skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Colloid transport and retention in fractured deposits. 1997 annual progress report

Abstract

'The goal of this project is to identify the chemical and physical factors that control the transport of groundwater colloids in fractured porous media and develop a generalized capability to predict colloid attachment and detachment based on hydraulic factors (head, flow rate), physical structure (fracture aperture), and chemical properties (surface properties of colloids and fracture surfaces). Understanding the processes that control colloid behavior will increase the confidence with which colloid-facilitated contaminant transport can be predicted and assessed at various contaminated US Department of Energy (DOE) sites. An added benefit is the expectation that this work will yield novel techniques to either immobilize colloid-bound contaminants in situ or mobilize colloids for enhancing remedial techniques such as pump-and-treat and bioremediation. Research Statement A series of field-scale and laboratory-scale experiments, using both natural undisturbed samples and simple one-dimension ``artificial fractures,'''' are in progress to investigate the influence of physical and chemical factors on the transport of colloids in fractured materials. The experimental results will be assessed using a computer model (COLFRAC) developed to simulate colloid transport in fractured materials. The overall goal is to assess the relative influence of chemical and physical factors expected to influence colloid transport in fractured materials and investigatemore » strategies for predictive simulation at the field scale. The experimental methods each operate at different physical/geological scales and can be used with different degrees of experimental control. This allows testing of hypotheses in a relatively simple setting in the laboratory where individual chemical or colloidal characteristics can be varied and then the results compared with field-scale experiments where the influence of realistic geologic heterogeneity can be incorporated. The work is organized into interacting tasks dealing with theoretical descriptions of colloid transport in fractures, transport studies at three spatial scales (simple one-dimensional fractures, laboratory columns of intact geological material, and field-scale colloid tracer studies), and computer modeling of colloid transport processes. A continuing iteration among all tasks and experimental scales is envisioned throughout the project. Predictions based on laboratory experiments in simplified artificial fracture systems will be tested in column and field studies, and, likewise, hypothesized interpretations of the results of the column or field studies will be tested and verified in additional laboratory studies. Experimental efforts at all scales will begin with simple binary comparisons (e.g., large vs small colloids with similar surface chemistry), and proceed with increasing complexity (e.g., varying surface properties of colloids or fractures) as understanding is developed. It is only through this parallel iteration at different scales that predictions based on laboratory understanding can be tested in column and in field studies so that additional research-can be conducted to resolve observations that were not consistent with the earlier descriptions of controlling processes.'« less

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. Oak Ridge National Lab., TN (US)
  2. Los Alamos National Lab., NM (US)
  3. Ohio State Univ., Columbus, OH (US)
  4. Tennessee Technological Univ., Cookeville, TN (US)
  5. Univ. of Tennessee, Knoxville, TN (US)
Publication Date:
Research Org.:
Oak Ridge National Lab., TN (US)
Sponsoring Org.:
USDOE Office of Environmental Management (EM), Office of Science and Risk Policy
OSTI Identifier:
13536
Report Number(s):
EMSP-55036-97
ON: DE00013536
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
58; 40; 54; 05; Progress Report; Fluid Flow; Colloids; Mechanics; Chemical Reactions; Environmental Transport; Remedial Action; High-Level Radioactive Wastes; PROGRESS REPORT; FLUID FLOW; COLLOIDS; MECHANICS; CHEMICAL REACTIONS; ENVIRONMENTAL TRANSPORT; REMEDIAL ACTION; HIGH-LEVEL RADIOACTIVE WASTES

Citation Formats

McCarthy, J.F., Reimus, P., Ibaraki, Motomu, Wells, M.J.M., and McKay, L.. Colloid transport and retention in fractured deposits. 1997 annual progress report. United States: N. p., 1997. Web. doi:10.2172/13536.
McCarthy, J.F., Reimus, P., Ibaraki, Motomu, Wells, M.J.M., & McKay, L.. Colloid transport and retention in fractured deposits. 1997 annual progress report. United States. doi:10.2172/13536.
McCarthy, J.F., Reimus, P., Ibaraki, Motomu, Wells, M.J.M., and McKay, L.. Mon . "Colloid transport and retention in fractured deposits. 1997 annual progress report". United States. doi:10.2172/13536. https://www.osti.gov/servlets/purl/13536.
@article{osti_13536,
title = {Colloid transport and retention in fractured deposits. 1997 annual progress report},
author = {McCarthy, J.F. and Reimus, P. and Ibaraki, Motomu and Wells, M.J.M. and McKay, L.},
abstractNote = {'The goal of this project is to identify the chemical and physical factors that control the transport of groundwater colloids in fractured porous media and develop a generalized capability to predict colloid attachment and detachment based on hydraulic factors (head, flow rate), physical structure (fracture aperture), and chemical properties (surface properties of colloids and fracture surfaces). Understanding the processes that control colloid behavior will increase the confidence with which colloid-facilitated contaminant transport can be predicted and assessed at various contaminated US Department of Energy (DOE) sites. An added benefit is the expectation that this work will yield novel techniques to either immobilize colloid-bound contaminants in situ or mobilize colloids for enhancing remedial techniques such as pump-and-treat and bioremediation. Research Statement A series of field-scale and laboratory-scale experiments, using both natural undisturbed samples and simple one-dimension ``artificial fractures,'''' are in progress to investigate the influence of physical and chemical factors on the transport of colloids in fractured materials. The experimental results will be assessed using a computer model (COLFRAC) developed to simulate colloid transport in fractured materials. The overall goal is to assess the relative influence of chemical and physical factors expected to influence colloid transport in fractured materials and investigate strategies for predictive simulation at the field scale. The experimental methods each operate at different physical/geological scales and can be used with different degrees of experimental control. This allows testing of hypotheses in a relatively simple setting in the laboratory where individual chemical or colloidal characteristics can be varied and then the results compared with field-scale experiments where the influence of realistic geologic heterogeneity can be incorporated. The work is organized into interacting tasks dealing with theoretical descriptions of colloid transport in fractures, transport studies at three spatial scales (simple one-dimensional fractures, laboratory columns of intact geological material, and field-scale colloid tracer studies), and computer modeling of colloid transport processes. A continuing iteration among all tasks and experimental scales is envisioned throughout the project. Predictions based on laboratory experiments in simplified artificial fracture systems will be tested in column and field studies, and, likewise, hypothesized interpretations of the results of the column or field studies will be tested and verified in additional laboratory studies. Experimental efforts at all scales will begin with simple binary comparisons (e.g., large vs small colloids with similar surface chemistry), and proceed with increasing complexity (e.g., varying surface properties of colloids or fractures) as understanding is developed. It is only through this parallel iteration at different scales that predictions based on laboratory understanding can be tested in column and in field studies so that additional research-can be conducted to resolve observations that were not consistent with the earlier descriptions of controlling processes.'},
doi = {10.2172/13536},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 1997},
month = {Mon Sep 01 00:00:00 EDT 1997}
}

Technical Report:

Save / Share:
  • 'The goal of the DOE project is to identify the chemical and physical factors that control the transport of colloids in fractured formations, and develop a generalized capability to predict colloid attachment and detachment based on hydraulic factors (head, flow rate), physical structure (fracture aperture), and chemical properties (surface properties of colloids and fracture surfaces). The research approach targets multiple scales, including: (a) a theoretical description of colloid dynamics in fractures that extend concepts used for porous media to fracture geometry, with predictions experimentally tested in simplified laboratory fractures; (b) colloid transport experiments in intact geological columns, which provide naturalmore » complexity, but mass balance data and experimental control over flow, colloid size, ionic strength and composition; (c) field-scale transport experiments using colloidal tracers to examine realistic scales of fracture connectivity; and (d) modeling of colloid transport in complex fracture networks that include fractures with varying flow rates and permitting colloid diffusion into microfractures. Understanding the processes that control colloid behavior will increase confidence with which colloid-facilitated contaminant transport can be predicted and assessed at contaminated DOE sites. An added benefit is the expectation that this work will yield novel techniques to either immobilize colloid-bound contaminants in-situ, or mobilize colloids for enhancing remedial techniques such as pump-and-treat and bioremediation.'« less
  • Understanding subsurface flow and transport processes is critical for effective assessment, decision-making, and remediation activities for contaminated sites. However, for fluid flow and contaminant transport through fractured vadose zones, traditional hydrogeological approaches are often found to be inadequate. In this project, the authors examine flow and transport through a fractured vadose zone as a deterministic chaotic dynamical process, and develop a model of it in these terms. Initially, the authors examine separately the geometric model of fractured rock and the flow dynamics model needed to describe chaotic behavior. Ultimately they will put the geometry and flow dynamics together to developmore » a chaotic-dynamical model of flow and transport in a fractured vadose zone. They investigate water flow and contaminant transport on several scales, ranging from small-scale laboratory experiments in fracture replicas and fractured cores, to field experiments conducted in a single exposed fracture at a basalt outcrop, and finally to a ponded infiltration test using a pond of 7 by 8 m. In the field experiments, they measure the time-variation of water flux, moisture content, and hydraulic head at various locations, as well as the total inflow rate to the subsurface. Such variations reflect the changes in the geometry and physics of water flow that display chaotic behavior, which they try to reconstruct using the data obtained. In the analysis of experimental data, a chaotic model can be used to predict the long-term bounds on fluid flow and transport behavior, known as the attractor of the system, and to examine the limits of short-term predictability within these bounds. This approach is especially well suited to the need for short-term predictions to support remediation decisions and long-term bounding studies. View-graphs from ten presentations made at the annual meeting held December 3--4, 1997 are included in an appendix to this report.« less
  • 'Understanding subsurface flow and transport processes is critical for effective assessment, decision-making, and remediation activities for contaminated sites. However, for fluid flow and contaminant transport through fractured vadose zones, traditional hydrogeological approaches are often found to be inadequate. In this project, the authors examine flow and transport through a fractured vadose zone as a deterministic chaotic dynamical process, and develop a model of it in these terms. Initially, they examine separately the geometric model of fractured rock and the flow dynamics model needed to describe chaotic behavior. Ultimately they will put the geometry and flow dynamics together to develop amore » chaotic-dynamical model of flow and transport in a fractured vadose zone. They investigate water flow and contaminant transport on several scales, ranging from small-scale laboratory experiments in fracture replicas and fractured cores, to field experiments conducted in a single exposed fracture at a basalt outcrop, and finally to a ponded infiltration test using a pond of 7 by 8 m. In the field experiments, the authors measure the time-variation of water flux, moisture content, and hydraulic head at various locations, as well as the total inflow rate to the subsurface. Such variations reflect the changes in the geometry and physics of water flow that display chaotic behavior, which the authors try to reconstruct using the data obtained. In the analysis of experimental data, a chaotic model can be used to predict the long-term bounds on fluid flow and transport behavior, known as the attractor of the system, and to examine the limits of short-term predictability within these bounds. This approach is especially well suited to the need for short-term predictions to support remediation decisions and long-term bounding studies.'« less
  • The goal of this project was to identify the chemical and physical factors that control the transport of colloids in fractured materials, and develop a generalized capability to predict colloid attachment and detachment based on hydraulic factors (head, flow rate), physical processes and structure (fracture aperture, matrix porosity), and chemical properties (surface properties of colloids, solution chemistry, and mineralogy of fracture surfaces). Both aqueous chemistry and physical structure of geologic formations influenced transport. Results of studies at all spatial scales reached consensus on the importance of several key controlling variables: (1) colloid retention is dominated by chemical conditions favoring colloid-wallmore » interactions; (2) even in the presence of conditions favorable to colloid collection, deposited colloids are remobilized over long times and this process contributes substantially to the overall extent of transport; (3) diffusive exchange between water-conducting fractures and finer fractures and pores acts to ''buffer'' the effects of the major fracture network structure, and reduces predictive uncertainties. Predictive tools were developed that account for fundamental mechanisms of colloid dynamics in fracture geometry, and linked to larger-scale processes in networks of fractures. The results of our study highlight the key role of physical and hydrologic factors, and processes of colloid remobilization that are potentially of even greater importance to colloid transport in the vadose zone than in saturated conditions. We propose that this work be extended to focus on understanding vadose zone transport processes so that they can eventually be linked to the understanding and tools developed in our previous project on transport in saturated groundwater systems.« less
  • The methodology and results of this project are being tested using the Andector-Goldsmith Field in the Permian Basin, West Texas. The study area includes the Central Basin Platform and the Midland Basin. The Andector-Goldsmith Field lies at the juncture of these two zones in the greater West Texas Permian Basin. Although the modeling is being conducted in this area, the results have widespread applicability to other fractured carbonate and other reservoirs throughout the world.