phase partitioning tracer method for the in situ measurement of soil‐water content , 1999 .

[18]  L. Slater,et al.  IP interpretation in environmental investigations , 2002 .

[19]  H. Vinegar,et al.  Induced polarization of shaly sands , 1984 .

[20]  David P. Lesmes,et al.  Dielectric spectroscopy of sedimentary rocks , 2001 .

[21]  J. J. Renard,et al.  Fate of ammonia in the atmosphere--a review for applicability to hazardous releases. , 2004, Journal of hazardous materials.

[22]  G. Gee,et al.  Hydrologic Characterization Using Vadose Zone Monitoring Tools: Status Report , 2003 .

[23]  L. Wilson,et al.  Handbook of Vadose Zone Characterization & Monitoring , 1994 .

[24]  Mark L Brusseau,et al.  In-situ characterization of soil-water content using gas-phase partitioning tracer tests: field-scale evaluation. , 2003, Environmental science & technology.

[25]  M. Oostrom,et al.  Sensor and Numerical Simulator Evaluation for Porous Medium Desiccation and Rewetting at the Intermediate Laboratory Scale , 2012 .

[26]  K. Cantrell,et al.  Review: Technical and policy challenges in deep vadose zone remediation of metals and radionuclides. , 2011, Environmental science & technology.

[27]  S. J. Cyvin,et al.  Equilibrium Constants in the Ammonium Carbonate--Carbaminate System. The Acid Dissociation Constant of Carbamic Acid. , 1978 .

[28]  J. Nitao,et al.  Electrical resistivity tomography of vadose water movement , 1992 .

[29]  M. Maeder,et al.  Kinetics of the reversible reaction of CO2(aq) with ammonia in aqueous solution. , 2011, The journal of physical chemistry. A.