Active seafloor processes in the Levant: observations and potential - - PowerPoint PPT Presentation

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Active seafloor processes in the Levant: observations and potential - - PowerPoint PPT Presentation

Dec 16, 2022 159 likes •544 views

Active seafloor processes in the Levant: observations and potential implications Makovsky Y. (1), G. Tibor (2), B. Herut (2), U. Schattner (1), D.N. Waldmann (1), Spiro B. (1), Sivan O. (3), Antler G. (3), Ballard R.D. (4), Austin J. (4), Coleman

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Active seafloor processes in the Levant:

  • bservations and potential implications

Makovsky Y. (1), G. Tibor (2), B. Herut (2), U. Schattner (1), D.N. Waldmann (1), Spiro B. (1), Sivan O. (3), Antler G. (3), Ballard R.D. (4), Austin J. (4), Coleman D. (4), Tezcan D. (1), Hübscher C. (5), and Ben-Avraham Z. (1).

1. Charney School of Marine Sciences (CSMS), University of Haifa, Israel. 2. Israel Oceanographic and Limnological Research, Haifa, Israel 3. Geological and Environmental Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel. 4. Sea Research Foundation Institute for Exploration, Institute for Exploration, Mystic, RI, USA. 5. Institute for Geophysics, CMCR, University of Hamburg, Hamburg, Germany.

Acknowledgements

IFE and University of Haifa for funding; The Oil Commissioner office for data approval Paradigm for software support E/V Nautilus crew and project participants Noble Energy, GGR, Modiin, Ecolog, Israel Ministry of Energy and water for data and slides John Hall, Israel Bathymetric survey

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SLIDE 2

Sustainable development requires:

  • Data sharing
  • A wide industry-government-academy

collaboration. Unprecedented Levant offshore exploration & infrastructure development:

 A need for basic understanding  Global technical challenges  Environmental concerns

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Two collaborative ROV cruises of E/V Nautilus investigated, in 2010 and 2012 the deep Mediterranean offshore of Israel at water depths of 500-1700 m

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Bathymetry of the deep offshore of Israel Hall, 1980

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Bathymetry of the deep offshore of Israel Hall and Sade, 2008

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Bathymetry of the deep offshore of Israel IBS & IOLR 2012

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SLIDE 7

Bathymetry of the deep offshore of Israel 3D seismics + Tamar Site Survey

The eastern turbidite channel

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SLIDE 8

3D seismic Multibeam The turbidite channel is truncated by salt related faulting

The western edge of Palmahim Disturbance

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SLIDE 9

ROV surveying of the channel near Tamar

Noble Energy

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3D seismic Multibeam The southern fault of Palmahim Disturbance

The western edge of Palmahim Disturbance

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SLIDE 11

Garfunkel et al., 1979 Hampton et al. (1996)

The Palmahim Disturbance is an apparently-active rotational slide

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150 250 200 300 350

Garfunkel et al., 1979

Ongoing activity of the Palmahim Disturbance

1 2 Horizontal scale [km]

Two Way Time [msec] 100 140 120 160 180 200 Approximate Depth [m]

Joint CU-BGU-IOLR-UH cruise, May 2011

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A preliminary depth migrated section through the Palmahim Disturbance Yaniv Marig MSC

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An opportunity to investigate the Messinian salt

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Deformation zones within the continental margin of Israel Murad Safadi MSC

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Wells and

Seafloor stability and submarine slides pose major geohazards to infrastructure development

Frey-Martinez et al., 2005

~5 km

Noa pipeline 2012

Yam W 01 Yam W 02 Or 01 Noa 01 Noa S 01 Or S 01 Andromeda E 01 Mari-B Pinnacles

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SLIDE 17

Shallow gas accumulations and seepage at the toe of Palmahim Disturbance

Large scale pockmarks Pockmark Bright spot reflection

Garfunkel et al., 1979

~5 km 1 km N

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SLIDE 18

Active seafloor gas seeps at the toe of Palmahim Disturbance

Water depth ~1100m

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y = 0.58x + 0.42 R2 = 0.93 1 2 3 4 5 6 7 2 4 6 8 10

Silicate (mmol/L) Nitrate (mmol/L)

N:Si = 16:15 (Brzezinski, 1985)

Ni:Si = 16:15 (Brzezinski, 1985)

At the seafloor Above the seafloor

Jack Silverman & Niv David

Si (μmol/L) Ni (μmol/L)

Gilad Antler & Orit Sivan Preliminary analysis of push- core and Niskin interstitial, surface and above-seafloor water reveal:

  • high concentrations of methane
  • Carbon isotopic values suggesting

a biogenic origin

  • oxygen depletion in near surface

water

  • Si enrichment at the seafloor
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SLIDE 20

Hard rock reefs at water depths of 600-800 m host an oasis of biodiversity, primarily Antipatharian and Grogonian corals

Water depth 700m Water depth 780m

Garfunkel et al., 1979

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Oxygen an Carbon isotopes in Pal 2 NA009 49D AHDFA

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  • 36
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5.0 5.2 5.4 5.6 5.8 6.0 d18O (permil vrs PDB) d13C (permil vrs PDB)

Preliminary analysis of a tubular rock sample suggests a methanogenic origin

Sulphide – pyrite in SEM scan attesting bacterial reduction Oxygen and Carbon isotopes attesting oxidation of CH4 Baruch Spiro

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Akko Haifa

Active methane seepage in seafloor pockmarks offshore Akko

Water depth 1100m

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Other possible evidence of methane seepage along the edges of the Levant basin still need to be investigated

Offshore Israel Eratosthenes Sea Mount (Mayer et al., 2011)

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SLIDE 24

Methane seepage is now found in a rim around much of the Levant basin

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Several apparent gas shows within the post Messinian section

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Gas seeps

Hydrate stability models

  • vs. seismic reflectivity

A depositional system? 1 2 3

1. 2. 3. So what about hydrates?

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Biology Geology & Geophysics Maritime Law Political Sciences Economics Environmental Resources Management Archaeology & History Remote sensing Physical & chemical Oceanography Engineering & Technology

Pulling together interdisciplinary expertise and modern research infrastructure at the national level.

Isr Israe ael l Cen Center ter of

  • f Medite

Mediterran anea ean n Se Sea a Res esea earch

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SLIDE 28

Thank you

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Shallow gas on the Mediterranean shelf offshore Israel

High amplitude reflections in sparker profiles

Neev et al., 1966 Golan, 2006

The extent of the gas layer

  • ffshore Israel

Golan, 2006:

  • Analysis of cores samples indicate the presence of

Methane, probably of biogenic origin. Schattner et al., 2012

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48 52 56 64 68 60 72 36 39 42 48 51 45 54 80 160 240 320 400 480 560 720 640 800

Pock mark? Seismic ‘bright spot’ Scattered high amplitude reflectivity Stretched reflections

A gas bearing stretch is present within the layered sediments

Northern Bay of Haifa Survey Line-20

Two-way-time [msec] Approximate depth [m] Approximate distance along profile [m]

Characterizing shallow gas on Haifa Bay reflection profiles

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84 68 60 76 80 160 240 320 400

Evaluating gas content Northern Bay of Haifa Survey - Line-20

Two-way-time [msec] 66 54 42 60 48 80 160 240 320 400 Approximate depth [m] Approximate distance along profile [m]

  • Examining the specular reflections

by removal of the diffuse reflectivity (low-pass filter + lateral mix) The high amplitude reflections are actually concentrated in a ~6 m wide gas-bearing section

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84 68 60 76 80 160 240 320 400

Evaluating gas content Northern Bay of Haifa Survey - Line-20

Two-way-time [msec] 66 54 42 60 48 80 160 240 320 400 Approximate depth [m] Approximate distance along profile [m]

  • Examining the specular reflections

by removal of the diffuse reflectivity (low-pass filter + lateral mix)

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Migration of gas in granular sediments

Best et al. (2004)

Bubble tracks in a. Silty sands b. clay Invasion by: a. Capillary pressure b. Fracture opening

Jain & Juanes (2009)

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40 60 80 100 120

Corrected time [msec]

~1 km

Haifa Bay A gas front within the shallow sediments

Surface-A Surface-A

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Whiticar (2002)

The bubbles dissolve as the ascend until they disappear and the methane is consumed

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Picks of Top Gas w/r to Surface-A overlaid on a map of Surface-A w/r to the seafloor

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Picks of Top Gas w/r to the seafloor overlaid

  • n a map of Surface-A w/r to the seafloor

A zoom on the highly variable southwest corner

  • f the study area