Geological Storage Group

Transcription

1 Geological Storage Group Michael A. Celia and Jan M. Nordbotten Jean H. Prevost and George W. Scherer Catherine Peters Also: Mark Dobossy (Princeton Univ.) Sarah Gasda (Univ. North Carolina) Stefan Bachu (Alberta EUB) Helge K. Dahle (Univ. of Bergen) Benjamin Court (Princeton Univ.) Adam Janzen (Princeton Univ.) Juan Nogues (Princeton Univ.) Ed Matteo (Princeton Univ.) Zhihua Wang (Princeton Univ) Lee Y. Chin (ConocoPhillips)

2 Outline Overview of Activities Measurements over different length scales Modeling over different length and time scales Modeling efforts jointly between Princeton and Bergen Specific Focus Areas 1) Measurements: Cement and rock structure at very small scales, with issues of upscaling. 2) Modeling: Geochemistry, Nonisothermal effects, Large-scale numerical, analytical, and hybrid models 3) Our Hierarchical Modeling Concept Next Steps and Ongoing Work

3 Small-scale Measurements Structure of cement Scanning electron micrograph of heavily corroded iron-free cement after supercritical drying shows the high porosity resulting from the reaction. In this case, the drying fluid was CO 2, so the sample is heavily carbonated.

4 Small-scale Measurements Reactive mineral availability and heterogeneity in Alberta Basin sandstone BSE SEM image of a sandstone from the Viking formation EDX Elemental Maps Processed BSE Image Combined BSE-EDX mineral map Elements of a BSE-EDX mineral map. Reactivity in sandstones is notoriously difficult to characterize due to the high degree of consolidation and cementation. This novel image processing algorithm allows us to quantify the accessibility of minerals to carbonic acids, thereby determining mineral reactivity under acidic conditions.

5 Kinetics of Corrosion Experimental rates of attack (A. Duguid) Correctly simulated by model (B. Huet) using estimated diffusivity value recently verified by NMR

6 Properties of Corroded Cement For accurate modeling, need to measure transport properties and strength Diffusion coefficient measured using NMR - value within a factor of 2 of Huet s fitted value Strength of corroded cement to be measured by micro-indentation Permeability of shale measured by beam-bending - highly anisotropic, nanodarcy permeability

7 Indentation to Measure Strength To find the change in mechanical properties of the corroded cement, use a diamond indenter depth of indentation & size of cracks indicates strength instrument now ready for use Translation stage Stepper motor Load cell Diamond point

8 Diffusivity ( m 2 /s ) Diffusion in Corroded Cement NMR can be used to measure the rate of diffusion of water in a porous material Cement severely corroded by HCl: D = 8 x m 2 /s 10 8 As diffusion delay time increases, molecule moves 6 4 D H2O 8 x m 2 / s farther through 2 labyrinth of pores Diffusion Delay (ms)

9 W ( t ) / W ( 0 ) Permeability of Shale Permeability found by bending saturated plate and measuring time for relaxation of pore pressure NanoDarcy-range permeability measured in shale Relaxation of force, W, on beam results from hydrodynamic & viscoelastic processes Perpendicular to bedding, permeability is ~10-22 m 2 (0.1 nanodarcy) 0.85 Measured Fit Hydrodynamic Viscoelastic t ( s )

10 Penetration of CO2 into Shale Samples of cement retrieved from wells in natural CO2 deposits show some carbonation Carbonation previously attributed to leakage along well Simple analytical model shows that shale caprock becomes saturated with CO2 over millions of years After well placed, cement reacts with CO2 diffusing from surrounding shale For typical diffusivity in shale (~10-11 m 2 /s), we predict mm to cm of carbonation by this mechanism Carbonation is not necessarily indicative of leaks around the well

11 Borehole-scale Measurements

12 Modeling: Philosophy Focus on leakage mechanisms and leakage estimation. Diffuse leakage through caprock formations Concentrated leakage along faults Concentrated leakage along wells Represent details where necessary Highly resolved processes and computations along concentrated leakage pathways. Hierarchical simplification of models at larger scales, taking advantage of system physics. Blend models into practical tools Hybrid numerical-analytical models Vision of seamless hierarchical modeling platforms.

13 Local Modeling around Wells: Dynaflow Fully Coupled Simulator Geomechanics Multi-Phase flow Heat flow (including heat of reaction) Flash via equation of state Modular flash and geochemistry Transportable to other codes (e.g., Eclipse) Related models: TOUGH2 (K. Pruess, LBL): similar flash capabilities but not modular; no coupled poromechanics; no cement geochemistry NUFT (Nitao, Wolery, J. Johnson, LLNL): no extensive thermodynamic data base for cement geochemistry; no coupled poromechanics FLOTRAN (Lichtner, J. Carey, LANL): reactive transport; no coupled poromechanics ECLIPSE (Schlumberger), VIP (Halliburton),.: no accurate CO 2 flash; no cement geochemistry; no coupled poromechanics

14 Cement Geochemistry Added geochemistry to the reactive transport module in Dynaflow Accounts for all phases in cement paste reaction with carbonic acid (or dry CO 2 ) precipitation and re-dissolution of calcium carbonate change in porosity Modular structure transposable to other codes

15 CO 2 flow through damaged casing Damage channel Z= 0 m P0=0.1 MPa T0=5 dgc gravity R0 = 1m R1=10 m R2 = 50 m Permeability: K_damaged = 10 darcy K_intact = 1 darcy Liquid CO2, over pressure = 0.5 MPa Z=-600 m P0=5.26 MPa T0=15 dgc Rock: Thermal cond.: 2 W / m K Specific heat: 1000 J / kg K Density: 2600 kg /m 3

16 50 m 600 m Time = 5 days T_max = 15 dgc T_min = 0.8 dgc

17 50 m 600 m T_max = 15 dgc Time = 10 days T_min = -1. dgc

18 50 m 600 m Time = 17 days T_max = 15. dgc T_min = -3. dgc

19 Hierarchical Approach to Large-scale Modeling 1. Macroscopic sharp interface 2. Vertical equilibrium 3. Separation of time scales 4. Locally constant fluid properties/isothermal 5. Dominant spatial features (Large scale layering and concentrated leakage pathways) 6. Parameter uncertainty is dominant 7. Horizontal and homogeneous formations See: Celia, M.A. and J.M. Nordbotten, "Practical Modeling Approaches for Geological Storage of Carbon Dioxide", under review, Ground Water, 2009.

20 Plume-Scale Modeling

21 Overview of Large-scale Leakage Model (ELSA) Domain size: 50 km x 50 km 1,228 Wells Complex stratigraphy (up to 27 layers) Solutions using our semi-analytical model. Formation properties assigned deterministically. Effective permeability of wells assigned stochastically. >10,000 simulations.

22

23 Layer Properties Aquifer Name Depth [m] Thickness [m] Permeability [md] # Wells Max Inj Rate [Mt/year] Wells reached by CO 2 plume Belly River Cardium Viking Mannville Nordegg/Banff Wabamun Nisku Keg River Pika Basal Sandstone

24 Injection Scenario One vertical injection well Injects into only one formation Injection at center of domain Injection rate constant and constrained by fracture pressure All formation properties assigned deterministically Well properties are assigned stochastically Calculate leakage of CO 2 and Brine

25 Effective Well Permeability Fully Random: Bi-modal lognormal distribution Vertical correlation structure Soft Data and Well Scoring System: Watson and Bachu (2008) well scores Conditional probability distribution Direct Measurements: Approach of Gasda et al. (2008) and Crow et al. (2008) Needs to be integrated into modeling framework

26 Soft Data and Well Scores Deep Leakage Potential (DLP) Score range Mean well segment permeability Low < to Medium 2 to to High 6 to to Extreme > to Scores from Watson and Bachu (2008)

27 Model Results

28 Recent developments High performance implementation Complete re-implementation of code in C++ Highly object oriented, and modular Runs on BlueGene; realizations take about 10 min. per processor More physics included Diffuse Caprock leakage fully implemented Improved implementation of similarity solutions for low leakage rates User friendly interfaces Standard input is TCL scripted files Simple web-based interface (monty.princeton.edu/~mark/injsim2/) Matlab as front-end under implementation Separate numerical vertically-averaged code Application including soft data on well quality 10s of thousands of runs conducted investigating the Alberta area

29 Code comparison (ELSA and VESA)

30 Large scale injection Eclipse VESA

31 Collaboration with U. Bergen Newly initiated graduate and post-graduate exchange program. Streamline methods for fractured reservoirs. Streamline-normalline based numerical methods for vertically integrated formulations. Fast solvers for simplified physics on complex geometries (together with SINTEF Oslo). Large scale full physics simulations of North Sea reservoirs. Analysis of model equations for CO 2 transport in aquifers, alternatives to the Advection-Dispersion class of models. Numerical studies of fundamental processes affecting CO 2 dissolution rates, including capillary fringe and interface dynamics. Joint development of benchmark studies. CO 2 modeling workshop at Svalbard, August

32 Ongoing and Future Work Development of a Hierarchical modeling Platform: Include a range of models covering different levels of complexity. Allow for user-controlled mixtures of different models within different subdomains. Provide seamless integration to a variety of user interfaces. Development of multi-scale models capable of much larger simulations. Computational and practical aspects of different injection strategies (multiple injection points) Simulations to support regulatory frameworks Continue with field testing and applications Develop stronger links to DOE Regional partnerships Continue to work with national and international partners on workshops, code comparisons, and related activities. Develop a broader international consortium of universities focused on research and education in CCS.