Geophysical Monitoring Researches for CO 2 Geological Storage. Shinsuke NAKAO Geological Survey of Japan, AIST

Transcription

1 Geophysical Monitoring Researches for CO 2 Geological Storage Shinsuke NAKAO Geological Survey of Japan, AIST 1

2 2 OUTLINE Introduction Multi-lateral Background, Objectives Geophysical Monitoring Researches 1. Multi-lateral Monitoring at U.S. SWP site 2. Development of Optimal Modeling Technologies (Post-Processors) Numerical Case 1: Tokyo Bay area Numerical Case 2: SWP site

3 Background of AIST s Monitoring Study Balance of safety and reasonable low cost : for practical use of CCS (From web-site of JCCS) Sub-seabed formation near coast Cost-cut in Monitoring is needed Reduction of number of 3D seismic reflection survey operation [ AIST ] Combination of - using various passive signal (multi-geophysical monitoring) & - optimal modeling technique, in order to be complement of 3D seismic survey 3

4 Concept of Complement of seismic reflection survey Geophysical Monitoring methods with Passive Sources Collaboration with LANL, SWP SP: AE: Gravity: (Resistivity): Our Goal: 3D Ref. 3D Ref. 3D Ref. 3D Ref. 3D Ref. 3D Ref. 3D Ref. CO2 Injection: 1 st year 5 th year 10 th year.. Stop injection Post site closure 3D Ref. 3D Ref. 3D Ref. 3D Ref. Reduction of total monitoring cost Building reliable underground model in short period by AIST s study - Reduction of number of seismic survey by multilateral monitoring - Shorter duration time to complete site closure

5 5 OUTLINE Introduction Multi-lateral Background, Objectives Geophysical Monitoring Researches 1. Multi-lateral Monitoring at U.S. SWP site 2. Development of Optimal Modeling Technologies (Post-Processors) Numerical Case 1: Tokyo Bay area Numerical Case 2: SWP site

6 Passive signal utilization: Gravity, Self-potential (SP), Acoustic Emission (AE/MS) Gordon creek, Jul./2011) 6

7 7 Hybrid (Precise continuous & Spatial repeated) Gravity Measurement Corresponding to underground mass change Gordon creek, Feb./2011) (Super conductive gravity meter) (Schematic of observatory) Combination of observations between - Spatial gravity variation (by multi point repeated measurement) & - Temporal gravity variation (by continuous precise gravity monitoring) (in order to understand and diminish various non CO2 effects on observed data)

8 Self-Potential (SP) Monitoring Interpretation and characterization of Underground fluid flow modeling Profile survey Profile survey (wide area, repeat, time-lapse) Measure SP distribution caused by subsurface fluid flow, conductive structure etc. Part of SP data was transmitted through satellite connection Continuous monitoring Continuous monitoring (At specific region, long-term continuous) Precisely detection of temporal change of SP Caused by underground changes such as flowing and chemical effect around observed borehole In SWP Phase-II (Aneth site), view of SP monitoring 8

9 Acoustic Emission (AE/MS) Pressure propagation and Geomechanical response Often independent from CO2 plume image or geological anticipation (Potential leakage path, Weak structures in reservoir, Response from apparent fault) & Surface Downhole (Soma and Rutledge, Aneth (SWP Phase-II): Small number of Master analysis + Relative analysis of all others More reliable AE location 9

10 10 5 years study plan ( ) along with US s Southwest Regional Partnership To evaluate applicability of non-seismic passive method If they can realize model-based monitoring approach. << Highlights of Plan >> - At Gordon Creek, that is Deep Saline Aquifer CO2 test site - Gravity: Hybrid measurement between spatial (relative) and temporal (absolute and/or precise continuous relative) measurement with Super Conductive Gravity meter - Self-Potential: Spatial profile and long-term continuous. Precise interpretation by using Post processor (forward modeling approach) - AE (MS): Combined data analysis of both deep downhole (SWP) and surface measurement (AIST)

11 Self-potential (mv) Gordon Creek ( Uinta Basin) Multi-lateral Geophysical Monitoring (cont.) In FY2011, what we have done: 1.Installation of observation stations for gravity, SP and AE at Gordon Creek test site 2. Start of baseline measurement SP profile survey: AE: Gravity: Elevation (m WGS84) DOE s Policy Change ( to CCUS ) Deep Saline Aquifer EOR Site (Farnsworth, Texas) 11

12 12 OUTLINE Introduction Multi-lateral Background, Objectives Geophysical Monitoring Researches 1. Multi-lateral Monitoring at U.S. SWP site 2. Development of Optimal Modeling Technologies (Post-Processors) Numerical Case 1: Tokyo Bay area Numerical Case 2: SWP site

13 13 (2)Development of Optimal Modeling Technologies (Post-Processors) Objective To obtain a reliable reservoir model, history-matching data are necessary as much as possible. To utilize geophysical monitoring data for history matching purpose: We need to develop post-processors calculating observable geophysical data from output (CO2 saturation, T and P changes) of reservoir simulation Monitoring(Observation data) Well data Downhole pressure Downhole Temp. etc. Geophy. Mon. data Seismic Resistivity Gravity SP changes etc. Direct history-matching is possible Revision of the simulation model In order to conduct History-matching Simulation of CO2 injection Postprocessors P., T. CO2 saturation Chemical Contents Changes 観測井 圧入井

14 14 Merits of geophysical monitoring simulation using geophysical post-processor Refine subsurface model for better understanding/forecasting CO 2 movement Quick detection of unexpected CO 2 movement Difference between real monitoring data and PP outputs suggest some unexpected event Optimum design of monitoring network Calculate outputs from virtual monitoring network based on an existing model

15 Numerical Case (1) Storage into deep aquifers below Tokyo Bay area Total grid blocks: 30 x 16 x km In the central region, the bock size is x= 500 m y= 500 m z= 100 m CO2 injection into deeper Umegase formation 10 million tons per year for 0 < t < 50 years Contour (yellow) : depth to the top of Umegase formation Grid (red) : Numerical Model for the simulation Rectangel(orange) : injection area Reservoir simulator: STAR EOS: CO2SQS 15

16 Result of the numerical simulation for the Tokyo-Bay model Total mass CO2 injection: 10 million tons per year A 2.5 km x 10 km A Gaseous Dissolved Liquid Storage Capacity Estimation: ~ 7Gt Liquid CO2 Super-critical residual CO2 (Ishido et al., 2008) 16

17 Simulation of geophysical monitoring for the Tokyo-Bay model MT apparent resistivity :above the center of injection Gravity change : plan view after 50 yrs injection (L) and borehole measurement at 3km east from the injection (R) SP :along the NW-SE profile after 5 yrs injection. 100mV (Nishi et al., 2009; Sugihara and Ishido, 2009) 17

18 Numerical Simulation of Repeated Seismic Relection Survey 5yrs after injection start : large amplitude reflected waves due to clear boundary of super-critical CO2 with small dispersion Longer injection increase of the volume of super-critical CO2 clear reflection from the upper & lower boundary of CO2 region. longer interval between the reflected waves. A A t = 5 yr t = 25 yr t = 50 yr A A (Ishido et al., 2008 ; Nishi et al., 2009) 18

19 Numerical Case (2) Storage into deep aquifers at SWP site Horizontal: 6km x 6km Depth: 0m-1300mRSL 1M tons/yr Injection for 11 yrs into Entrada Sandstone Based on the model by Utah Univ. 800m Total CO 2 Gaseous t=2yr(after 1yr Injection) Dissolved t=11yr(after 10yr injection ) t=4yr(after 3yr Injection) CO 2 Saturation,Temperature, Pressure t=12yr(1yr after stop) 19

20 20 Case (2) SWP site: Simulation of Seismic Reflection P wave velocity vs. CO 2 saturation, given by patchy saturation model Seismic section across the injection zone (station no.= 13) along 4 km-long line after 3 years of CO 2 injection.

21 Gravity change(μgal) Gravity change(μgal) Case (2) SWP site: Simulation of Gravity Depth (0 to 2260 meters) Depth (0 to 2260 meters) Depth(m) Measurement at ground surface Borehole Measurement At ground surface, gravity changes are very small around 1 μgal after 3yrinjection at the center of injection (upper) and 450m apart from injection (lower) Borehole gravity (observation well) 3 yr injection Time (days) High sensitivity, nano-scale measurement is necessary at ground surface Change in gravity (-15 to 20 Gal) Borehole gravity response in the injection well (right) and observation well (left) after 3 years of CO 2 injection. Borehole gravity (injection well) 3 yr injection These changes are detectable by using borehole gravimeter Time (days) Change in gravity (-60 to 60 Gal) 21

22 22 Summary AIST s monitoring research activities at SWP site: Multi-lateral geophysical monitoring (Gravity, Self-potential, Acoustic Emission) with considering modeling in order to be complement seismic survey. Our study is targeting the SWP s CO2 injection which is expected to start in 2013 at the EOR site in Texas. Numerical simulations were performed to estimate changes in quantities observable using geophysical survey techniques (self-potential (SP), seismic reflection, MT and gravity) caused by CO 2 injection into an aquifer. Results suggest that all techniques can discern operations-induced changes in the aquifer. Of course, the applicability of any particular method is likely to be highly site-specific, but these calculations indicate that none of these techniques should be ruled out altogether. Some surveys (gravity, MT) appear to be suitable for characterizing the longterm changes, whereas others (seismic reflection, SP) are quite responsive to the short-term disturbances.

23 23 Thank you for your attention These research works were funded and supported by Ministry of Economy, Trade and Industry (METI). Shinsuke NAKAO Institute for Geo-Resources and Environment (GREEN) National Institute of Advanced Industrial Science and Technology(AIST)