1
Droplet Diameter, mm This model will show the impact of tidal flows, ocean currents and bathymetry on the dispersion and distribution of the small scale bubble plume and seawater chemistry changes. The model shall also have an extension into the sediments to predict the leakage flow through the rock and geological structures to the seabed, predicting leakage rates, timeframes and positions. In the water column the changes depend on the leakage scenario. Under the most extreme scenarios, a localised maximum pH change of -2.5 is recorded in a well blowout scenario (from the ECO 2 project), where pH changes greater than 0.1 are witnessed within a few hundred meters of the leakage zone. pH Affected Areas Smaller leakages (QICS experiment as an example) can however by more difficult to detect, prolonging the effects if the leak was to continue over the longer term. DIC pCO 2 , μatm Scientific investigations on the management and estimation of leakage have been conducted by the projects, including SECURE, ECO2, and QICS among many others. The recently funded STEMM-CCS project is going to develop a small in-situ leakage experiment in the North Sea, in an environment that has the potential for carbon storage in the UK. Partners Marius Dewar Baixin Chen [email protected] [email protected] Numerically Modelling the Seawater and Bubble Plume Interactions to Determine the Physicochemical Impact of CO 2 Leakage into Open Marine Waters Institute of Mechanical, Process and Energy Engineering Heriot-Watt University, Edinburgh References [1] Photos taken at Panarea by Giorgio Caramanna. [email protected] [2] Experimental and modelling work by Lisa Vielstädte and Peter Linke published in: Alendal. et al., Technical synthesis report on droplet/bubble dynamics, plume dynamics and modelling parameters, use of hydro-acoustics to quantify droplet/bubble fluxes, and carbonate system variable assessment” ECO2 Deliverable, D3.1. , November 2013, DOI 10.3289/ECO2_D3.1. [3] Photo taken by Henrik Sthal, Available from QICS: Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage. www.bgs.ac.uk/qics 2016. [4] STEMM-CCS: Strategies for Environmental Monitoring of Marine Carbon Capture and Storage | STEMM-CCS. http://www.stemm-ccs.eu 2016. [5] Image of the BOM model, published in: G. Alendal, M. Dewar, A. Ali, Y. Evgeniy, L. Vielstädte, H. Avlesen, and B. Chen, “Technical report on environmental conditions and possible leak scenarios in the North Sea” ECO2 Deliverable, D3.4. , November 2014, DOI 10.3289/ECO2_D3.4. [6] The bathymetric image has been taken from the EMODnet Bathymetry portal - http:// www.emodnet-bathymetry.eu. This portal was initiated by the European Commission as part of developing the European Marine Observation and Data Network (EMODNet). [7] B. Metz and Intergovernmental Panel on Climate Change, Eds., IPCC special report on carbon dioxide capture and storage. Cambridge: Cambridge University Press, for the Intergovernmental Panel on Climate Change, 2005. 1. CO 2 Leakage to the seawater and the subsequent impacts on the marine environment are serious concerns for development of offshore geological carbon storage. [1] Governing Equations Plume Exchange Terms Mass Transfer (dissolution) Momentum Transfer (drag force) Interactions (coalescence) (breakup) , , k i k k k k k q x u t j Dependant Variable Source Terms k , k q 2 , 2 , 1 2 , 0 , 0 , , , , ) ( ˆ 0 2 , 2 1 2 1 CO d j i i i d CO w Mass Salinity e Temperatur Y S T F g x u x x P velocity Seawater u F g velocity Bubble u density Number n w mass Bubble i i 0 3 / 2 3 / 1 6 2 C C D Sh n w s f CO j j j j d u u u u C n F 1 2 1 2 3 / 1 3 / 2 1 6 8 1 2 / 1 3 / 2 3 / 1 6 / 5 2 / 1 913 . 0 exp * 86 . 2 C d eq c 24 . 1 / 9 . 1 0.80 0.80 3 / 1 3 / 11 2 3 / 1 We d eq c We u b ' 1 . 0 1 1.581 exp 6 . 1 24 . 1 / 1 42 . 0 1 1 1 3 / 11 3 / 1 We d eq b b b c c 3. For high pressure jets, or high volume leakages, the plume height may increase. Droplet leakages, at depths >450 m, will also rise much further; however, they will convert to gas bubbles and fully dissolve in the upper waters. A small scale turbulent ocean two-phase plume model is developed and applied to simulate these effects and fill the gaps left from the in-situ and laboratory experiments. Findings from numerical simulations show that for bubbly leaks seeping from the sediments, the bubbles will dissolve within the first 15 meters, not directly reaching the atmosphere in the majority of situations. Bubble Diameter, mm Bubble Diameter, mm 2. Potential changes to the seawater chemistry, such as DIC, pCO 2 or pH, are vital data to predict the impact to the local marine ecosystem, which includes both benthic and marine organisms; along plant life. 4. In the STEMM-CCS project, the plan is to extend these simulations into the larger scale North Sea waters to investigate these longer term affects through a 3D unstructured- grid non-hydrostatic coastal model (FVCOM). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 654462 [4] [3] [2] [1] [5] [6] [7] Further down to molecular sale Sediments CO 2 Brine
