Thermohaline Flow and Reactive Solute Transport in Fractured Rock

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1 Thermohaline Flow and Reactive Solute Transport in Fractured Rock Thomas GRAF Institute of Fluid Mechanics in Civil Engineering

Alberta Geological Survey, Edmonton 2008-2009 Basin Hydrogeologist Sasdf sdaf df Sadf Université Laval, Quebec 2002-2005 Ph.D.

2 Alberta Geological Survey, Edmonton Basin Hydrogeologist Sasdf sdaf df Sadf Université Laval, Quebec Ph.D PostDoc Fsda Sdaf» sfda Title Leibniz Universität Hannover since 2009 Professor Georg-August Universität Göttingen Research Fellow Albert-Ludwigs Universität Freiburg 2001 Diploma in Hydrology Flinders University, Adelaide Exchange Student 2005 Visiting Scientist

3 Outline Work Area Mathematical Methods Research Group Student Projects My Ongoing Projects Outlook 3 / 50

4 Work Area Coupled Geo-Processes FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 4 / 50

5 Work Area 1. Heterogeneity FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 5 / 50

6 Work Area 2. Open Fractures FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 6 / 50

7 Work Area 3. Variable Topography / Unsaturated Soil FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 7 / 50

8 Work Area 4. Heat Source FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 8 / 50

9 Work Area 5. Saline Brine FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 9 / 50

10 Work Area 6. Variable-Density Free Convection FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 10 / 50

11 Work Area 7. Sealevel Variations / Flooding / Surface Flow FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 11 / 50

12 Work Area 8. Dissolution / Precipitation of Quartz FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 12 / 50

13 Research Applications Climatic Change - Geothermal Energy - Radioactive Waste CO2 - etc. FLOODING SURFACE FLOW VADOSE ZONE SEALEVEL VARIATIONS SEAWATER ρ sea FRACTURES PHREATIC ZONE HETEROGENEITY Na-Ca-Cl MAGMA (Heat Source) 13 / 50

14 Work Goal Understand flow dynamics including coupled geo-processes 14 / 50

15 THMC - Coupled Processes 15 / 50

16 THMC - Coupled Processes 16 / 50

HydroGeoSphere Attempt to account for relevant geo-processes in a numerical model Therrien and Sudicky (1996, J Cont Hyd) Numerical groundwater

17 HydroGeoSphere Attempt to account for relevant geo-processes in a numerical model Therrien and Sudicky (1996, J Cont Hyd) Numerical groundwater model using Control- Volume Finite Element (CVFE) method Developed in Canada (Waterloo, Québec) Co-developer since 2003 OpenGeoSys, TOUGH2 17 / 50

18 Outline Work Area Mathematical Methods Research Group Student Projects My Ongoing Projects Outlook 18 / 50

$matrix 2D: rock fractures 1D: wells, channels Irregular$ mesh 3D: blocks, prisms, tetrahedrons 2D: rectangles,

efficient) t L+ 1 X = max X max L+ 1 i X L i

flow Variably saturated flow (Richards Equation; Newton

19 HydroGeoSphere Features Multi-dimensional model 3D: rock matrix 2D: rock fractures 1D: wells, channels Irregular mesh 3D: blocks, prisms, tetrahedrons 2D: rectangles, triangles 1D: lines Variable time-stepping (very efficient) t L+ 1 X = max X max L+ 1 i X L i Multi-species solute transport, heat transfer, fluid flow Variably saturated flow (Richards Equation; Newton Iteration) Variable-density variable-viscosity flow (Picard Iteration) t L 19 / 50

HydroGeoSphere Features 2D overland flow

$fracture and matrix Reaction parameters are$

20 HydroGeoSphere Features 2D overland flow (Diffusion-wave equation) Reactive transport with quartz chemistry Dissolution and precipitation Widening and sealing of fracture and matrix Reaction parameters are fully temperature-coupled SiO 2(s) + 2H O 2 (aq) H 4 SiO 4(aq) 20 / 50

21 HydroGeoSphere Features Upstream and central weighting of velocities Various time weighting schemes (explicit, Crank-Nicolson, implicit) Full fracture-matrix coupling Discrete fracture approach (DF) Dual continuum approach (DC) Equivalent porous medium approach (EPM) DF DC EPM common nodes (1 unknown) exchange term high K 21 / 50

$complete hydrologic cycle matrix nodes surface nodes fracture nodes$

22 HydroGeoSphere Features Fully integrated numerical solution of complete hydrologic cycle matrix nodes surface nodes fracture nodes 22 / 50

23 Numerical Coupling Initial C σ, T next time step no threshold exceeded? update material properties yes N iterations = 0 reduce t repeat timestep reactive TRANSPORT N iterations += 1 Picard Iteration no convergence AND N iterations > 1 yes update fluid properties ρ, µ Newton T C σ FLOW Iteration HEAT TRANSPORT P DARCY q 23 / 50

24 Outline Work Area Mathematical Methods Research Group Student Projects My Ongoing Projects Outlook 24 / 50

25 My Vision 25 / 50

26 Emmy Noether Group DFG funded Nov present years 4 research positions (PhD) 2 MSc projects International team 26 / 50

27 Outline Work Area Mathematical Methods Research Group Student Projects My Ongoing Projects Outlook 27 / 50

28 Double-Diffusive Convection Katharina Vujević 28 / 50

29 Double-Diffusive Convection salt Katharina Vujević heat T1, C1 T2, C2 T2, C3 well mixed fluid layers 29 / 50

30 Double-Diffusive Convection Form of layers geometry of fracture network? Information of fracture network geometry? Katharina Vujević??? 30 / 50

Coastal Flow Dynamics Jie Yang http://www.

31 Coastal Flow Dynamics Jie Yang 31 / 50

32 Coastal Flow Dynamics Jie Yang Changing flow boundary conditions Surface flow Variable-density flow Variably saturated flow Climatic change Freshwater Salt water 32 / 50

33 Coastal Flow Dynamics Jie Yang Changing flow boundary conditions Surface flow Variable-density flow Variably saturated flow Climatic change Freshwater Salt water 33 / 50

34 Coastal Flow Dynamics HydroGeoSphere model Preliminary results Jie Yang 34 / 50

35 3D Fractured Rock Eugenia Hirthe 35 / 50

$3D Fractured Rock Eugenia Hirthe Time truncation error control Role of fracture aperture Role of$

36 3D Fractured Rock Eugenia Hirthe Time truncation error control Role of fracture aperture Role of fracture connectivity in 2D / 3D Role of small / large fractures Which degree of complexity is necessary? 36 / 50

37 OB Assumption Oberbeck-Boussinesq Assumption (OBA=1,2,3) Carlos Guevara OBA reflects mathematical accuracy of density consideration OB1 (lowest accuracy) OB3 (highest accuracy) Many simulations of variable-density flow use OB1 or 2. Impact of OBA is unclear. 37 / 50

38 OB Assumption OB Flow Eq. Transport Eq. Darcy Eq. Carlos Guevara 1 ( q) = 1 ρ ( ρφ) t ( j) = ( φω) t q = k μ ( p + ρg z) 2 ( ) ( φω ( ) ( ρφ) ) k ρq = j = q = ( p + ρg z) t t μ 3 ( ρq) = ( ρφ) t ( ρj) = ( ρφω) t q = k μ ( p + ρg z) 38 / 50

39 Viscosity Variation µ varies with T by one order of magnitude. µ is often assumed constant in studies of variable-density flow. µ affects flux because K = kρg / µ. Qiang Sun viscosity [10-3 kg m -1 sec -1 ] brine seawater brackish water freshwater temperature [ C] 39 / 50

40 Density Benchmark Clemens Cremer Physical sand tank experiment Simmons et al. (2002, Transp Porous Media) Numerical simulation (HydroGeoSphere) Identical fingering 40 / 50

41 Outline Work Area Mathematical Methods Research Group Student Projects My Ongoing Projects Outlook 41 / 50

42 Gas Mining 42 / 50

$fracturing) fracking Injection of frack fluid to crack the rock Gas can then escape to the surface Environmental concern (frack fluid)$

43 Gas Mining Extraction of natural gas Recoverable gas ~ 1500 km 3 Could supply the entire US for 2 years Extraction via (hydraulic fracturing) fracking Injection of frack fluid to crack the rock Gas can then escape to the surface Environmental concern (frack fluid) 43 / 50

44 Gas Mining Lake Ontario (1640 km 3 ) 44 / 50

45 Gas Mining Hydraulic fracturing frack fluid? 45 / 50

46 Frack Fluid Frack fluid contains toxic additives Arsenic Alcohols Benzene Can these chemicals contaminate groundwater? 46 / 50

47 Gas Mining HydroGeoSphere model Preliminary results 0.25 h 1h 4h 7h 47 / 50

48 Outline Work Area Mathematical Methods Research Group Student Projects My Ongoing Projects Outlook 48 / 50

49 Outlook Open to unresolved questions CO2 sequestration Seawater intrusion Estimation of geothermal potential 49 / 50

50 Thank You Please visit us at: 50 / 50

INL Capabilities and Approach to CO 2 Sequestration. 4 th U.S.-China CO2 Emissions Control Science & Technology Symposium

www.inl.gov INL Capabilities and Approach to CO 2 Sequestration 4 th U.S.-China CO2 Emissions Control Science & Technology Symposium Travis McLing, Ph.D. Energy Resources Recovery and Sustainability September