The Challenge of Underwater Gas (Leakage) Monitoring

Transcription

1 The Challenge of Underwater Gas (Leakage) Monitoring Ingo Möller Kai Spickenbom, Volker Böder, Martin Krüger IEAGHG workshop on Natural Releases of CO2, Maria Laach, November 2 4, 2010

2 Challenges of underwater CO 2 monitoring Guiding theses: Underwater CO 2 monitoring is an important tool to ensure the effectiveness of geological CO 2 storage, public health and environmental safety must meet legal requirements / has to assure regulatory compliances deals with a difficult, polymorphic subject (4 phases) needs a lot of sophisticated equipment stresses and wears extremely the employed material needs a lot of man power and expertise is expensive is time consuming (vast areas, great depths, lots of data: needle in a haystack )

3 Regulatory compliances Example: EU Commission Decision , Annex XVIII, Activity specific guidelines for the geological storage of CO 2 in a storage site permitted under Directive 2009/31/EC : The amount of emissions leaked from the storage complex shall be quantified for each of the leakage events with a maximum overall uncertainty over the reporting period of 7.5% (from: lex.europa.eu/... uri=oj:l:2010:155:0034:0047:en:pdf). Example: Requirements from insurance companies, operators etc.

4 Basic physicochemical properties of CO 2 CO 2 phase in natural reservoirs is mainly controlled by pressure, temperature, and its solubility in water/brine CO 2 occurs in four different phases CO 2 saturated (sea)water is denser than CO 2 free (sea)water and sinks towards the seafloor CO 2 gas is less dense than (sea)water and migrates upwards

5 Basic physicochemical properties of CO 2 No Bubble? No Trouble However, there is a great chance to detect CO 2 in water due to the physical and/or chemical differences between CO 2 and water, e.g. density temperature ph conductivity salinity from: Chen et al., 2009

6 The right answer is the right concept A realistic underwater gas monitoring of CO 2 storage complexes requires a multi level concept 1. Level: Detection 2. Level: Verification 3. Level: Characterisation Detection Verification Characterisation Inst. f. Seenforschung Periodic surveys by means of ship mounted hydro acoustic methods covering large areas Inspection of anomalies using ROV based techniques Installation of stationary monitoring devices for the long term survey of identified seepages/leakages

7 1. Level: Large area survey (hydro acoustic) Lots of methods with individual advantages and disadvantages are available on the market under development and currently under evaluation, water surface e.g. Single beam echosounders Multi beam echosounders Side scan sonars Acoustic doupler current profilers Subbottom profilers etc. path of rising bubbles time sea bottom Example of a simple fish finder operation

8 1. Level: Multi beam echosounders (e.g. Laacher See) in cooperation with the Northern Institute of Advanced Hydrographics and the Inst. f. Geomatics, HCU Hamburg

9 1. Level: Multi beam echosounders (e.g. Laacher See) Reson Multibeam Echosounder SeaBat 8101: 4000 soundings per sec 240 khz, swath coverage 150 range up to 300 m in width operating depths up to 3000 m

10 1. Level: Example side scan sonar (e.g. Laacher See) C MAX side scan sonar CM 2 digital towfish, Standard dual frequency operation, config.: EDF (325/780kHz) swath range: m (325 khz), m (780kHz) pings per sec (freq. and range depended): 4,8 24,7

11 1. Level: Subbuttom profiler (e.g. Laacher See) Innomar Subbottom Profiler SES 2000 Beamwidth +/ 1,8 Transmitter: prim. freq.: 100 khz, sec. frequencies: 4 15 khz Operating ranges: m depth Penetration: up to 50 m Sampling resolution: > 1 cm Accuracy: 100 khz : 0,02m+0,02 % of water depth 10 khz : 0,04 m + 0,02 % of water depth

12 1. Level: Subbuttom profiler (e.g. Laacher See)

13 2. Level: ROV based verification USBL positioning system 360 Sonar ROV sonar data Laach lake Videocameras Headlights Basis: VideoRay Pro 3 Micro ROV Sniffer for dissolved CO 2 and CH 4 (optical) Modular system rack max. operation depth: 150 m

14 2. Level: ROV based verification (e.g. Laacher See) Preliminary data on gas releases (shallow water, n=143): Mean flow rate per release: 475 ml gas min 1 (= 684 l d 1 ) Mean CO 2 content in gas: ~ 90% Mean CO 2 mass transferred: ~ 1210 g d 1 Example: Mobile gas flow monitoring

15 3. Level: Characterisation / Longterm M. Stationary monitoring system Constanza lake & Panarea equipment

16 3. Level: Characterisation / Longterm M. 16 months continuous operation without a single technical problem!

17 Conclusion Bad news: Various challenges on different levels with regard to regulatory compliances technical aspects (material, construction) operational demands time/timing aspects financial implications Good news: These challenges can be tackled by the right monitoring concept based on a multi level approach with a well selected combination of different methods on different scales

18 What needs to be done? Detection * Mobility * Fast Intervention Systems Integration Robustness * Least Cost

19 Thank you very much for your attention Acknowledgements: We would like to thank Jürgen Poggenburg, Christian Seeger (both BGR), and our colleagues from Institut für Seenforschung/LUBW, Alfred Wegener Institut f. Polar u. Meeresforschung, Northern Institute Adv. Hydrographics GmbH, University of Rome La Sapienza, and Centre for Innovation in CCS for exchange, advice and whatever support. References: Chen, B., Nishio, M., Song, Y. & Akai, M., 2009: The fate of CO2 bubble leaked from seabed. Energy Proc. 1: Greinert, J., 2008: Monitoring temporal variability of bubble release at seeps: The hydroacoustic swath system GasQuant. J. Geophysical Res IFM GEOMAR, 2010: RV Celtic Explorer Cruise Report CE0913. Fluid and gas seepage in the North Sea, Berichte Leibniz Inst. Meereswissenschaften Chr. Albrechts Universität Kiel, Nr. 36. Leifer, I. & Boltes, J., 2005: Turbine tent measurements of marine hydrocarbon seeps on subhourly timescales. J. Geophysical Res pp.