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gas hydrates
- 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 Energyis 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.
- 4. DIFFERENT PHASES OFPETROLEUM • 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 swampyland 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 aremicroscopic 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 toignite worlds energy crisis it looks like ice – but put a flame to it and it goes blaze
- 11. WHAT ARE GASHYDRATES • 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 OFGAS 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:- Hydratesare 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 HowDoes 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.
- 16. Global Occurrence &Distribution of Natural Gas Hydrates
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- 19. PRODUCTION • DEPRESSURIZATION • THERMALSTIMULATION • CO₂ REPLACEMENT OR INHIBITOR INJECTION
- 20. DEPRESSURIZATION •MOST PRACTICAL ANDCOST EFFECTIVE METHOD •WELLBORE PRODUCTION LEAD TO FLUID FLOW & PRESSURE •HYDRATES DESTABILIZES AND GENERATED GAS FLOW TO WELL •GAS CAN BE COLLECTED
- 21. THERMAL STIMULATION • Mainobjective 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
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- 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 • Methanefrom 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 methanehydrate 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