Russell T. Johns (rjohns@mail.utexas.edu) is the Program Manager of the Fundamental Processes research program.
Research on Fundamental Processes examines the intersection of fluid mechanics, thermodynamics, surface science, transport phenomena, geochemistry and petrophysics that determines the flow and transport properties of geological formations, oil and gas reservoirs and aquifers.
Research Projects
Mechanisms Leading to Co-Existence of Gas and Hydrate in Ocean Sediments - Steven L. Bryant, Ruben Juanes (MIT)
Funding source: U.S. Department of Energy
Funding amount: $1,074,000 for the period of Oct. 2006 - Sept. 2010
This project seeks to quantify how methane is distributed and transported within a hydrate resource area. In concept, methane is transported when gas pressure builds up until it fractures the sediment; water and gas then move into the fracture, the gas drains into the sediment, and hydrate forms at the gas/water interfaces. Researchers will model fracture initiation and propagation as well as the geometry of gas/water interfaces, coupling the two models to help simulate a mechanism for how gas and hydrate coexist. The resulting model would be an important step toward characterizing and predicting the behavior of active vs. stable hydrate deposits, and it will help us better understand the complex systems containing hydrate, water, free gas, and sediment. Please see the Methan Hydrate Project page for more information.
Displacements at Sharp Interfaces (Non-Equilibrium Flow) - David DiCarlo
When one fluid displaces another inside a porous media, the sharpness of the wetting front can determine the stability of the overall displacement. Also inherently, displacements with sharp fronts cannot be modeled using continuum multi-phase flow equations. Qualitatively the sharpness can be explained by a competition between two different pore-filling mechanisms (called snap-off and piston-like). Previous infiltration experiments with water have shown that there exists a transition flux, where below this flux snap-off filling dominates, and above piston-like collective filling dominates. Integral to this competition is the formation of wetting layers (small conduits in the corners and edges of the pore-space) ahead of the main wetting front. We are using experimental 1-D displacements and dynamic network modeling to study the creation of these wetting layers and their affects on the dynamics of the wetting front. Origin of Scale-Dependent Dispersivity and Its Implications for Miscible Gas Flooding - Steven L. Bryant, Russell T. Johns, Larry W. Lake
Funding source: U.S. Department of Energy
Funding amount: $800,000 for the period of Oct. 2004 - Oct. 2007
This research will use microsensors to measure pore-level mixing in porous rocks under conditions related to the use of carbon dioxide and solvents. The improved understanding of mixing phenomena is needed to increase the oil recovery from depleted oil reservoirs at low cost using advanced methods of oil recovery.
Influence of Grain-scale Geometry on Colloid Transport - Steven L. Bryant
Funding source: U.S. Department of Agriculture
Funding amount: $246,000 for the period of Sep. 2004 - Aug. 2007
Water resources and environmental quality are important issues for agriculture. A key component of water quality is the concentration of very small (colloidal) particles suspended in the water. Example particles are bacteria, viruses and inorganic materials on which contaminants have adsorbed. Colloids can be trapped or retained by soil grains as water carries them through the soil, with profound implications for water quality. Historically this retention is attributed to two mechanisms, filtration and straining. But many researchers have reported behavior that does not fit this classification: colloids theoretically too small to be strained are nevertheless retained, even when filtration is negligible. This project seeks to explain these observations.The hypothesis underlying this research is that colloid straining occurs not just in pore throats but also in small gaps between pairs of grains. To test the hypothesis, this project will develop a quantitative analysis of the geometry of these gaps. The approach is predictive, relying on a novel class of model soils that are geometrically determinate and physically representative. We will adapt techniques for computing flow through the pore space of the model soils to determine fluxes through individual gaps. Incorporating the local distribution of flow through gaps into an existing theory of straining will enable testing the model against experiments reported in the literature. Because the approach involves no adjustable parameters, the results will contribute to the scientific basis for water resources stewardship.
Multi-Scale Flow and Transport Modeling of Large-Vug Cretaceous Carbonates - Todd Arbogast (Math), Steven L. Bryant, Jim Jennings (Bureau of Economic Geology), Charlie Kerans (Bureau of Economic Geology)
Funding source: National Science Foundation
Funding period: Sep. 2004 - Aug. 2007
In previous work we developed tools to model and compute flow at the meter scale in rocks containing touching cm-scale vugs. In this project, we will address the questions of 1) solute transport in such systems and 2) the extension of the models to the 1 to 10 meter scale, and then to the 100 meter macro-scale. We will take advantage of a unique opportunity to construct models that accurately represent the spatial distribution of vugs at multiple length scales and that account for the appropriate physics of flow and transport by combining expertise in laboratory and field measurement, model building, and computation. Our experimental studies will be based on the Pipe Creek Reef outcrop in Central Texas.
Theoretical Evaluation of the Interfacial Area Between Two Fluids in Soil (EPA, NSF, VIGRE) - Steven L. Bryant
Modeling Flow in Porous Media with Vugular Meso-Scale Heterogeneities (NSF) - Steven L. Bryant
Investigation of Three-Phase Flow in Miscible Gas Floods (ACS) - Russell T. Johns
Related Research
Improved Oil Recovery Efficiency by Gas Injection (ATP) - Russell T. Johns, Larry W. Lake
Naturally Fractured Reservoirs - Jon E. Olson (info available at Dr. Olson's home page)
Related CPGE research programs:
Proposed Research
Smart Fluids - Quoc P. Nguyen
Polymer and polymer gels have long been used in improved oil recovery, near wellbore treatments, and environmental remediation. A major drawback of using polymeric systems is a high risk of damaging the formation, due primarily to a strong adsorption of the polymers. Viscoelastic surfactants recently developed not only overcome this problem, but also exhibit more advantages. For example, self-diversion of acid to the desired areas. However, the development of these "smart" fluids has not advanced far enough to ensure its successful performance under high temperature, high shear rate, presence of third phases (oil, solid particle), and for a wide variation of rock physicochemical properties. This is most likely due to the fact that the mechanisms acting for structural aggregate formation in porous media are poorly understood. This proposed project is aimed at developing a mechanistic rheological model for viscoelastic surfactants in different flow geometries, based on the molecular design. The main concern is the formation and stability of surfactant aggregates in disordered pore networks, including the effect of polymeric additives in maintaining the viscoelasticity at elevated temperatures.
Predictive Pore-level Modeling for Flow and Transport Processes - Steven L. Bryant
Advanced Fractional-Flow Methods - Russell T. Johns, Larry W. Lake
Three-Phase Pore Network Modeling - Russell T. Johns
Integrated Compositional and Foam Simulation for Gas Flooding - Russell T. Johns, Gary A. Pope
Scaling Laws for Dispersion in Porous Media - Sanjay Srinivasan and Larry W. Lake
Influence of Geological Heterogeneity on Flow - Sanjay Srinivasan
Virtual Petrophysical Measurements: Using Model Rocks to Quantitatively Predict Macroscopic Transport Coefficients (Relative Permeability, Resistivity, Acoustic Velocity) - Steven L. Bryant