Development and proof for monitoring technique of sub-seabed CCS

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1 Development and proof for monitoring technique of sub-seabed CCS Kimonori Shitashima IEAGHG 2 nd Combined Meeting of the Modelling and Monitoring Networks 6-8 July 2016, Edinburgh

2 Detection/monitoring of CO 2 leakage from sub-seabed CO 2 storage into the seabed geological formations has being studied as one of possible options to mitigate the accumulation of anthropogenic CO 2 into the atmosphere. The key focus of environmental assessment for CCS is detection and monitoring of the CO 2 leakage from seafloor. Therefore, development of new cost-effective detection and monitoring techniques is essential to evaluate the effectiveness of CCS. In addition, impacts on the ocean environment including marine ecosystem should be assessed.

3 Development of equipment and technique for detection/monitoring of CO 2 leakage We have been developing observation equipment and technologies for the purpose of assessing environmental impact of CCS by sea-going observation. 1. Detection of CO 2 leakage from seafloor. 2. High precision in-situ measurement of ph and pco Mapping of leaked CO 2 from seafloor. 4. Short-term and/or long-term monitoring of diffusion behaviors of leaked CO 2.

4 Case 1: Direct leakage of stored CO 2 into the ocean 1) Detection of CO 2 leakage at the CO2 storage site over a wide seafloor area. 2) Identification of CO 2 leakage point using detectable instruments. 3) Confirmation of CO 2 Sediment (unconsolidate) Sediment (consolidate) Seal layer CO 2 storage layer CO 2 leakage Geological fault Geological fault leakage point and condition. 4) Continuous or periodical monitoring of CO 2 leakage condition.

5 Detection of CO 2 leakage over a wide area t 1 Transponder 送受波器 1 A - Application of acoustic tomography technology - Principle of acoustic tomography measurement Θ t 2 流速 V Water flow V 送受波器 Transponder 2 B Acoustic tomography can detect a phenomenon (turbulence of density, such as water flow, hydrothermal, gas bubble and droplet) which has an influence on acoustic propagation velocity between two transponders. The detection of CO 2 leakage over a wide area is possible by deployment of a large number of transponders. 距離 Distance L Transponder A Transponder B V= C 2 Δt 2 L cosθ Δt=t 2 - t 1

6 Sea test of bottom installed acoustic tomography at shallow hot spring site Transduce r Hot spring vent Water depth: 20m 200m Photo of prototype of acoustic tomography transponder Temperature perturbation (ºC)

7 High precision in-situ measurement of ph and pco 2 ph Electrode: Ion Sensitive Field Effect Transistor (ISFET) Reference Electrode: Chloride Ion Selective Electrode (Cl-ISE) ISFET ph sensor Pressure vessel (ø80, 200L) pco 2 sensor Teflon AF Inner solution Li-ion battery Cl-ISE 3 cm Electric circuit board of ph and pco 2 Accuracy: ±0.003pH Response time (at 3000m, 1.8 ): less than 1 second@ph less than 60 seconds@pco 2 pco 2 sensor ph sensor ISFET Shitashima and Kyo, 1998, Shitashima, et al., 2002, Shitashima, et al., cm Cl-ISE Gas permeable membrane: Amorphous fluoropolymer (Teflon AF, DuPont) Inner solution: ca. 3ml of 1.5% NaCl

8 Identification of CO 2 leakage point - Mapping observation by in-situ sensor installed ocean observing platforms - D-GPS antenna Small-AUV (Stand-alone) ADCP/DVL ph/pco 2 /ORP sensor pco 2 ORP Side scan sonar FLNTU ECO Packs+OXGEN Optode G-CTD ph Large-AUV (RS232C) Large-ROV (RS232C) Micro-ROV (RS485) CTDT Sensor ph/pco 2 /ORP Sensor ph/pco 2 /ORP Sensor

9 Monitoring of short-term diffusion behavior of leaked CO 2 - Development of towing multi-layer monitoring system - On board control unit Computer Wireless modem DGPS Control command Data 200m 5m Wireless modem DGPS Submersible towing unit (data/position receiver) 1000~2000m Towing wire 2m Sea anchor Transponder (5 units) (data/position transmitter) SSBL Transducer SSBL system Compass Clinometer Pressure gauge Transponder CTD ph/pco 2 sensor Sinker SSBL Transducer

10 Long-term monitoring of diffusion behaviors of leaked CO 2 - Development of automatic elevator - Eulerian method that one in-situ sensor measures the continuous data by going up and down at the same location is ideal to obtain the temporally and spatially continuous observation data. View of automatic elevator Observation buoy (ph/pco 2 and depth sensors are installed in the inside of the buoy) Sea winch

11 Case 2: Diffusion of of stored CO 2 into the pore water (Not direct leakage into the ocean) In-situ measurement of ph (pco 2 ORP) in sediment Sediment (unconsolidate) Sediment (consolidate) Seal layer Dissolution of heavy metals from sediment CO 2 leakage Geological fault Geological fault In-situ measurement of heavy metals dissolved from sediment in seawater Measurement of acoustic reflection from sediment by sub-bottom profiler In-situ measurement of self-potential/electrical resistivity in sediment CO 2 storage layer Core sampling

12 In-situ ph sensor for sediment In-situ ph in sediment (Natural analogue at deep-sea hydrothermal site, Okinawa Trough) Water depth : 1500m,Water Temp.: 3.5ºC Spear Cl-ISE ISFET In-situ ph of 50cm deep in sediment In-situ ph of 30cm deep in sediment

13 Strategy for detection and monitoring of CO 2 leakage in CCS Detection, identification and confirmation of CO 2 leakage point 1 Detection of CO 2 leakage by seafloor-based acoustic tomography Offshore Platform 2 Narrowing the leakage point by AUV/ROV equipped with chemical sensor 3, Identification and observation of CO 2 leakage condition by ROV Periodical or continuous monitoring of CO 2 leakage condition for long-term Periodic monitoring of CO 2 leakage condition by TMLMS, ROV and water sampling Continuouzs monitoring of CO 2 leakage condition by seafloormounted automatic elevator Shitashima, et al., 2013 Capro ck 2, 3AUV/ROV Acoustic tomography1 Injected CO 2 Reservoir 5 Automatic elevator > 1 km

14 Controlled CO 2 release experiment QICS: Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage Secured container holding CO 2 supply, regulation, alarms. Boat, diver and sensor based monitoring bedrock water ~10 m m sediments ~5 m

15 What did we observe? ph, pco 2, ORP in seawater Real-time monitoring (on-line) near the leakage point Long-term monitoring (off-line) around the leakage point ph, ORP in sediment Mapping of ph, pco 2, etc. in seawater by AUV Mapping of atmospheric CO 2 above the leakage point

16 Real-time monitoring by ph/pco 2 /ORP sensor RS-422 connection m Cable:400

17 Long-term monitoring by ph/pco 2 /ORP sensor

18 Results of real-time monitoring of ph/pco 2 20kg/d CO 2 gas injection rate 80kg/d 150kg/d 200kg/d STOP

19 Long-term monitoring of ph/pco 2 during gas injection Zone-2

20 Zone-1 Zone-2 Long-term monitoring of ph/pco 2 after stopping gas injection

21 Mapping Results of water column and atmosphere water column mapping Atmosphere mapping pco 2 ph ORP Observation Items ph DO pco 2 Current ORP Temp. Chlorophyll Sal. Turbidity Side scan

22 Latitude (N) 150m 190m Mapping Results of water column and atmosphere Low tide (2012/6/20) High tide (2012/6/21) Atmospheric CO 2 (uatm) 410 Atmospheric CO 2 (uatm) Current Wind (breeze) Water column ph 7.76 Wind 390 (weak) 380 Water column ph Current m m 7.88 Longitude (W)

23 Long-term monitoring of ph in sediment Spear ph/orp sensor for sediment Cl-ISE ISFET

24 Results of sediment ph (50cm depth)

25 Tide variation of sediment ph (50cm depth) Date/Time

26 CO 2 leakage in QICS experiment +10~+15µatm 3~4m +20~+25µatm >-0.06pH <-0.02pH -1.5~-2.2pH -1.5~-2.0pH 2m 50cm ~-0.3pH +0.5pH (-1.0~-1.5pH) a) Low Tide b) High Tide Shitashima, et al., 2015 Maeda, et al., 2015

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