1. SEMINAR
TOPIC: GAS HYDRATES
GUIDED & COORDINATED BY: SUBMITTED BY:
MR. SAIF V KHASIM AJMAL ROSHAN.P
ASST. PROFESSOR ME 1 , 13
MECHANICAL DEPT MECHANICAL DEPT
2. IMPORTANCE OF ENERGY
Energy is fundamental to the quality
of our lives.
Nowadays, we are totally dependent
on an abundant and uninterrupted
supply of energy for living and working.
It is a key ingredient in all sectors of modern
economies.
3.
4. DIFFERENT PHASES OF PETROLEUM
• COAL
• OIL
• SHALE GAS
• OIL SHALE
• OIL SANDS
• METHANE HYDRATES
PETROLEUM DESCRIBES ORGANICALLY FORMED C-H CHAINS
- RELEASES ENERGY WHEN IT REACTS WITH OXYGEN THROUGH BURNING
5. Coal and gas
swampy land environment…
Burial of Plants Decomposition without oxygen Coal
mining along in-situ coal seams & Gas expelled
6. Oil and gas
• Burial of plankton Maturation with heat and
pressure Migration of oil/gas Trapping in
reservoir
• This depends on; 1. Plankton type
2. Burial/Maturation extent
7. • Plankton are microscopic organisms that live in
watery environments.
• If the buried Plankton is lignin rich (material
present in plant cell walls) then it matures
directly to Gas
• Otherwise it is probably lipid rich and will mature
initially to form Oil
What if… there is no migration ?
OPTION 1: petroleum is ‘trapped’ in the source
rock due to low permeability leading to…
Fracking to release Shale Gas
8. • OPTION 2: the source rock has not been
buried/heated enough for migration of the
petroleum leading to…
Heating to release Oil Shale
• What if… the oil has migrated BUT bacteria exists
in the reservoir?
Bacteria in reservoirs live off (eat) the light ‘short-
chained’ hydrocarbons leaving only heavy oil which
is described as Oil Sands/Tar Sands.
• Bacteria is more likely to exist in shallower and
cooler reservoirs that are oxygenated e.g. by
contact with surface waters
9. OUTLINE OF PRESENTATION
1. WHAT ARE GAS HYDRATES?
2. OCCURRENCE OF GAS HYDRATES
3. ARE GAS HYDRATES SUSCEPTIBLE TO
CLIMATE CHANGES?
4. GAS HYDRATE PRODUCTION METHOD
10. A fuel to ignite worlds energy crisis it
looks like ice – but put a flame to it
and it goes blaze
11. WHAT ARE GAS HYDRATES
• Crystalline Solids composed of H₂O and gas; the
gas molecules (guests); are trapped in water cavities
(host) that are composed of hydrogen- bonded water
molecules. Typical natural gas molecules include
methane, ethane, propane and CO₂
- One volume of methane hydrate typically contains about
160 volumes of methane gas
• occur abundantly in nature
Around 6.4 trillion (6.4×1012) tonnes of methane is trapped in deposits of methane
clathrate on the deep ocean floor.
• Are stable at low temperature and high pressure
12. • TYPES OF GAS HYDRATES:-
• Hydrates are basically of three types, Type I, Type II & Type H. Each has different
No. of water and gas molecules.
• The ratio of water molecules to gas molecules is called hydrate number.
• The amount of gas actually contained is called the "Degree of Filling".
13. • TYPE I:-
o § It is usually smaller molecules.
o § Type I hydrate formers include
1) Methane
2) Ethane
3) Carbon dioxide
• TYPE II:-
o § It is usually larger molecules.
o § Type II hydrate formers include
1) Propane
2) Isobutane
3) Nitrogen
• TYPE H :-
o § Type H hydrates are formed by larger molecules but only in the presence
of a smaller molecules, such as methane.
o § Type H hydrate formers include
1) 2-Methyl butane
2) Methyl cyclo pentane
14. CONDITION OF FORMATION:-
Hydrates are formed when -
• A sufficient amount of water is present
• Gas hydrates exists where the water depths
exceed 300 to 500 meters.
• The right combination of temp. & Pressure.
• The hydrate former gases are present.
15. Where and How Does Gas Hydrate
Form?
Gas hydrate is stable in the underlying sediments to a depth of about 225 m below
the seafloor. Also gas hydrate is stable from about 200 to 600 m within the
permafrost and from 600 m to ~1100 m beneath the permafrost.
20. DEPRESSURIZATION
•MOST PRACTICAL AND COST EFFECTIVE METHOD
•WELLBORE PRODUCTION LEAD TO FLUID FLOW & PRESSURE
•HYDRATES DESTABILIZES AND GENERATED GAS FLOW TO
WELL
•GAS CAN BE COLLECTED
21. THERMAL STIMULATION
• Main objective is to temperature within the
reservoir
• Destabilizes the gas hydrate
• Thermal heating alone is inefficient and expensive
means of producing gas hydrates for long term
• Limitation- 75% heat applied will be wasted by non
hydrate strata (thief zone).
• - horizon should be having high porosity
This limitation make it expensive
23. CO₂ REPLACEMENT/INHIBITOR INJECTION
• The ability of CO₂ molecule to displace methane molecule in the
hydrate cage.
• Without the hydrate cage being broken or melted.
• Certain chemicals and alcohols have capability to shift the
pressure and temperature needed for hydrates.
• Shift hydrate equilibria and lower the hydrate formation temp.
Eg: methanol, MEG, DEG.
• Enable hydrate dissociation and methane release.
24. Climate change
• Methane from hydrate reservoir might significantly modify
the global green house, because methane is ~20 times as
effective as CO₂.
• More methane exists in the present day atmosphere.
• Because hydrate breakdown, causing release of methane to
the atmosphere, can be related to pressure caused by glacial
sea level fluctuation.
• Gas hydrate may play a role inn controlling long term global
climate change.
25. CONCLUSION
• Pure methane hydrate produces 164 volumes of gas at STP
• The potential amount of methane in natural gas hydrate is
enormous, with current estimates converging around about 10
terra tons (10^19g) of methane carbon.
• When methane hydrate production technology is established
and commercialization is realized. It is expected to become a
new domestic energy source that will significantly contribute
to securing stable supplies of energy in world.
• Potentially this resource could be the back bone for the world’s
energy sector during 21st century
