Geological Storage Group

Transcription

1 Geological Storage Group Also: Michael A. Celia Jean H. Prevost George W. Scherer Jan Nordbotten (U. Bergen and Princeton U.) Sarah Gasda (Univ. North Carolina) Bruno Huet (Schlumberger) Stefan Bachu (Alberta EUB) Mark Dobossy (Princeton Univ.) Benjamin Court (Princeton Univ.) Ed Matteo (Princeton Univ.) Zhihua Wang (Princeton Univ) Lee Y. Chin (ConocoPhillips)

2 Problem Overview Outline Length and Time Scales Where we are focusing our efforts Some of our Recent Results 1) Small Scale: Cement Geochemistry, Nonisothermal effects, Geomechanics 2) Intermediate Scale: Risk versus Depth of Injection 3) Field Experiments: Collaboration with BP/Schlumberger/CCP Next Steps and Ongoing Work

3 Time Scales Two-phase Flow Early and Intermediate times (1 to 100 yrs) Gravity override and viscous instabilities Residual CO 2 saturations after injection ceases Dissolution Intermediate to late time (100 to yrs) Gravity instabilities (miscible transport) Mineral Trapping Late time (500 to >5000 yrs) Geochemical reactions (From IPCC, 2005)

4 Length Scales and Leakage Length Scales: Basin scale ( km 2 ) CO 2 plume scale ( km 2 ) Scale of pressure perturbations / boundary conditions Scale of important flow and leakage features (10-2 m 2 ) Leakage: Diffuse leakage through cap rock Leakage along natural features: fractures and faults Leakage through human-made pathways: Wells

5 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

6 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

7 Kinetics of Corrosion Experimental rates of attack (A. Duguid) correctly predicted by model (B. Huet)

8 Kinetics of Corrosion Without leak, time to dissolve: 2 m of cement ~100 yrs 6 m of cement ~1000 yrs Therefore, leakage is unlikely without some pre-existing annulus or crack

9 Modeling Leakage along Wells If a gap exists, the escaping fluid will react with the cement, but it will also boil only our flash can describe this process Simulation shows advance of boiling front (gas, aqueous phase and CO 2 - rich liquid Other flash models are unable to handle this case

10 Geomechanics and Well Leakage Pressure created by injection of CO 2 deforms overburden Simulation investigates stresses from bending of cap rock (found to be negligible) and shear of cement relative to cap rock (causing sliding, but not leakage)

11 Geomechanics and Well Leakage Pressure created by injection of CO 2 deforms overburden Simulation investigates stresses from bending of cap rock (found to be negligible) and shear of cement relative to cap rock (causing sliding, but not leakage)

12 Plume-Scale Modeling

13 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.

14 Leakage Risk versus Depth of Injection Thickness [m] Injection Rate [Mt/yr] Cumulative number of abandoned wells Total

15 Model Results (1) Cdf of top layer leakage in scenario 1:4 [largely intact] after 40 years (Uncorrelated permeabilities)

16 Model Results (2) Cdf of top layer leakage in scenario 4:1 [largely degraded] after 40 years (Uncorrelated permeabilities)

17 Model Results (3) Cdf of mass accumulated in top layer after 50 years [largely degraded] uncorrelated [Largely intact] uncorrelated [mixed] uncorrelated [largely degraded] Fully correlated

18 Field Measurements First Experiments performed Summer 2007 Part of CCP2 (BP and Schlumberger project) Results indicate good cement in the tested region Additional test(s) planned Disturbed zone, k w From: Gasda et al., Env. Geol., Photo From: Walter Crow, BP.

19 Ongoing Work Coupling of models across scales: Incorporation of geochemistry and nonisothermal effects (Dynaflow) into analytical models (Elsa). Incorporation of more complex flow and mechanics along leaky wells. Development of hybrid numerical-analytical models. Use of hybrid numerical-analytical models at basin scale. Injection strategies (injectivity constraints) Simulations to support possible regulatory frameworks Field applications: More (many more) tests for effective well permeability Broader Industry Partnerships Research integration into commercial ventures (At scale we need to "Learn by Doing").