Some Needs and Potential Benefits Related to aNational Underground Science LaboratoryNUSLGeo-HydrologyEngineering-Team OverviewScientific RationaleSocietal ImperativesScience and Engineering NeedsApproachAnticipated Benefits

Scientific RationaleSocietal Imperatives

Resource RecoveryPetroleum and Natural Gas Recovery in Conventional & Unconventional ReservoirsIn Situ MiningHDR/EGSPotable Water SupplyMining HydrologyWaste Containment/DisposalDeep Waste InjectionNuclear Waste DisposalCO2 SequestrationCryogenic Storage/Petroleum/GasSite RestorationAcid-Rock DrainageAquifer Remediation

Scientific Rationale (Contd)Science & Engineering Needs

1.Mechanical & Transport Behavior (momentum, fluid, mass, & energy fluxes)2.Solid- and Fluid-Environment Interaction3.Characterization of Mechanical and Transport Properties4.Sensing, Data Fusion, and ModelingNatural fractureArtificial fracture

Scientific & Engineering Issues Needed to Address Societal Needs

Science & Engineering Needs (Contd)

1. Mechanical and Transport BehaviorConnectivity of Fracture NetworksMulti-phase FlowParticulate (Colloid/Bacterial) Transport

PercolationRemote SensingSolute flux(Dagan et al. 1992)

PercolationAfter Pyrak-Nolte et al., 1990Glass 1992

Science & Engineering Needs (Contd)

2. Solid- & Fluid-Environment InteractionModels of Fracture DevelopmentCoupled ProcessesTHMCBTHMCB

800C1200C1200C1500C800C

Importance of Large-Scale In-Situ Experiments Validation of coupled reaction-transport conceptual and numerical models requires well-controlled in-situ experiments (not found in nature)Effective reaction rates are controlled by the hierarchy of scale of fluid flow - e.g., flow in a fracture, through the fracture network, and flow between the rock matrix and the adjacent fracturesReaction-transport processes can be strongly coupled to permeability changes from rock mechanical processes and can affect rock deformation as a result of changing mineralogy, permeability, and the chemical environment at fracture tipsThe Drift-Scale Test at Yucca Mountain has been used to study coupled thermal-hydrological-chemical-mechanical processes in unsaturated fractured tuffHowever, different geological and chemical environments can result in different system evolutions

Example of thermal-hydrological-chemical processes in boiling unsaturated fractured rock

Coupled Thermal, Hydrological, and Chemical Processes in the Drift Scale Test at Yucca MountainPurpose of the test is to evaluate coupled thermal, hydrological, mechanical and chemical processes surrounding the potential repositoryDimensions: ~ 50 meters long by 5 meters in diameterElectric heaters activated Dec. 1997, turned off Jan. 2002Maximum drift wall temperature reached ~ 200CWater, gas, and rock samples collected from boreholes for geochemical and isotopic studiesReaction-transport modeling performed prior to and during test (examples on following slides)

Mineral Precipitation in the Drift Scale Test Mineral precipitation/dissolution in fractures is strongly coupled to heat transport and the migration of water in fractures via gravity drainage and capillary suction (amorphous silica and calcite examples, below) Numerical models can only be fully validated by in-situ experiments on the appropriate spatial (tens of meters) and temporal scales (> 1 year)

CO2 Evolution in the Drift Scale Test CO2 concentrations in vapor migrating through fractures reflects coupled processes of boiling, vapor condensation, diffusion and reaction of flowing fracture water with calcite coatings on fracture walls Reactive transport models using alternative geochemical systems are tested against measured gas concentrations (figure on right)

Science & Engineering Needs (Contd)

3. Characterization of Mechanical & Transport PropertiesHydraulic MethodsTracer MethodsNaturalForcedAqueous (Conservative/Reactive)ThermalParticulateGeophysical MethodsDrilling Methods

Vertical fractures Constant OrientationAVAZ predicted orientationMinimum and maximum AVO effect directionAnisotropic AVO theory

But there is no theory to predict what would happen to AVO response when there are dipping fractures or multiple fracture sets.

0%7%We think that this image might be telling us something about fracture orientations and intensity, but it is not clear what

What we would like to be able to do is to accurately infer the fracture pattern, so that wells could be sited and completed to enhance numerous recovery processes

Geophysical Methods - Waterflood Acoustic Events

Science & Engineering Needs (Contd)

4. Sensing, Data Fusion, and ModelingSensingData FusionModeling

Science & Engineering Needs (Contd)

ImperativesStrong scale dependenceTHMCB processes incompletely understoodThe role of serendipity in scientific advanceApproachRun-of-Mine Experiments (HCB)Experiments Concurrent with Excavation of the Detector Caverns (THM)Purpose-Built Experiments (THMCB)Large Block TestsMine-By and Drift Structure TestsEducational Opportunities

How Key Science & Engineering Issues May Be Addressed by Underground Science Laboratory Experiments

Science & Engineering Needs (Contd)

Anticipated Benefits and ApplicationsResource Recovery and SecurityWaste Containment/DisposalSite RestorationEducation

Fracture strain maps show similar trends to velocity anisotropy maps.