The Lake Laach region as monitoring test site

Transcription

1 The Lake Laach region as monitoring test site Ingo Möller October 17-19, 2011 Maria Laach, Germany 2 nd CGS Europe Knowledge Sharing Workshop Natural Analogues

2 Acknowledgements Many thanks to Kai Spickenbom Christian Seeger Dave Jones BGR: Eckhard Faber, Martin Krüger, Dietmar Laszinski, Franz May, Jürgen Poggenburg, Nicole Rann, Stefan Schlömer, Christian Wöhrl BGS: Tom Barlow, Patricia Coombs, Kay Green, Bob Lister, Jonathan Pearce, Richard Shaw, Michael Strutt, Julian Trick, Ian Webster, Julie West LUWG (Mainz): Olaf Prawitt NIAH: Volker Böder, Harro Lütjens, Arne Sauer Inst. Geosciences (Univ. Mainz): Frank Sirocko & staff URS: Giorgio Caramanna, Salvatore Lombardi others: Michael Uhlenbruch, Ansgar Hehenkamp, Benedictine Abbey of Maria Laach, SGD Nord (Koblenz)

3 Rationale Deployment of geological CO 2 storage implies the capability to detect possible leakage from reservoirs and eventual effects on the environment, especially the biosphere including human health Monitoring as essential system component within the planning, selection, installation and operation of geological CO 2 storage sites Monitoring performance must ensure different methodological components: Detection Verification & characterization of spots suspicious to leakage Long-term-Monitoring in case of confirmed releases Only a selected combination of different methods and technologies can fulfill these necessities

4 Regional setting Lake Laach is one of the volcanic centres of the East Eifel volcanic field Located in the uplifting Paleozoic Rhenish Massif which represents the Devonian basement Its eruption at about yr bp is the only known large explosive eruption in Central Europe during late Quaternary Neighbouring quarternary volcanic centres are at Rieden and Wehr Like at Lake Laach, their eruptions (Rieden: ~ ka, Wehr: ~ ka) have formed calderas Other dominant features: cinder cones and related lava flows, ignimbrites & volcanic ash and tuff

5 Precondition: Presence of CO 2 Dissolved carbon species and free CO 2 reach the surface at many places in the East Eifel volcanic field (and other regions of the Rhenish Massif) Isotope analyses (noble gases and carbon) show a geogenic origin of the CO 2 It is linked to the magma source of the volcanic fields which is located in the upper earth mantle, in an area of reduced seismic velocities, known as Eifel Plume There, magnesium rich magmas, which are formed by partial melting of peridotite, take up CO 2 and release it during ascent in the lower earth crust (due to pressure release and cooling of the magma) In the fractured upper earth crust, CO 2 migrates along the margins of basement blocks and faults, where it comes in contact with groundwaters. Water-rock interactions consume some of the CO 2 (transformation into dissolved bicarbonates and solid carbonates)

6 Mofettes Dry mofettes Carbonic and other mineral springs Environmental leakage indicators CO 2 -influenced life communities Deep CO 2 reservoirs & industrial analogues

7 Mofettes 10m Surface survey Large-area sidescan sonar survey Underwater ROV survey

8 Mofettes Long-term gas flux monitoring experiment Lake Laach 2011 April 5, 2011 water depth: 7.8 m September 19, 2011

9 Mofettes Long-term gas flux monitoring experiment Lake Laach 2011 r = 0.3 r = r = 0.65 Gas flow rate (running hourly mean) vs. water temperature, air pressure (not corr.) & wind speed

10 Mofettes Dry mofettes Vent 1 Lake Laach, western side δ 13 C values CO 2 (Vol%) Large-scale perspective

11 Mofettes Dry mofettes Langer (1988) Small-scale perspective

12 Mofettes Dry mofettes Carbonic and other mineral springs e.g. cold water geysirs

13 Pferdebrunnen CO 2 gas : Vol-% δ 13 C CO2 : -4.7 to -3.8 HCO - 3 : 1010 mg/l ph : 5.78 Conductivity: 1265 µs/cm Oxygen saturation: mg/l Redox potential: mv Römerbrunnen CO 2 gas : Vol-% δ 13 C CO2 : -4.6 to -5.1 HCO - 3 : 1820 mg/l ph : 6.39 Conductivity: 2480 µs/cm Oxygen saturation: 5.6 mg/l Redox potential: 35 mv e.g. captured springs

14 Mofettes Dry mofettes Carbonic and other mineral springs Environmental leakage indicators Wehr Small-scale perspective

15 Mofettes Dry mofettes Carbonic and other mineral springs Environmental leakage indicators Fe(III)-oxides Stands of Carex sp. in dry, terrestrial habitats

16 Mofettes Dry mofettes Carbonic and other mineral springs Environmental leakage indicators CO 2 -influenced life communities Large-scale perspective

17 Mofettes Dry mofettes Carbonic and other mineral springs Environmental leakage indicators CO 2 -influenced life communities Deep CO 2 reservoirs & industrial analogues

18 Results of the CCS-related R&D work onshore offshore Example: Stable carbon isotopes from CO 2 gas Clear isotopic distinction between deep, inorganic CO 2 and shallow, biological CO 2 (though atmospheric influence, mixture & fractionation) Normally, CO 2 generated from burning fossil fuels have isotopic signature well differentiated from environmental C isotope values. However, some CO 2 species might have an isotopic signature which is similar to that of shallow biogenic CO 2

19 Results, continued A good number of established and reliable methods and tools exist for the near surface monitoring at CO 2 storage sites regarding gas monitoring bio monitoring (micro and makro cosmos) eco monitoring (populations and systems) They represent a huge toolbox for confidence building; confidence in technology with regard to markets and the public (confidence acceptance)

20 Results, continued Development & evaluation of suites of techniques enabling small-scale surveys to detect eventual leakage pathways on a regional level (and to contribute to baselines) a rapid surveying of relatively large areas and the derivation of essential results in short time (and even real time) detailed large-scale verification and characterization procedures for selected study sites the use of local knowledge to target possible sites of gas migration and/or release continuous monitoring and discrete measurements Definition of a flexible multi-level approach for the (near surface) monitoring at CO 2 storage sites of different types: Detection Verification Characterization Long-term monitoring

21 Lessons-learnt Reliable techniques exist that can distinguish deep, geogenic CO 2 from shallow, biogenic CO 2 Leakage, if it occurs, can be quantified by detailed flux measurements Permanent gas monitoring stations are able to observe short-term variations and to differentiate anomalies from the background The detection of CO 2 gas is able to resolve even low levels Once detected, the quantification accuracy is still orders of magnitude higher; less than t per year, i.e. less than 5 10 g per day

22 Lessons-learnt, continued What we need is: Baseline monitoring (besides monitoring during operation) that reveals natural (e.g. seasonal) variations for relevant objects explains the determining factors of these variations seems to be specific for individual storage sites starts well before the first CO 2 injection just to have sufficient time for the interpretation of recorded data Systematical link between (the results of) near surface and subsurface monitoring efforts