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| Titel |
Comparison of the impact and fate of leaked CO2 and CH4 bubbles from the seabed on the near field waters within the North Sea. |
| VerfasserIn |
Marius Dewar, Wei Wei, Sorush Khajepor, David McNeil, Baixin Chen |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250080677
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| Zusammenfassung |
| Simulating the formation, dynamics and dissolution of various gas bubbles, such as methane
(CH4) and carbon dioxide (CO2) in seawater allows the physiochemical impact on the marine
environment to be measured. This study develops both an individual bubble model to
determine the bubble fate; along with a small scale, two phase, three dimensional
LES numerical plume model to measure the impact on the waters from a bubble
leakage from natural reservoir vents and potential storage sites within the North
Sea.
The objective is to predict the effect that these leaks have on the local marine
environment. Both models and sub-models are calibrated using either laboratory or in-situ
experimental data for each gas, such as shrinking rate and rising velocity. Implementing fluid
properties and seasonal data from the potential CO2 leakage and CH4 venting location sites,
such as temperatures, salinity, currents and leakage depths, allow accurate tuning of the
model. Recent temperature and salinity profiles within the North Sea local to the
potential sites are recorded [1], where circulation models provide a prediction of
the local ocean currents [2] and seepage rates are taken based on observational
data.
Sub-models are implemented that predict the momentum through drag forces and mass
transfer through convective transportation from the bubbles to the seawater allowing the
prediction of the velocity and shrinking rate of the individual bubble and the two phase model
allows the dynamics and concentration of dissolved gas solution in seawater to be predicted.
Correlations for these are presented based on experimental data from Bigalke et al. [3, 4]
among others.
Case studies for both gasses will provide preliminary results that can be compared with
observational data in terms of both plume and individual dynamics verifying the validity of
the model findings that can be extended into mesoscale, regional and global scales to see the
true effect on the environment. Findings show that CH4 is far less soluble than
CO2 and rises higher into the waters; as such there is a greater effect on the marine
environment from the dissolved CO2, but a large risk from the CH4 bubbles rising into the
atmosphere.
References:
[1] Coriolis, Coriolis : In situ data for operational oceanography. [online] Available at:
[Accessed 16 February 2012].
[2] Delhez, E.J.M and Martin, G. Preliminary results of 3D baroclinic numerical models
of the mesoscale and macroscale circulation on the North-Western European Continental
Shelf, Journal of Marine Systems, 1992. 3, 423–440.
[3] Bigalke, N. K., Enstad, L. I., Rehder, G. and Alendal, G. Terminal velocities of pure
and hydrate coated CO2 droplets and CH4 bubbles rising in a simulated oceanic
environment, Deep-Sea Research Part I-Oceanographic Research Papers, 2010, 57(9),
1102-1110
[4] Bigalke, N. K., Rehder, G. and Gust, G. Experimental Investigation of the Rising
Behavior of CO2 Droplets in Seawater under Hydrate-Forming Conditions, Environmental
Science & Technology, 2008, 42(14), 5241-5246. |
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