Methane hydrates and sea floor processes and emissions Jrgen - - PowerPoint PPT Presentation

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Methane hydrates and sea floor processes and emissions Jrgen - - PowerPoint PPT Presentation

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Methane hydrates and sea floor processes and emissions Jrgen Mienert 30.October 2013 Wood and Jung, 2008 GLOBAL ASSESSMENTS Global resource estimates decrease Global Resource Estimates - GIP V Variety of Hydrate Forms in Nature

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Methane hydrates and sea floor processes and emissions

Jürgen Mienert 30.October 2013

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GLOBAL ASSESSMENTS

Wood and Jung, 2008

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Global “Resource” Estimates - GIP

Global resource estimates decrease

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V

Variety of Hydrate Forms in Nature

Pore-filling in coarse grained sand (Canada) Massive mounds on Sea-floor (Gulf of Mexico) Thin veins in muds (Korea) Massive lenses and nodules in muds (India) Pore-filling in fine-grained marine sands (Japan)

Fujii et al, 2009 Park et al, 2005 Dallimore and Collett, 2005 Collett et al, 2008

Disseminated in muds (China)

50,000 tcf 100,000 tcf 700,000 tcf 4,000,000 tcf

Texas A&M and Scripps Institute

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GH Energy Resource Assessment

USGS (Collett et al., 2008)

  • Technically-Recoverables!
  • Discrete Accumulations

– Used the USGS methodology that is used for “conventional” reservoirs – Three AUs; with size range and accumulations numbers for each

  • 85 tcf mean estimate

– Existing Technology – High ultimate tech recoverability

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Nankai Trough

Takano et al., 2007 Fujii et al., 2008

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Nankai Trough

  • Geologic GIP Assessment
  • A, H, Φ, Sgh from log and

seismic data

  • Area = 5,000 km2 (10% of

total prospective area)

  • 20 tcf in 10 high-Sgh zones
  • 40 tcf in full section
  • % in sand-“anomalies”

– Nankai Trough = 50% – Gulf of Mexico = 30% – Alaska N. Slope = 100%

Saeki, et al., 2008

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NW Svalbard

  • Vestnesa Ridge is a large

sediment drift west of Svalbard.

  • Situated on relatively young

Oceanic crust (< 20Ma).

  • Sediment thickness

increases west to east, where it is about 6-8 km.

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Vestnesa Ridge

  • Pockmarks at the top
  • f the ridge.
  • Active venting system.
  • Faults at seafloor

indicate recent tectonic activity.

Hustoft et al., 2009

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Vestnesa Ridge

Hustoft et al., 2009 Hustoft et al., 2009

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Active methane venting from the Vestnesa Ridge

Gas bubble plumes above pockmarks at Vestnesa in 2010 and 2012

Smith et al., submitted.

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Bottom simulating reflector (BSR) indicates base of the gas hydrate stability zone

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Vestnesa gas-hydrated ridge

  • BSR widespread covering an

area of > 3000 km2.

  • Recognize 3 different BSR

zones with differing controls (Vestnesa Ridge, continental slope, Molløy Transform, Knipovich Ridge).

  • Covers Vestnesa Ridge crest

continuously.

  • Often absent at the foot of the

Vestnesa Ridge.

  • Significant BSR occurrence at
  • r across the Molloy Transform

Fault.

  • BSRs north and south of the

Vestnesa Ridge area.

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Gas release at massive Hinlopen slide in the Arctic?

Variable conditions in the area:

  • Geothermal gradient
  • GHSZ
  • Free gas area
  • Biogenic gas
  • Thermogenic gas
  • High Temperature
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