GasGas HydratesHydratesHistoryHistoryWhy the interest?Why the interest?Chemical AspectsChemical AspectsBiologyBiologyGeologyGeologyUtilization as a Fuel Source and Future DevelopmentUtilization as a Fuel Source and Future Development

History Discovered in late 19th century Discovered in late 19th century

in Siberian permafrostin Siberian permafrost

Known to form pipeline Known to form pipeline blockages for yearsblockages for years

““Rediscovered” as oil Rediscovered” as oil exploration moved offshore in exploration moved offshore in early 1970’searly 1970’s

•Why the sudden interest?

• The fuel of the next century?

• Worldwide reserves estimated to be 400-500 million trillion cubic feet(tcf)

• 5000 tcf of known natural gas reserves worldwide

Map of in-situ hydrate locationsMap of in-situ hydrate locations

• USA has gas hydrate reserves estimated between 112000 tcf and 676000 tcf

• USA has 1400 tcf of natural gas reserves• USA uses 25-30 tcf/yr of natural gas

Carbon reserves vs gas hydratesCarbon reserves vs gas hydrates

•Chemical Aspects Chemical Aspects of Gas Hydratesof Gas Hydrates

• Ice-like crystaline mineralIce-like crystaline mineral

• 1 cubic meter of gas hydrate (90% 1 cubic meter of gas hydrate (90% site occupied) = 163 msite occupied) = 163 m33 of gas + .87 of gas + .87 mm33

• Clathrates or Clathrate HydratesClathrates or Clathrate Hydrates

• Three Structure Types: I, II, HThree Structure Types: I, II, H

• Structure type determines gas typeStructure type determines gas type

• Scientist don’t fully understand the Scientist don’t fully understand the physics of gas hydrate formation physics of gas hydrate formation

• Structure I Gas Hydrate Structure I Gas Hydrate Crystal - Cubic LatticeCrystal - Cubic Lattice

• Can hold only small Can hold only small molecules (5.2 angstroms molecules (5.2 angstroms or less) such as or less) such as ethane(Cethane(C22HH66) and ) and methane(CHmethane(CH44))

• Biogenic in originBiogenic in origin

• Structure II Gas Structure II Gas Hydrate Crystal-Hydrate Crystal-Diamond LatticeDiamond Lattice

• May contain larger May contain larger molecules (5.9-6.9 molecules (5.9-6.9 angstroms) such as angstroms) such as propane(Cpropane(C33HH88) or ) or isobutane(Cisobutane(C44HH1010))

• Thermogenic in originThermogenic in origin

• Structure H Gas Structure H Gas Hydrate Crystal - Hydrate Crystal - Hexagonal LatticeHexagonal Lattice

• Rare Rare

• Able to hold much Able to hold much larger molecules such larger molecules such as iso-pentaneas iso-pentane

A Little ChemistryA Little Chemistry

• Environmental Environmental ConcernsConcerns

• Formation of Formation of hydrates from gas hydrates from gas vent flumesvent flumes

• Contribution to Contribution to greenhouse effect?greenhouse effect?

Hydrates Support Dense Hydrates Support Dense Biological CommunitiesBiological Communities

Bacterial matsBacterial mats Tube wormsTube worms MusselsMussels Shrimp Shrimp CrabsCrabs FishFish EelsEels IsopodsIsopods Polychaetes (the newly discovered “Ice Worm”)Polychaetes (the newly discovered “Ice Worm”)

Sediment Failure

http://www.earthinstitute.columbia.edu/news/aboutStory/pdf/28-407.pdf

Eruptions

Hydrate Ridge

Storegga Slides

LOCATION OF GAS HYDRATES

Using seismic-reflection

• Seismic-reflection Profile

• Side Scan Sonar

Coring

http://www.ngdc.noaa.gov/mgg/bathymetry/relief.html

using seismic-reflection profiles

Bottom Simulating Reflection (BSRs)

http://woodshole.er.usgs.gov/project-pages/hydrates/hydrate.htm

Side-Scan Sonar

http://gulftour.tamu.edu/cruise_background2.html

Coring

http://www.hydrate.org/about/geology.cfm#Where%20Found

The FutureThe Future USA has suggested in 2000 that $47.5 million be USA has suggested in 2000 that $47.5 million be

used to explore the option of gas hydrates over used to explore the option of gas hydrates over a five year period.a five year period.

Japan has enormous offshore deposits and Japan has enormous offshore deposits and plans to have production on line by 2015 ($60 plans to have production on line by 2015 ($60 million on research)million on research)

India is also looking into converting its offshore India is also looking into converting its offshore deposits ($50 million on research)deposits ($50 million on research)

Germany, France, and Australia also starting to Germany, France, and Australia also starting to fund researchfund research

Challenges of Hydrate Challenges of Hydrate Utilization as a Fuel SourceUtilization as a Fuel Source

Hydrates decompose releasing hydrocarbons as a gas Hydrates decompose releasing hydrocarbons as a gas when removed from low temp/high pressure environmentwhen removed from low temp/high pressure environment

High costs of long pipelines across unstable continental High costs of long pipelines across unstable continental slopesslopes

Pipelines in deep cold water become plugged with Pipelines in deep cold water become plugged with hydrates during transporthydrates during transport

Damage to sensitive chemosynthetic communitiesDamage to sensitive chemosynthetic communities

Potential New Approaches Potential New Approaches to Transport Hydratesto Transport Hydrates

Pelletize the hydratePelletize the hydrate

Inflate large bladder-like blimps with hydrate and Inflate large bladder-like blimps with hydrate and tow to shallower water to allow a slow controlled tow to shallower water to allow a slow controlled decompositiondecomposition

Additives to stabilize hydrates at lower pressures Additives to stabilize hydrates at lower pressures and higher temperature environments for safer and higher temperature environments for safer transport by shipstransport by ships

Advantages of Hydrates as a Advantages of Hydrates as a FuelFuel

Denser source of hydrocarbons than conventional sourcesDenser source of hydrocarbons than conventional sources

Amount of conventional fossil fuels will decline in next centuryAmount of conventional fossil fuels will decline in next century

Redirect/dispose of greenhouse methane away from the Redirect/dispose of greenhouse methane away from the atmosphereatmosphere

Cleaner fuel source than oil, coal, and oil shaleCleaner fuel source than oil, coal, and oil shale

Abundant supplies in deep sea and permafrostAbundant supplies in deep sea and permafrost