Evaluation and modelling of the response of gas hydrate
reservoirs to changing environmental conditions across
a high‐latitude continental margin
Thomas MESTDAGH
Renard Centre of Marine Geology
Department of Geology, Ghent University Krijgslaan, 281 S8
9000, Gent, BELGIUM
Thomas.Mestdagh@UGent.be
I. INTRODUCTION
Collett et al. (2009)
Winters et al. (2002)
= Only stable
at low T & high P Evaluation and modelling of the response of gas hydrate reservoirs to changing environmental conditions across a high‐latitude continental margin – Thomas.Mestdagh@UGent.be
2
II. OBJECTIVES
Role of climate‐sensitive gas hydrate reservoirs in global climate
Positive feedback mechanism impacting
on the carbon cycle and global climate? (past – present – future)
Changing
environmental
conditions (T,P)
Impact on global
climate
Dissociation
of gas hydrates
Transfer of methane
(+CO2) to
atmosphere
Evaluation and modelling of the response of gas hydrate reservoirs to changing environmental conditions across a high‐latitude continental margin – Thomas.Mestdagh@UGent.be
3
II. OBJECTIVES
Role of climate‐sensitive gas hydrate reservoirs in global climate
Positive feedback mechanism impacting
on the carbon cycle and global climate? (past – present – future)
Changing
environmental
conditions (T,P)
Impact on global
climate
Dissociation
of gas hydrates
Transfer of methane
(+CO2) to
atmosphere
Evaluation and modelling of the response of gas hydrate reservoirs to changing environmental conditions across a high‐latitude continental margin – Thomas.Mestdagh@UGent.be
3
II. OBJECTIVES
Role of climate‐sensitive gas hydrate reservoirs in global climate
Positive feedback mechanism impacting
on the carbon cycle and global climate? (past – present – future)
Changing
environmental
conditions (T,P)
Impact on global
climate
Dissociation
of gas hydrates
Transfer of methane
(+CO2) to
atmosphere
= Sensitivity of gas hydrate reservoirs to
changing environmental conditions:
•
•
•
•
How fast
Where
To which extent
In which fashion
do gas hydrates dissociate?
Evaluation and modelling of the response of gas hydrate reservoirs to changing environmental conditions across a high‐latitude continental margin – Thomas.Mestdagh@UGent.be
3
III. METHODS
Building a model 1. Constrain
initial subsurface
configurations
2. Model temperature and
pressure (sea
level) changes
3. Simulate
resulting hydrate
dissociation
across a high‐latitude continental margin
Evaluation and modelling of the response of gas hydrate reservoirs to changing environmental conditions across a high‐latitude continental margin – Thomas.Mestdagh@UGent.be
4
IV. CONCLUSIONS
Variation in sensitivity of gas hydrate reservoirs across a high‐latitude continental margin
Fairly stable: limited hydrate
dissociation within 100 kyr
Most sensitive: significant hydrate
dissociation within 100 kyr
Most stable: (almost) no hydrates
dissociate within 100 kyr
Evaluation and modelling of the response of gas hydrate reservoirs to changing environmental conditions across a high‐latitude continental margin – Thomas.Mestdagh@UGent.be
5
IV. CONCLUSIONS
The role of melting gas hydrates in climate change Changing
environmental
conditions (T,P)
10s to 100s of kyr
Impact on global
climate
• No large feedback effect with
warming climate
• No significant role for melting gas hydrates in global climate
•
Slow •
Small volumes
Dissociation
of gas hydrates
Transfer of methane
(+CO2) to
atmosphere
Even smaller volumes of methane
6
Thank you!
References
Collett, T.S., Johnson, A.H., Knapp, C.C. and Boswell, R., 2009. Natural Gas Hydrates: A Review. In: T.S. Collett, A.H. Johnson, C.C. Knapp and R. Boswell
(Editors), Natural gas hydrates ‐ Energy resource potential and associated geologic hazards: AAPG Memoir 89, pp. 146‐219.
Kerr, R.A., 2010. 'Arctic Armageddon’ Needs More Science, Less Hype. Science, 329: 620‐621.
Winters, W.J., Lorenson, T.D. and Paull, C.K., 2002. IMAGES VIII/PAGE 127 Gas hydrate and paleoclimate cruise on the RV Marion Dufresne in the Gulf of Mexico, 2 – 18 July 2002: Introduction. In: Winters, W.J., Lorenson, T.D. and Paull, C.K. (Editors), Initial report of the IMAGES VIII/PAGE 127 Gas hydrate
and paleoclimate cruise on the RV Marion Dufresne in the Gulf of Mexico, 2 – 18 July 2002: U.S. Geological Survey Open‐File Report 2004‐1358.