through sub-sea gas systems Dr. Uri Schattner Dept. of Marine - - PowerPoint PPT Presentation

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through sub-sea gas systems Dr. Uri Schattner Dept. of Marine - - PowerPoint PPT Presentation

Feb 04, 2023 120 likes •530 views

Climatic response to forced regressions through sub-sea gas systems Dr. Uri Schattner Dept. of Marine Geoscisnecs Charney School of Marine Sciences University of Haifa, Israel Posamentier and Morris, 2000 Climatic response to forced

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Climatic response

to forced regressions throughsub-sea gas systems

  • Dr. Uri Schattner
  • Dept. of Marine Geoscisnecs

Charney School of Marine Sciences University of Haifa, Israel

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Posamentier and Morris, 2000

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Climatic response to forced regressions through sub-sea gas systems

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2010 2012 2012

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Thanks to

John K. Hall Barak Herut Revital bookman Gal Hartman Ronnie Sade Orna Buch Arik Golan DMG students

R/V Shikmona Giora Boxer R/V Eziona Gideon Amit

Support and funding: Charney School of Marine Sciences Margaret Kendrick Blodgett Foundation Paradigm Geophysical, Kingdom Suite, Schlumberger Petrel, ILDC and Modi’in Energy and GGR

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Schattner and Lazar, 2009

Multi-channel section – gas chimney

Seafloor

Seismic attribute analysis:

Amplitude Similarity

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After Sade et al., 2006

Backscatter  suspected pockmarks

Pockmarks?

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After Sade et al., 2006

1000 m

Bathymetry  suspected pockmarks

?

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Schattner et al., 2010 After Sade et al., 2006 After Schattner et al., 2006

Data

5 VHR new surveys 4 MCS available surveys

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0.9 m 0.6 m 4.6 m 6.3 m 1.6 m 0.3 m 3.0 m 1.2 m

Sparker Hydrophone

30.0 m

Single channel survey configuration

Hydrophone

7.2 m 37.4 m 0.9 m 37.4 m

Sparker

GeoSpark 200 sparker by GeoResources

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Schattner et al., 2010

Data types

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Schattner et al., 2012

Gas seeps – at ~75m depth

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Schattner et al., 2012

Low cohesion – at ~35m depth

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Schattner et al., 2012

Low cohesion

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Findings

Seafloor 720 suspected pockmarks Active seeps – 3 consecutive years Low cohesion zone Subsurface Bright spots Gas masking

 Gas front - ~72 km2

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Schattner and Lazar, 2009

Widespread indications

for cold seeps

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Gas signature

Reservoir / emission Path Source Climatic implications Permeability Lithology + conditions

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Gas chimney 2 major unconformities

Schattner et al., 2012

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Gas chimney 2 major unconformities

Schattner et al., 2012

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Mid Pleistocene unconformity

Harari, 2010, MSc Well interpretation – Derin, 2002

m m

Shallow neritic Shallow neritic Shelf Pleistocene Plio-Pleistocene Pliocene Senonian-Miocene Qishon Yam 1 Depth (m) Two way time (Msec)

Mid Pleistocene unconformity

250 m

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Correlation between seismic markers – unconformities and sea level

After Paillard, 2006; Lisiecki and Raymo, 2005 Relative sea level (m) Time (1000xyears BP)

Mid Pleistocene transition

Harari, 2010, MSc

Two way time (Msec)

1 km

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Gas emission response to sea level change

Sea level drop Exposure Wetland formation Drainage channels Possible source for

  • rganic matter

Rapid channel fill Channel incision Likely correlation to glacial maxima Burial of organic rich sediments

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Gas emission response to sea level change

Sea level drop Removal

  • f

hydrostati c pressure Gas release Warming Sea level rise (highstand) Seepage burial under water and sediments Seepage to atmosphere stops Negligible warming effect Lambeck and Chappell, 2001

Relative sea level

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Schattner et al., 2010

Exposure during LGM

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LGM negative climate feedback

  • The active gas system -- not unique to offshore Israel
  • It represents the usually underestimated marine methane

contribution from mid-latitude continental shelves into sea water and maybe into the atmosphere.

  • Global warming and sea level rise induces a negative,

restraining feedback for gas emission across mid- latitude continental margins

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Data

Lazar, Schattner and Reshef, 2012

2D seismic reflection – time migrated 3D seismic reflection – pre-stack depth migrated

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Lazar, Schattner and Reshef, 2012

WNW ESE

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Giant pockmark

Lazar, Schattner and Reshef, 2012

Formed on Messinian seafloor

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Lazar, Schattner and Reshef, 2012

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Base Messinian

Lazar, Schattner and Reshef, 2012

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Base Messinian over Jonah structure

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Lazar, Schattner and Reshef, 2012

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Top Messinian

Lazar, Schattner and Reshef, 2012

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Top Messinian

Lazar, Schattner and Reshef, 2012

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Mid-Messinian climatic shift

Rouchy and Caruso, 2006

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Climate is not the direct cause of the Mediterranean desiccation

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Climate feedback

Tectonic forces Isolation of Mediterranean Messinian Salinity Crisis Massive drop in sea level Exposure of seafloor Spontaneous gas emission Emission of gas to shallow sea and atmosphere Warming  Mid-Messinian climatic shift Increased runoff from land areas Terrigenous sediment supply + increased channel incision Gas seepage continues as long as sea level is low Tectonic

  • pening of

Gibraltar Major flood Covers seafloor with water and sediments Stops emission to atmosphere

+

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Conclusions

 Continental shelf – gas system active

today

 Basin – Messinian gas emission  Widespread seepage  Negative climatic feedback cycles

 Shelf – LGM  Basin – Mid Messinian climatic shift

 Climatic response to forced regressions

through sub-sea gas systems

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Thank you