IEA GHG Weyburn-Midale CO 2 Storage and Monitoring Project *Risk Assessment*

Transcription

1 IEA GHG Weyburn-Midale CO 2 Storage and Monitoring Project *Risk Assessment* Rick Chalaturnyk Geological Storage Research Group Department of Civil and Environmental Engineering University of Alberta 3 rd Risk Assessment Network Meeting 15 th 16 th August, 2007 Imperial College, London, UK

2 True Quantitative Risk Assessment!

3 Outline of Presentation Phase I Project Summary Geoscience Characterization Geophysics Geochemistry Reservoir Simulation Risk (Performance) Assessment Final Phase Technical Research Program Research Themes Summary

4 Phase I Project Overview Launched in July 2000 by PTRC in collaboration with EnCana Assess technical and economic feasibility of CO2 geological storage The CO2 is pipelined from Dakota Gasification Co. plant in Beulah, N. Dakota, USA and injected into the Weyburn oil field at an initial average rate of 5000 tons/day, for a total of approx. 20 million tones over the 20-year life of the project Funded by 15 industry and government sponsors (Canada, USA, Japan, European Union) Employed 22 technology organizations and some eighty specialists in six countries

5 Final Phase of IEA GHG Weyburn-Midale CO 2 Storage and Monitoring Project Non-Technical Component REGULATORY Clear, Workable and Science-based Regulations for CO 2 Geologic Storage PUBLIC COMMUNICATIONS Public Awareness Driven by the need for better public awareness of CO2 geological storage, especially on the issue of safety. FISCAL POLICY Technical Components GEOLOGICAL INTEGRITY WELLBORE INTEGRITY STORAGE MONITORING METHODS (Geophysics & Geochemistry) RISK ASSESSMENT; Storage and Trapping Mechanisms; Remediation Measures; Environment, Health and Safety

6 Final Phase Technical Work Program Program Principles Theme 1: Geological Integrity THEME 2: Wellbore Integrity THEME 3: Storage Monitoring Methods (Geophysics & Geochemistry) THEME 4: Risk Assessment; Storage and Trapping Mechanisms; Remediation Measures; Environment, Health and Safety THEME 5: Shared-Data Environment (SHADE)

7 Principles for Design of Final Phase TWP Integrated Focus on Phase 1A Area C Midale Field to serve as further validation of a storage and monitoring practice B A B Phase 1A data: Reprocessing and extended analysis of seismic data; Re-analyze geochemical data/mapping; Technical Research Tasks Re-scope Required for Policy No Yes Data validation, peer review of Phase 1 information; and Integration of all Phase 1 data onto common platform for efficient sharing among research providers (RPs). Common Software Platforms Re-scope Re-scope Critical to Performance Assessment No Required for Best Practices Manual No Yes Yes Approve Not Approved

8 Final Phase of IEA GHG Weyburn-Midale CO 2 Storage and Monitoring Project Well Model Well Integrity Geological Model Fault Characteriztion FINAL PHASE Wellbore Integrity Database Down-hole Testing Down-hole Sampling & Lab Testing Lab Testing of Casing and Cements Geochemical Modelling Existing Practices & Materials Natural Analogues for Cement Interval Modeling Fracture Network Characterization Mineral Trapping Monitoring Tools Reservoir Simulation Reactive Transport Aquitard Properties 3D-3C seismic aquisition Passive Seismic Monitoring Time-lapse well-logging Downhole spinner survey Well pressure measurements Dedicated seismic monitoring system ERT Fault Activiation Mississippian Hydrogeology Quantifying fluid flow above Watrous Direct Measurement Validate Stratigraphy Model Development Natural Analog Expert Panel Bow-Tie FEP s Consequence Analysis Risk Profile Assessment (Qualitative) Performance Assessment Performance Assessment (Model) Regulatory and Public Communication CO2 Composition Leak Detection Corrosion Recycle Decommissioning Policy Business Operational Issues Operational Issues Best Best Practices Manual Manual Data reprocessing Seismic modelling and inversion Seismic-constrained reservoir simulation Distribution & Distribution and Fate of CO Fate of CO2 2

9 Theme 1 Geological Integrity Knowledge Gap Drivers FINAL PHASE Reservoir characterization protocols and selection protocols are missing. Geomechanics of the geological barriers that provide storage integrity to the containers are incompletely understood. Integration of results for all relevant CO 2 geological storage projects has not yet taken place Research is currently tending to drive the environmental and industrial agenda instead of the reverse. Need comprehensible technical summaries to be used in drafting generic and specific regulations.

10 Geoscience Characterization Objectives: Assess integrity of geological container for storage of CO 2 Provide input for performance and risk assessment and also scenario analysis of the long-term fate of CO 2 in the subsurface (Geological Model)

11 Weyburn Field: Phase 1A EOR Area 11 mi Existing EOR Area 14 mi Future EOR Area n Discovery: 1954 n ECA WI: 62.1% n OOIP: 1,400 MMbbls n Formation: Miss. Midale n Depth: 1460 m n Area: 45,000 acres n Active Prod: 648 total, 278 hz. n Sour crude: API n Cum. Prod.: 398 MMbbl (28%) n YTD Avg.: 29,800 bbls/d n EOR patterns in place: 44 typical pattern

12 Reservoir Structure

13 Weyburn CO2 Storage System W Surface lineaments Surface lineaments 10km 10km Performance Assessment Area Performance Assessment Area (System Domain) (System Domain) EOR EOR S N N ife rs Pot able aqqu uife rs Potable a E wells wells 1.5km 1.5km Reg Regiiona l h yd ona l r h ydrogeo log ogeo ica l f log ic lo w a l f lo w Horizon of CO2 Injection Horizon of CO2 Injection Midale Evaporite Midale E vaporite Midale Beds N re Bios phe Bios phere A quitard Bear paw A quitard Bearpaw er iv R lly Be er Belly Riv rd ita u q A o Colorad A quitard Colorado as tlequitard New c u A Joli Fo rd c as tle Mannv illneewfou A quita Joli A quitard ard annv ille V angum ic ss A quitard ra Ju V anguard rd uita us A qss ic Watro Juraian p ip s is uitard Mis s us A q Watro ia p n is s ip Mis s Midale Beds Sub-Mesozoic Unconformity Midale Beds subcrop Midale Beds pinchout Sub-Mesozoic UnconformityMidale Beds subcrop Midale Beds pinchout

14 Seismic and Aeromagnetic Integration

15 Property Characterization

16 Geological Model Areal extent 10 km beyond CO 2 flood limits Geological architecture of system Properties of system lithology hydrogeological characteristics faults Can be tailored for different RA methods and scenario analyses

17 Geological Container at Weyburn Suitable for long-term storage of CO 2 Effective trapping setting Primary seals are highly competent Thick shale units above the reservoir serve as significant barriers to vertical flow (secondary seals) Basin Hydrogeology hydraulic separation between Paleozoic and Mesozoic aquifers sluggish flow in Midale Beds Tectonic elements have influenced all levels of stratigraphy (deposition, erosion, dissolution) No hydraulic evidence of fluid movement

18 Suggested Theme 1 TWP Tasks/Ranking FINAL PHASE Identify the minimum data set required for successful site selection (H*) Firm protocol for selection of suitable sites for CO 2 geological storage, using Weyburn learning's to develop more universal guidelines (H) Quantify the integrity of faulted/fractured seals in the Weyburn area. (H) Summarize the predicted impact of CO 2 and CO 2 -rich fluids on geochemical and geomechanical processes on regional reservoirs and seals. (M*) Describe conditions that would lead to high and low risk environments for seals, and for high and poor performance CO2 traps. (M*) Compile a summary of predicted impacts, probability of occurrence and time scales for these processes at Weyburn field and similar sites in the Williston Basin (M*) Produce a summary report contrasting Weyburn site parameters to other studied areas, e.g. Permian Basin of West Texas, Sleipner, CO2CRC ESSCI s, In Salah in Algeria. (M)

19 Theme 1 Final Phase Activities FINAL PHASE o o o o o o Investigation of natural discontinuities (faults, fractures, lineaments) Fracture/fault reactivation and flow characteristics Investigate potential of geochemical reactions effectively widening fractures using geochemical modeling involving fracture fluid flow and kinetic reaction rates. Hydrogeological and petrophysical characteristic Examine natural analog for Weyburn/Midale site situated in western portion of Williston Basin Model Development

20 Theme 2 Well Integrity Knowledge Gap Drivers FINAL PHASE To develop methods for assessing long-term wellbore integrity and the application of remedial methods, including wellbore monitoring technology; Degradation characteristics of materials used to abandon wellbores Essential parameters to define wellbore integrity; Current well abandonment practices & long-term CO2 storage and proposed future abandonment/remediation requirements; Conduct downhole testing (pressures and mobile fluids that signal CO2 migration out of zone); and Document safe practices and impact on wellbore integrity and geomechanics.

21 Suggested Theme 2 TWP Tasks/Ranking FINAL PHASE Wellbore Database Data Compilation Extended to cover Region A and additional parameters should be added to the database (e.g., work-over frequency, casing vent gas or sustained casing pressures) Synthesis of Existing Practices and Materials Used in Operations Relevant to EOR-based CO2 Geological Storage Down-hole Sampling of Cements Exposed to CO2 Laboratory Testing of Selected Casing and Cement Materials Simulation of Wellbore Systems Evaluation of Casing-Cement-Formation Integrity by Down-hole Testing Geochemical Modeling (LLNL) Performance Assessment Modelling of Wellbores

22 Theme 3 Storage Monitoring Methods Geophysics FINAL PHASE OBJECTIVES Monitor the changes in subsurface distribution and concentration of injected CO2; Monitor levels of microseismicity induced by CO2 injection; Assess the economy, accuracy and applicability of monitoring methods for determining CO2 volumes, distribution, concentration and leakage from the reservoir; and Determine the monitoring technologies needed as a function of time and estimated risk level

23 Theme 3 Geophysics Storage Monitoring FINAL PHASE 3D-3C time-lapse seismic data acquisition Passive seismic monitoring Time-lapse well-logging Downhole spinner surveys Well pressure measurements Dedicated Seismic Monitoring System demonstrate improved data repeatability afforded by a semi-permanent installation and allow acquisition of additional intermediate time-lapse surveys. This is intended as a demonstration project and would involve deployment of a 2D or sparse 3D array Electrical Resistance Tomography Dedicated Monitoring Well

24 Geophysical Monitoring Theme Phase 1 OBJECTIVES Test and develop methods for monitoring CO2 injection. Phase 1 Enhance conformance control through improved reservoir characterization and prediction. Verify volumes of CO2 in the subsurface. Establish safety and containment of injected CO2.

25 Monitor 1 and 2 Difference Maps

26 CO2 distributions from Seismic and Simulator, 1st iteration (Monitor 2 Survey)

27 CSM RCP Project Observations Gaps were recognized upon the completion of Weyburn Additional research to clarify and advance the understanding of seismic monitoring: Accurately monitor and produce quantitative results to define volumetrics. Full integration with reservoir simulation. Providing scientific evidence to verify geomechanical changes in the reservoir.

28 Caprock Containment Measurements by Seismic

29 Geophysical Monitoring Summary Monitoring methods clearly show physical and chemical effects associated with CO2 injection. Seismic methods show robust time and amplitude anomalies. P-wave amplitudes are highly sensitive to CO2-rich gas phase at low levels of saturation (5-10%); good for detection, but makes volume estimation from seismic alone difficult. Volumetric analysis of seismic anomalies suggests associated mean CO2 saturation of ~20%, similar to reservoir simulator results. Fractional velocity changes of up to 12%: mainly Sg with secondary P effects (2-3%). Off-trend anomalies identify areas where channelling of CO2 is occurring. Heightened sensitivity of the amplitude response to changes in the upper reservoir (Marly unit) allows partial discrimination of vertical CO2 distribution using amplitude and time delay anomaly maps.

30 Geophysical Monitoring Summary (cont d) 1.4 million m3 (2500 tonnes) or 4 million m3 (7500 tonnes) are minimum detectable amounts of CO2 using the time-lapse P-wave amplitude differences or travel time delays, respectively. These estimates may be overly conservative by a factor of eight. No evidence for CO2 escaping from the reservoir. Based solely on the seismic results, it is estimated that the maximum amount of CO2 that may have migrated above the reservoir is <2% of the total injected volume. Contribute to more accurate reservoir flow simulations. Microseismicity is low level. 60 microseismic events with magnitudes of 3 to 1 recorded during 6-months. Events associated with changes in production or injection (e.g., water-to-gas) where local pressure transients might be expected. Magnitudes and occurrence frequency of microseismicity are equal to or less than for water flooding that has been ongoing for more than 30 years.

31 Theme 3 Geophysics Data Processing, Analysis, Inversion and Modelling Data Reprocessing improve on the current time-lapse images, to better quantify the data repeatability, and to extract more information from the existing seismic data. Given the amount of effort that was focused on obtaining robust time-lapse images from the P- wave data, the focus of reprocessing efforts should be on the converted-wave and pure shear components. A key goal is improved pressure vs. saturation discrimination Seismic Modelling and Inversion address the primary goals of pressure-saturation discrimination, fracture characterization and improved depth resolution Passive Seismic data acquired will be used for geomechanics and fracture characterization

32 Theme 3 Storage Monitoring Methods Geochemistry Monitor the compositional evolution of reservoir fluid phases (aqueous, hydrocarbon) catalyzed by CO 2 injection using both well-head and in situ sampling techniques. Monitor for the direct or inferred presence of exogenous CO 2 within reservoir overburden. Predict the reservoir/cap-rock compositional/permeability evolution using reactive transport modeling capabilities. Carry out lab-scale experimental/model development studies that directly support monitoring and simulation activities. Provide an overview of geochemical monitoring/modeling techniques & the criteria/methodology for selecting appropriate site-specific suites (for inclusion in the BPM)

33 Geochemical Monitoring Program Phase 1 Program Monitoring Detailed field fluid sampling program, for approximately 50 wells, started before CO2 injection and STILL CONTINUING. Experiments & Data Verification Autoclave and core flood experiments CO2-reservoir mineralogy-fluid reactions. Geochemical analysis and modeling of the experiments. Detailed mineralogical analysis of the Weyburn Midale reservoir and the adjacent geosphere. Prediction Modeling of the geochemical reactions in the reservoir over a 5,000 year period. Modeling of potential reactions in the adjacent geosphere. Analytical Major and trace dissolved constituents, including organic acids. Oxygen, carbon, hydrogen and sulpur isotopes in the water and gas. Produced gas composition. Sampling: generally 50+ wells each trip Baseline (before CO2 injection (Sept 2000) 3 sampling trips per year High frequency sampling on selected wells.

34 Changes in Resistivity Phase 1 Program

35 Phase 1 Program Ca, alkalinity and δ13c-hco3 (289 days)

36 Phase 1 Program Ca, alkalinity and δ13c-hco3 (930 days)

37 Reservoir Simulation Program OBJECTIVES To establish reliable prediction tools and methodology for CO2 storage performance To predict CO2 movement/distribution and storage performance in the Weyburn reservoir To investigate alternative CO2 storage cases after EOR with a focus on promoting additional CO2 storage

38 Reservoir Simulation Methodology Degree of Detail Fine Coarse ARC Three Two Preliminary Improved Single-Pattern Simulations Upscaling ARC Three Coarse-Grid Single-Pattern Simulations EnCana Original 9-Pattern Simulation Upscaling Upscaling Upscaling ARC 75-Pattern Simulation EnCana STRATA Geological Model Weyburn Field No. of Pattern

39 75 Pattern Simulation EOR Base Case Follow EnCana s EOR operating strategies as closely as possible Roll out plan: Injection plan: inject 50 60% HCPV CO 2 Maximum CO 2 supply: m 3 /d (95 MMscf/d) Maintain pressure of reservoir > 18 MPa for miscibility Depletion plan: water flush of depleted patterns to liberate some of the CO 2 for recycle Recycle plan: approximately 60% of total CO 2 injection Oil/Water Production Rate (m 3 /d) Oil (EOR + Buffers) Water (EOR + Buffers) Field Data (Oil) Field Data (Water) EOR Base Case OOIP in 75 EOR Patterns = x 10 8 m 3 1/1/ /27/ /22/ /17/ /12/2034 Time Date Start CO 2 -EOR Oil Recovery in EOR Patterns 26% OOIP (30% OOIP) 47.2% OOIP (46% OOIP)

40 Theme 3 Geochemistry Storage Monitoring FINAL PHASE Well-head fluid sampling (Weyburn Phase 1A) In situ fluid sampling Issues with degassing Hydrocarbon sampling Multiple-contact miscibility processes Monitor potential supra-reservoir CO 2 leakage Shallow groundwater monitoring Soil gas monitoring Noble gas isotopes

41 Theme 3 Geochemistry Storage Prediction FINAL PHASE Reactive transport modeling Predict EOR production & intra-reservoir CO 2 storage mechanisms dual-permeability models - predict CO 2 migration paths, EOR production, CO 2 partitioning between recycled and sequestered fractions, sequestration partitioning among hydrodynamic, hydrocarbon solubility, aqueous solubility, and distinct mineral trapping mechanisms, and reservoir/cap-rock permeability evolution during active- and post-injection regimes. Predict long-term intra-reservoir isolation performance Identify and model all potential cap-rock leakage sites and mechanisms (e.g., micro-fractures, faults, local wellbore environment); results feed into Theme 4 (and potentially Theme2)

42 CO 2 -EOR and CO 2 Storage CO 2 Inventory (tonne) 30,000,000 25,000,000 20,000,000 15,000,000 10,000,000 In Gas In Oil In Water EOR Base Case Total CO 2 Stored = MT 30.5% 44.2% 5,000, % 0 Jan-00 Jan-02 Jan-04 Jan-06 Jan-08 Jan-10 Jan-12 Jan-14 Jan-16 Jan-18 Jan-20 Jan-22 Jan-24 Jan-26 Jan-28 Jan-30 Jan-32 Jan-34 CO 2 Distribution EOR Base Case / 01 / CO 2 Global Mol. Fr. End of EOR Vertical/Horizontal Scale = 30/1

43 Theme 3 Geochemistry Process/property studies FINAL PHASE Fracture permeability and two-phase flow measure fracture permeability in reservoir cores as a function of confining stress and CO2 saturation; to correlate fracture surface roughness and stress-dependent relative permeability; and to measure two-phase flow rates in casts of reservoir fractures as a function of aperture, roughness, and fluid density/viscosity Fracture permeability alteration and process scaling integrated experimental/computational study to measure and predict CO 2 - induced fracture permeability evolution within the Midale reservoir CO2-fluid-rock interactions conduct and model a series of Weyburn-relevant CO 2 -brine-rock interaction experiments to assess the potential short- and long-term impact of mineral trapping on storage performance Pore-scale mineral alteration apply advanced micro-beam techniques to quantify micron-scale 3-D pore space geometry as well as the distribution and composition of both pore-lining and matrix mineralogy in pre- and post-co 2 flood cores

44 THEME 4: Risk Assessment; Storage & Trapping Mechanisms; Remediation Measures; HSE FINAL PHASE Knowledge Gap Drivers: A need to find consensus on risk/performance methodologies suitable for site approval for operations and for earning (storage) credits; A need for appropriate risk assessment methods and risk mitigation measures for confirming the safety and reliability of geological storage of CO 2 ; A strong need to rationalize the selection of cost and time-effective methodologies for risk assessment of the long-term fate of stored CO 2 ; and A recognition that risk/performance assessment is critical for the development of future regulations and/or identifying and addressing gaps that may exits in existing regulatory frameworks

45 Risk Assessment Program Phase 1 OBJECTIVES Apply risk assessment techniques to predict the long-term fate of CO2 within the storage system Identify risks associated with geologic storage Assess ability of oil reservoirs to securely store CO2 (where CO2 migrates to and what are the fluxes) Derive how much CO2 is stored in the Weyburn reservoir as a function of time Explore consequences (HSE) of any leakage Provide assessment results primarily in terms of flux of CO2 from the geosphere as function of time

46 Assessment Methodology Phase 1 FEP s (Features, Events and Processes) Systems Analysis Scenario Development Base Scenario Alternative Scenario s Deterministic Risk Assessment Probabilistic Risk Assessment

47 Features, Events and Processes Dissolution of Minerals Mineral Surface Processes Several RP workshops were Porewater held to Chemistry develop FEP s Integration with EU and CCP efforts in FEP s Mineralogy of Reservoir Rock So many FEP s were developed that everyone was pretty much FEP in FEP d out with FEP s. Identification of Task Providing Input Data Change Hydrogeological Properties as Mineralogy Changes

48 Base Scenario and System Model Phase 1 Base Scenario: expected evolution Include FEPs relevant to long-term CO2 migration Caprock intact and no geological structure failure, but consider natural or man-made (near wellbores) fractures, if any exist All wells are abandoned at the end of EOR, and sealed according to current practice procedures System Model for assessment 75 patterns plus 10-km surrounding Midale formations Aquifers and aquitards above and below Midale reservoir All wells within the model domain are considered Time scale: 5000 yrs or 50% loss of CO2 Biosphere: start from the deepest possible potable aquifer

49 Alternative Scenarios Engineering options for EOR Reservoir operation options Well abandonment options Impact of salt dissolution Fault activation/re-activation Tectonic activity Human intrusion

50 Geomechanical Performance Assessments Mechanical Earth Model Fractures in the Caprock Phase 1 Influence of Historical Injection / Production in Weyburn Field Impact of Elevated CO2 Injection Pressures Influence of Salt Dissolution Processes Hydro-Geomechanical Properties of Bounding Seals

51 Phase 1 In Situ Stresses

52 Phase 1 Mechanical Earth Modeling and Salt Dissolution

53 Stress Changes due to Salt Dissolution

54 Stress Changes due to Salt Dissolution

55 Stress Changes due to Salt Dissolution

56 Stress Changes due to Salt Dissolution

57 Well Characteristics Phase 1 UWI Well TVD Borehole 26 (m) Diameter (mm) )NO INFO ( No Info Class 7 Type 0 No. o f W e lls Age w Size (m) 0 Hole TVD (m) Spud Date: UWI W Period: Spud Date: <1300 Type: HTAL < 1300 Period: Horizontal Scale: 15 Purpose 156 OIL WELL (PUMPING) SCHEMATIC FOR CO Type: VCAL Horizontal Scale: 15 Purpose WAG INJECTOR Surface Casing Casing Size (mm) Surface Hole 0.00 Casing Grade Surface Casing Surface Information Surface Hole 60 Surface Cementing Surface Cementing 80 Surface Information Casing 50 Surface Kick-Off Casing Size Grade Length JTS Thickness Hole Surface size Hole TVD Hole TMD 60 Set TMD Kick-Off Depth (mm) (m) (mm) (mm) (m) (m) (m) (m) Size Grade Length JTS Thickness No. of Wells Hole size Hole TVD Hole TMD Set TMD No. of Depth Wells H (mm) (m) 18 1 (mm) (mm) (m) (m) 40 (m) (m) H N.A. Cementing Intermediate 1 20 Cementing )blank( Description Fluid Type Cement Vol. Slurry Vol Hole No Info 10 Intermediate size Hole TVD Hole TMD Set TMD (tonnes) (m3) 3 (mm) (m) (m) (m) Description Fluid Type Cement Vol. Slurry Vol Cementing(Lead) 6 0 J-379 Hole size Hole TVD Hole TMD Set TMD LEAD Intermediate Hole (tonnes) (m3) J-379 (mm) (m) (m) (m) 2 LEAD 5.00 J Production Casing J-55 Intermediate Information Intermediate Hole K-55 Size (mm) Production Casing Intermediate Information K-55 6 Casing Grade )NO INFO( Casing Size Grade Length JTS Thickness No Info (mm) (m) (mm) Size Grade Length JTS Thickness J (mm) (m) (mm) J Cementing MIDALE MIDALE EVAP. EVAP (1411.2) Cementing Casing Length Vertical (m) } (1399) Description Fluid Type Cement Vol. Slurry Vol (tonnes) (m3) Description Fluid Type Cement Vol. Slurry Vol. Cementing(Tail) MIDALE (1401.5) LEAD (tonnes) (m3) MIDALE (1420.4) TAILEAD Kick-Off point Cementing(Lead) CAPROCK CAPROCK No. of Wells Casing Length (m) 0 <1300 < 1300 No. of Wells SCHEMATIC FOR OIL CO SCHEMATIC FOR WAG 2 PRODUCTION WELL INJECTION WELL No. of Wells No. of Wells No. of Wells No. of Wells 0 Type Wellhead Cement Fluid Annulus Cement 1 Fluid 2 Volume m 3 Type Volume m 3 Production Casing 1 Vertical Class G Vertical RFC 6.0 lightweight Horizontal Class G m permeability, m 2 Production Casing permeability, m 2 1.0E E E E E E E E E E E E-15 0 Surface Casing years Casing Casing 0.1 Cement 10 years Cement 1 36 years years Water, Oil and Perforations years CO 2 Production Water Injection 44 years years years years 44 years years Water and Oil RFC lightweight 13.8 Production 57 years 100 years Casing 65 years Corrosion 1000 Inhibiting years Fluid 1400 Injection 100 years Tubing 1400 Bridge 1000 years Plug Depth, m Depth, 5 Horizontal Class G 6.8 lightweight Horizontal Class G 18 lightweight years 0.1 years Corrosion Resistant Inconel Casing CO 2 Injection

58 THEME 4: Risk Assessment; Storage & Trapping Mechanisms; Remediation Measures; HSE FINAL PHASE OBJECTIVE Complete a full field risk assessment of the Weyburn Storage site, Region B C B A B

59 THEME 4: Risk Assessment TWP FINAL PHASE Starting Conditions Transient Stage of Peer Review of Phase I Dataset Reservoir Pressure Peer System reviewed, well known Time line formal process After to EOR establish Uncertainty collection of increasing data and Ti me peri od =? information for use in quantitative/semi-quantitative (determined from risk analysis this is necessary to Pdemonstrate inj 25 MPa ECLIPS E simulation not traceability of the data and contribute to the from GEM simulation) transparency 2000 of the 2038 RA process 2100 Start of End of or 7000 EOR P o 15 EOR MPa later Conduct peer review evaluation of the Base and Alternate Scenario s developed Wellbore in Phase Studies I to ensure integration of the final geoscience/reservoir data into the performance assessment model. There is a need to update GEM and Simulation refine the geosphere model based on the latest interpretation of Detailed to reservoir simulation A geological end of EOR and hydrogeological information B Compare results Base and Alternate Scenario Review END of EOR at 2025 Reconciling GEM Simulation to Reservoir/Geosphere/Biosphere pressure equilibration Modelling Deterministic Issues ECLIPSE RA (detailed Simulation simulations) to pressure equilibration D ECLIPSE Simulation GEM to ECLIPSE data FEP and Scenario Development Midale Compare results transfer F for 5000 yr period C ECLIPSE to CQUESTRA Qualitative Risk Probabilistic E data transfer Assessment RA (parameter for Region uncertainty B: included) (AT PRESS URE EQUILIBRIUM) CQUESTRA Simulation Weyburn G for 5000 yr period

60 THEME 4: Risk Assessment TWP Qualitative Risk Assessment Conduct a semi-quantitative RA utilizing experts and Phase I work in order to frame the entire risk assessment process. This will engage a multidisciplinary panel of experts and stakeholders for input ranging from reservoir mechanics to hydrogeology to air quality/human health, public policy and regulations. The goal is to complete even a qualitative risk assessment that identifies the major issues that include both likelihood and consequence and provide a framework for configuring the more detailed and comprehensive analysis tasks required for completion of a quantitative risk assessment. Bow-Tie Method URS Method (Australia)

61 Bow-Tie Method Escalation Factor Escalation Factor Control Barriers sit between Threats and the Top Event, on the Left Hand Escalation Factor Side of the BowTie. Control Escalation Factor Consequence Hazard and Hazard Source Threat Threat Barrier Barrier Barrier Barrier Top Event RPM RPM RPM RPM Consequence Threat Barrier Barrier RPM RPM Consequence Activities Tasks Business Model HSE Critical Task

62 Assessing Risk in CO 2 Storage Projects RISQUE Method (Bowden and Riggs, APPEA Journal, 2004) The expert panel is a critical resource in the RISQUE method. The quality of information used in the assessment is dependent on the level of skill and knowledge of the expert panel and to a lesser extent, on the ability of the risk analyst to effectively guide the panel through the process. Quantification of Likelihood Bowden, A R, Lane, M R and Martin, J H, Triple Bottom Line Risk Management Enhancing Profit, Environmental Performance and Community Benefit, Wiley and Sons, New York.

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64 Final Phase of IEA GHG Weyburn-Midale CO 2 Storage and Monitoring Project Non-Technical Component REGULATORY Clear, Workable and Science-based Regulations for CO 2 Geologic Storage PUBLIC COMMUNICATIONS Public Awareness Driven by the need for better public awareness of CO2 geological storage, especially on the issue of safety. FISCAL POLICY Technical Components GEOLOGICAL INTEGRITY WELLBORE INTEGRITY STORAGE MONITORING METHODS (Geophysics & Geochemistry) RISK ASSESSMENT; Storage and Trapping Mechanisms; Remediation Measures; Environment, Health and Safety C B A B

65 IEA GHG Weyburn-Midale CO 2 Storage and Monitoring Project Rick Chalaturnyk Geological Storage Research Group Department of Civil and Environmental Engineering University of Alberta Schlumberger-MIT Conference April 23-24, 2007