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Methane Hydrates as Potential Energy ResourceProject Report- Natural Gas TPG 4140

Niloofar Aslankhani khameneh

Samira Bahmani

Waqas Mushtaq

TrondheimNovember 2012

Norwegian University of Science and Technology,

Department of Petroleum and Applied Geophysics

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Methane Hydrates as Potential Energy Resource 2012

II

Summary

Methane hydrate science has advanced steadily over the past decade. The commercial scale

production of natural gas from methane hydrate deposits is growing more viable at each step. For

this reason, experimental modeling, and field based studies are underway to advance the

understanding of this future potential resource.

When water and gas are combined under low temperatures and high pressures, the result would

be a frozen lattice like substance called methane hydrate. The huge amounts of these hydrates

underlie our oceans and polar permafrost.

Their wide distribution throughout the world makes them more substantial for future energy

resource. Some deposits are close to the ocean floor and at water depths as shallow as 150 m.

These deposits can be 300 to 600 m thick and cover large horizontal areas. By some estimates,

the energy locked up in methane hydrate deposits is more than twice the global reserves of all

conventional gas, oil, and coal deposits combined.

A number of methods have been applied to extract methane from the hydrates. But there are also

some environmental global concerns related to their production. These economic and

environmental issues that relate to gas hydrates are being resolved. Research studies are going onto find the most efficient and cost effective method for recovery of methane from hydrates. So,

they are being considered as potential energy resource for future.

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III

Table of Contents

Summary ................................................................................................................................................... II

Abbreviations ............................................................................................................................................ V

1. Introduction ...................................................................................................................................... 1

2. Early studies of methane hydrate ......................................................................................................... 2

3. Methane hydrate reservoirs ................................................................................................................. 3

3.1 Arctic hydrates ................................................................................................................................ 3

3.2 Marine hydrates .............................................................................................................................. 4

4. Methane hydrate formation and stability zone .................................................................................... 5

5. Methods for the extraction of methane from methane hydrate ......................................................... 8

5.1 Thermal injection ............................................................................................................................ 9

5.2 Depressurization ........................................................................................................................... 10

5.3 Inhibitor injection .......................................................................................................................... 11

6. Methane Hydrates as Potential Source .............................................................................................. 14

6.1 Methane hydrate pyramid ............................................................................................................. 14

6.2 Wide geographical distribution..................................................................................................... 15

6.3 Their occurrence at shallow depths .............................................................................................. 16

6.4 Higher energy potential and energy demands ............................................................................. 17

6.5 Environment friendly .................................................................................................................... 17

7. Challenges ........................................................................................................................................... 19

7.1 Global climate changes ................................................................................................................. 19

7.2 Energy Resources .......................................................................................................................... 20

7.3 Sedimentary instability and failure ............................................................................................... 22

8. Economic aspects ................................................................................................................................ 23

9. Discussion ........................................................................................................................................... 24

10. Conclusion ........................................................................................................................................ 25

11. References ........................................................................................................................................ 26

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IV

List of Figures

Figure 1: Distribution of methane hydrate reservoirs around the world ...................................................................... 3

Figure 2: The arctic showing continental shelf, permafrost, sea floor methane hydrate, and 2011 arctic sea ice

minimum (from NSIDC) ......................................................................................................................................... 4

Figure 3: Sites where natural gas hydrate has been recovered or is inferred ............................................................... 4

Figure 4: Methane hydrate crystalline structure ........................................................................................................... 5

Figure 5: methane hydrate film formed on the free gas-water surface(Makogon, 1960) ............................................ 5

Figure 6: Hydrate phase diagram(Kristian Sandengen, Statoil, October 2012) ............................................................. 6

Figure 7: Stability zone of methane hydrates ................................................................................................................ 6

Figure 8: Methane hydrate ............................................................................................................................................ 7

Figure 9: Ice-like solid which burns ................................................................................................................................ 7

Figure 10: Gas production by thermal stimulation(heat injection) process .................................................................. 9

Figure 11: Gas production by depressurization process .............................................................................................. 10

Figure 12: Gas production by chemical inhibitor injection process............................................................................. 12

Figure 13: A schematic figure of a well ................................................................................................................ 13

Figure 14: Injection of into the well (the blue stream) ......................................................................................... 13

Figure 15: the release of methane through the pipes (the red stream) ...................................................................... 13

Figure 16: the methane hydrate resource pyramid.(The Energy lab,2011) ................................................................ 14

Figure 17: location of sampled and inferred gas hydrate occurrences worldwide.(The Energy Lab, 2011) ............... 16

Figure 18: distribution of organic carbon on earth(excluding dispersed carbon in rocks and sediments) ................. 17

Figure 19: increasing demand of gas in future(Patrick Hendriks, Gassco, October 31, 2012)) ................................... 18

Figure 20: location of Mallik well in Canada.(The Energy Lab, 2011) .......................................................................... 21

Figure 21: Natural Gas flare at Mallik site.(The Energy Lab, 2011) ............................................................................. 21

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V

Abbreviations

LTPM:Late Paleocene Thermal Maximum

GHSZ: Gas Hydrate Stability Zone

BSR:Bottom Simulating Reflector

GHD:Gas Hydrate Dissociation

BTU:British Thermal Unit

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1

Introduction

This report is a part of our course Natural Gas. The scope of this course is to make the students

realize the importance, production and issues related to natural gas. Discovery of methanehydrates over past decades is assumed to be the biggest achievement. Scientists and researchers

are making their efforts to produce these hydrates commercially and making them economically

feasible. Reliance on energy resources and decreasing amount of other fossil fuels urge scientists

and researchers to look for new resources. Energy resources are dwindling day by day due to

massive use in our daily life. As the amount of available petroleum decreases, the need for

alternate technologies to produce liquid fuels that could potentially help protracts the liquid fuels

and alleviate the future effects of the shortage of transportation fuels.

Natural gas is considered as one of the main energy resources in the world. It is mainly consist of

methane (CH4), which is normally found with the mixture of other gases like carbon dioxide,

nitrogen, sulfur dioxide and many others. Extracting methane from the gas hydrates has taken the

attention of many researchers and energy experts over the past decade. Their wide distribution

and shallow depth availability made them more striking and imperative.

Gas hydrates are complex mixture of methane and water in the form of ice. They are usually

found in the areas with high pressure and low temperature. In Methane hydrates, molecules of

natural gas are trapped in an ice like cage of water molecules represents a potentially vast

methane resource for the world. Recent discoveries of methane hydrate in arctic and deep water

marine environments have highlighted the need for a better understanding of this substance as a

natural storehouse of carbon and a potential energy resource.

Numerous ways of extracting methane from hydrates are in use. Scientists came up with the

success in many cases and they have very optimistic approach to prove them as potential

resource. The issues related to exploitation of these hydrates cannot be neglected. So, research

works are underway to resolve them. Extensive research and development in this field is being

done by many countries which show the significance of these hydrates.

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2. Early Studies of Methane Hydrate

The very first scientific research into the nature of methane hydrate goes back to the early 1800s,

when scientists first created synthetic hydrate in a physical chemistry laboratory. For decades

after that, hydrate was created and tested in laboratory experiments and at that time it was not

expected to be encountered in the natural world.

However in the 1930s, hydrate was observed forming in natural gas pipelines, in some cases

blocking the flow of gas. This brought about a new phase of scientific work, focused on

developing techniques to inhibit gas hydrate formation in pipelines. But methane hydrate was

first discovered in the natural world in the 1960s, in subsurface sediments of the Messoyahka gas

field of the Western Siberian basin. Then in the 1970s, hydrate was observed in well samples

from the North Slope of Alaska, and in seafloor sediments collected from the bottom of the

Black Sea. These initial findings were followed by a major hydrate discovery in the early 1980s,

when the Deep Sea Drilling Program recovered hydrate bearing cores, including a 1 meter

sample of nearly pure hydrate, from sediments off the coast of Guatemala. (The energy lab,

2011)

These discoveries led to the realization that methane hydrate was not just a laboratory curiosity

or industrial nuisance. Methane hydrate began to be viewed as a potentially widespread, naturalreservoir of methane.

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3. Methane Hydrate Reservoirs

There are two different reservoirs for gas hydrate which are categorized as Arctic and marine

hydrates. This means that gas hydrates can be found both within and under permafrost in arctic

regions and also within a few hundred meters of the seafloor on continental slopes and in deep

sees and lakes. The figure 1 is showing the methane hydrate distribution throughout the world.

Such a wide spread make these hydrates more appealing and to be considered as potential

resource.

Figure 1: Distribution of methane hydrate reservoirs around the world

3.1 Arctic Hydrates

The arctic hydrates have the potential to become economically permanent sources of natural gas.

The best documented Alaska accumulations are in the Prudhoe Bay- Kuparuk river area, which

contains about 30 trillion standard cubic feet of natural gas, about twice the volume of

conventional gas found in the Prudhoe Bay field (Ayhan Demirbas, 2010). Other reservoirs exist

elsewhere on the north slope of Alaska, in northern Canada and in Siberia. Some important arctic

hydrate accumulations have good porosity and good gas saturation, and are predominantly found

in coarse sands that have high intrinsic permeability.

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Figure 2: The arctic showing continental shelf, permafrost, sea floor methane hydrate,and 2011 arctic sea ice minimum (from NSIDC)

3.2 Marine Hydrates

Subsea gas hydrates have been thought to contain the excellent hydrates to be found in the

geosphere. Moreover, they are to be found much closer to markets than are arctic hydrates.

Promising accumulations have been thought to exist off the east, west and Gulf coasts of the US,

as well as offshore Japan, India, China and other important energy consuming nations. (Ayhan

Demirbas, 2010). Also the Gulf of Mexico with its abundant gas seeps in deep water is probably

the most promising marine gas hydrate province in US waters.

Figure 3: Sites where natural gas hydrate has been recovered or is inferred

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4. Methane Hydrate Formation and Stability Zone

Gas hydrates are formed from mixtures of water and light natural gases such as methane, carbon

dioxide, ethane, propane and butane. Since, methane hydrates are made up of methane which is

the dominant component among other hydrocarbon gases in the sediments. Methane is a

colorless, odorless and combustible gas which is produced by bacterial decomposition of plants

and animal matters. Figure 4 is showing that gas hydrates are ice-like crystalline solids

comprised of hydrogen bonded water lattice with entrapped guest molecules of gas.

Figure 4: Methane hydrate crystalline structure Figure 5: methane hydrate film formed on the free gas-water

surface(Makogon, 1960)

There is actually no chemical bond involved between the water molecules and the gas molecules

other than Van der waals forces. The important point here is that, the presence of guest

molecules inside the ice crystals makes the structure of the entire lattice more stable (Rayner-

Canham, 2006). In fact the presence of guest molecules stabilizes the structure enough to have

the effect of raising the melting point of the ice to several degrees above 0 C.

According to the U.S. Geological Survey, the organic carbon content of methane hydrates

worldwide is estimated at 104 Giga tons, roughly twice the amount contained in all fossil fuels

combined. Generally methane hydrates are formed under specific conditions of low temperature

(around 5c) and high pressure (27.6 bars and correspondent to the depth of more than 500

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meters). They should be accumulated with organic remains, from which bacteria have generated

methane. These sediment rapidly collect and protect the remains from oxidation.

The stability curve in figure 6 shows that methane hydrate is stable at almost 0.1 MPa or 1 bar if

temperatures are low enough and that it is stable far above the melting point of water ice if

pressures are high enough. And more specific information on the stability zone can be seen in

figure 7, where the horizontal axis shows temperature, increasing from left to right, and the

vertical axis shows depth of burial, increasing from top to bottom.

Due to increase in fluid pressure with depth below the surface of the earth or the ocean, depth

serves as a proxy for fluid pressure in hydrate phase diagrams. The curved line between the blue

and yellow areas is the methane hydrate phase boundary. To the right of this phase envelop,

temperatures are too high, and pressures are too low for methane hydrate to form, so methane

can only be present as a gas. Below this boundary, solid methane hydrate is able to form and

remain stable, because temperatures are sufficiently low, and fluid pressures are sufficiently high

to maintain the solid phase.(The energy lab, 2011).

Figure 6: Hydrate phase diagram(Kristian Sandengen, Statoil, October 2012)Figure 7: Stability zone of methane hydrates

Moreover gas hydrate has a very high energy yield. One cubic meter of methane extracted from

hydrate expands into 164 cubic meter of regular natural gas. If you take a piece of methane

hydrate and touch a lighted match to it, the sample will burn with a reddish flame. And if that is

the case, it could be used to heat homes, fuel cars and generally power energy hungry nations

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such as Japan, the United States, India and China. Recent data suggest that just 1 percent of

earth's methane hydrate deposits could yield enough natural gas to meet America's energy needs

for 170,000 years. (Alex Stone,2004).

Figure 8: Methane hydrateFigure 9: Ice-like solid which burns

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5. Methods for the Extraction of Methane from Methane Hydrate

Methane clathrate beds are very extensive, and there may be large volumes of proven trapped gas

reserves in them. A major problem is that the hydrate density of any particular location is usually

not high (Ruppel, 2007). While the direct gathering of solid methane hydrates would be

impractical because of low unit per volume concentrations. Several techniques might be

requiring for the extraction of methane from hydrate beds. Until now most of the extraction

techniques of methane from methane hydrate have been limited to the laboratory tests and

experiments. But with the research budget growing on the development of different methods,

methane hydrate has proven as an important part of potential source of energy for the future.

Most natural gas is produced from conventional gas accumulations by drilling a well into the

reservoir rock, casing the well with pipe, perforating the pipe to allow the gas to flow into the

wellbore, placing a string of tubing inside the casing and then extracting the gas up the tubing.

Natural gas flows from the reservoir rock into the well and up the tubing as long as the pressure

at the bottom of the well is lower than the pressure in the reservoir. In some cases, natural gas

flows freely up the tubing without the aid of a pumping system, because of high pressure in the

reservoir. Production of methane from hydrate deposits in sandstone or sandy reservoirs can be

approached in a similar manner. As pressure in the well bore is reduced, free water in the

formation moves toward the well, causing a region of reduced pressure to spread through the

formation. Reduced pressure causes the hydrate to dissociate and release methane. Further

removal of water and gas causes more reduction in pressure and dissociation then finally

methane production.

There are numerous methods for extracting methane and as it has been mentioned earlier they all

rely on creating a slow controlled dissociation process. They involve the alteration of the thermo-

dynamic conditions in the hydrate stability zone, which will thus increase the temperature and

reduce the pressure. The application of this process will cause the icy crystals to melt or

otherwise change form and release the entrapped natural gas molecules. But before all these, any

possible extraction site will have to be extensively well studied, and extraction techniques would

have to be proven safe, efficient, cost effective, and environmentally friendly. Once these criteria

are met, there are three foremost methods by which hydrate gases may be collected.

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9

5.1 Thermal Injection

Heat will be introduced into the hydrate formation to raise the temperature and promote

dissociation. It can be done by injecting the relatively hot water or steam into a subsea gas

hydrate layer which would partially melt the hydrate beds in ocean sediments or in permafrost

regions. The gas will then flow to the bore hole where it can be ascend through the pipe up to the

surface. This process has a favorable net energy balance as the heat energy required for

dissociation is about 6% of the energy contained in free gas (Ayhan Demirbas, 2010). An

advantage of this method is that it is simple and would be conceivably easy to do. However, the

major disadvantage is that heating the fluids to pump underground would be costly and might not

reach deeper hydrate sediments (Ruppel, 2007). Also the endothermic nature of gas hydrate

dissociation acts as a challenge to thermal stimulation, the cooling associated with dissociation(and, in some cases, gas expansion) will partially offset artificial warming of the formation. It

means that more heat must be introduced to drive continued dissociation and prevent formation

of new gas hydrate.

There are following four simple steps which are involved in methane hydrate dissociation

process by hot water injection;

1. Displacement of free methane gas due to water injection

2. Additional methane hydrate formation at downstream zone because of migration of

dissociated gas and water

3. Actual methane hydrate dissociation

4. Completion of dissociation

Figure 10: Gas production by thermal stimulation(heat injection) process

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5.2 Depressurization

The second method involves depressurization of hydrates in sediment beds. In this process the

hydrates are exposed to a low pressure environment where they are unstable and dissociate to

methane and water. This would be done by drilling deep into clathrate beds where methane can

exist in the free gas stage before being converted to hydrates. The heat energy for the process

comes from the earthsinterior.

Depressurization could be the easiest way to collect hydrate gases as the process would be self-

driving. But it has the disadvantage of being more unpredictable than any other methods. As the

dissociation of clathrate crystals is very endothermic having an enthalpy of dissociation value of

+55KJ/mol at 273K (Ruppel, 2007).This method will most likely be the first production method

tested outside the laboratory. It has also been successful to economically produce gas from gas

hydrates. (COLLETT, 2004).

Figure 11: Gas production by depressurization process

This process is carried out under following assumptions: (Ayhan Demirbas, 2010)

Hydrate dissociation occurs as soon as the reservoir pressure drops below the dissociation

pressure for the hydrate at the reservoir pressure.

The gas flows immediately to the free-gas zone.

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Hydrate decomposition is proportional to depressurization rate, and follows a first order

kinetic model.

Rock and water expansion during gas production are negligible.

The model neglects heat transfer between reservoir and surroundings.

The reservoir is produced from a single well located at the center.

Under depressurization, the model behaves as a closed system with no boundaries. This method

does not need huge amount of energy expenditure and can be used to drive dissociation of a

significant volume of gas hydrate relatively rapid. In comparison with the thermal extraction

method, the depressurization technique has no heat consumption or losses and is thus highly

feasible. It is the first choice out of all the extraction techniques because it is economical, simple

and easy without auxiliary equipment, and suitable for natural gas hydrate development on a

large scale.

5.3 Inhibitor injection

Certain organics for example alcohols, methanol or ethylene glycol and ionic (seawater or brine)

compounds act as inhibitors. When these compounds injected to the hydrate layer, they

dissociate them by altering the chemical composition of the local pore water to no longer

favorable for hydrate stability. These chemicals would lower the freezing point of neighboring

water, free trapped gases and the gases would again be collected by the same well head.

The advantage of using this method is that the dissociation rates theoretically could be controlled

by adjusting amounts of inhibitor fluids. These inhibitors would also prevent hydrates from

clogging pipelines and well heads during collection (Rupple, 2007).

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Figure 12: Gas production by chemical inhibitor injection process

An interesting application of the inhibitor injection process is that CO2 could possibly be used as

dissociation element. could be used in conjunction with natural gas for sequestering carbon

dioxide out of atmospheric circulation because can replace methane in clathrates (Ruppel,

2007). For example the US Department of Energy has recently completed a successful test on a

methane hydrate well located on AlaskasNorth slope. Carbon dioxide and nitrogen are injected

into the hydrates to release the methane. The pressure was then lowered so that methane gas

could be extracted. Nitrogen was added to the concept as it was thought that it would produce a

gas saturation by which the could travel and affect exchange without converting directly to

- hydrate. However that has other impacts as well, including partial pressure effects that

dissociate near-well-bore hydrate.

As it can be seen in figures 11 through 13, methane could potentially be extracted from gas

hydrates without co-production of significant volumes of water. Furthermore, the injected CO2

would be sequestered as gas hydrate within the pressure-temperature stability field for CO2hydrate.

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13

Figure 13: A schematic figure of a well

Figure 14: Injection of into the well (the blue stream) Figure 15: the release of methane through thepipes (the red stream)

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6. Methane Hydrates as Potential Source

The increasing demand for energy resources has made methane hydrates very important. But

their commercial production has been a question for researchers for decades. The advancement

in technology has proved that these hydrates can be produced on commercial scale. These

untapped reservoirs of energy are considered to meet energy needs for next thousand years

(TheEnergy Lab, 2011). The massive amount of gas hydrates under the ocean and beneath arctic

permafrost represents an estimate of more than 50 percent of all carbonaceous fuel reserves on

earth. Hence, gas hydrates provide an energy supply assurance for the 21st century. Countries

that have traditionally relied on oil and gas imports for their energy needs, will become self-

sufficient because of the vast gas hydrate reserves contained in their nearby continental slopes.

Within the next ten years, Japan will commercially exploit gas hydrates from its surrounding

offshore basins (Ayhan Demirbas, 2010). Likewise, North Americans need not to worry about

energy supply as gas hydrates will fill in the gaps left by conventional exploration. Technologies

are being evolved to make gas hydrate exploitation feasible and economically viable in a variety

of deep water and permafrost settings.

6.1 Methane Hydrate Pyramid

The following pyramid is showing the large deposits of hydrates along with therecoverable amounts of these hydrates, which is pretty optimistic.

Figure 16: the methane hydrate resource pyramid.(The Energy lab,2011)

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According to this pyramid, the estimated amount of hydrates in arctic sands is in 100s Tcf.

Similarly, in marine sands they are estimated in 10000s Tcf. The amount of these recoverable

reserves is increasing with depth. So, the deeper we go, the more hydrates we find. It is also

observed that methane hydrate reservoir can, in principle, hold about six times as much methane

as free gas in the same space. However, the methane hydrate enrichment factor decreases with

depth such that, at the base of a deep reservoir, the methane hydrate holds little more methane in

a given space than free gas does. It limits the potential of deep reservoirs.

However there are two important prospects about the methane hydrates.

Source of energy for the future

Hazards such as climate change

We have to see both factors in comparison whether these hydrates will overcome the hazardous

challenges and prove a source of energy for future. Though there is a lot of research study going

on for the development of methane hydrates, there are four main factors which support the fact

that methane hydrates should be considered as a potential energy source.

6.2 Wide Geographical Distribution

Researchers and scientists believe that global abundance and distribution of methane hydrates

suggest that they may become energy resources for the future. With increasing energy demand

and depleting energy resources, gas hydrates may serve as a potentially important resource of

future energy requirements. They are distributed widely throughout the world. So, the countries,

relying on import resources can have them in their nearby location.

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Figure 17: location of sampled and inferred gas hydrate occurrences worldwide.(The Energy Lab, 2011)

6.3 Their Occurrence at Shallow Depths

The conditions suitable for the occurrence of gas hydrate exist in a few hundred meters of the

rapidly accumulating continental margins. Theoretically, gas hydrate occurrence up to 250 m is

possible when thermogenic gases are involved. In the Gulf of Mexico, gas hydrate occurrence

has been reported up to about 440 m (D. Depreiter, 2005). Here we have gas hydrates at a water

depth up to nearly 350 m. The uppermost limit for methane hydrate occurrence is about 500 m

(D. Depreiter, 2005).

An estimate of the quantity of gas hydrate in the Mercator mud volcano was calculated based on

the seismic data and a gas hydrate volume percentage of 5 percent. Volume percentage estimates

for Ginsburg mud volcano were 4 to 19 percent and at the Hydrate Ridge conclude gas hydrates

contents up to 26 volume percent at the summit of the ridge and an average of about 3 to 6

volume percent in the upper tens of meters of sediments in the GHSZ (D. Depreiter, 2005).

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6.4 Higher Energy Potential and Energy Demands

Methane hydrates are considered to contain higher energy potential as compared to other

unconventional energy resources like coal beds, tight sands, block shales, deep aquifers and

conventional natural gas resources.

Figure 18: distribution of organic carbon on earth(excluding dispersed carbon in rocks and sediments)

6.5 Environment Friendly

Methane gas is the only environment friendly among all fossil fuels. The ratio of emission of

carbon dioxide is way less than all other fossil fuels like oil and coal. The combustion of

methane with air is much cleaner than the combustion of all other fossil fuels.

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Figure 19: increasing demand of gas in future(Patrick Hendriks, Gassco, October 31, 2012))

The figure above shows that the dependency on energy resources in future. Here, graph

illustrates that; the amount of carbon dioxide in atmosphere will be way lesser if we use methane

as energy resource.

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7. Challenges

7.1 Global Climate Changes

The dependency on energy resources especially on fossil fuels is causing the climate changes

rapidly. The increasing amount of carbon dioxide in atmosphere is the basis for green house

effect which ultimate cause global warming. Methane is also a greenhouse gas which is more

efficient than carbon dioxide.

It is believed that global warming will lead to the destabilization of gas hydrates in the oceans

and in permafrost areas at shallow depths. These areas will then release large volumes of

methane in the atmosphere over a relatively short period of time. When this methane will be

combined with carbon dioxide in atmosphere, the additional greenhouse effect will be produced.

This will give a boost in increase of global warming which leads to more disastrous

consequences for this world. Additional factors such as the shutdown of the hermohaline

circulation1, warming up of the world oceans, and the further disastrous release of gas hydrates

from unstable slope settings, would feed into it (Beauchamp, 2004). This will shift the world

climate into an alternate state, marked by very warm and inhospitable conditions on land.

The researchers believe that the rock record provides few examples in which global warming

events likely coupled with massive and apparently rapid release of methane from gas hydrates.One of these is the Late Paleocene Thermal Maximum (LPTM), which recorded a large shift in

global temperatures over a period of probably less than a few thousand years (Beauchamp,

2004). Mass balance considerations have suggested a rapid influx of large volume of isotopically

light carbon into the worlds oceans. It is believed that the LTPM was caused, or at least

accompanied, by a massive release of gas hydrate methane in the environment. The influx of

greenhouse efficient methane into the atmosphere would have contributed to a positive feedback

mechanism, which presumably led to a more than 10 C increase in many parts of the world as

shown by oxygen isotopes of fossils and carbonate sediments. The release of methane hydrate

gas was over millions of years.

1Theterm thermohaline circulation (THC)[1]refers to a part of the large-scale ocean circulation that is driven by globaldensity

gradients created by surface heat and freshwaterfluxes.
http://en.wikipedia.org/wiki/Thermohaline_circulationhttp://en.wikipedia.org/wiki/Thermohaline_circulation#cite_note-1http://en.wikipedia.org/wiki/Thermohaline_circulation#cite_note-1http://en.wikipedia.org/wiki/Thermohaline_circulation#cite_note-1http://en.wikipedia.org/wiki/Density_gradienthttp://en.wikipedia.org/wiki/Density_gradienthttp://en.wikipedia.org/wiki/Fluxhttp://en.wikipedia.org/wiki/Fluxhttp://en.wikipedia.org/wiki/Density_gradienthttp://en.wikipedia.org/wiki/Density_gradienthttp://en.wikipedia.org/wiki/Thermohaline_circulation#cite_note-1http://en.wikipedia.org/wiki/Thermohaline_circulation

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In response to this issue, researchers propose that methane seepages on the modern sea floor are

always associated with some levels of microbial oxidation. Methane becomes the energy source

to a variety of bacterial fauna that can develop rapidly, and produce both organic films and

antigenic carbonates that incorporate depleted carbon. The biogenic oxidation of methane also

generates CO2as by-product. The CO2released in the water column either escapes to the

atmosphere, and thus contributes to greenhouse warming, or is utilized by the phytoplankton

before reaching the surface. Hence, a synchronous record of depleted carbonates and organic

matter in the sediments does not necessarily designate a significant release of methane. A release

of methane from gas hydrates is just as likely to generate a microbial bloom in the ocean as

global warming in the atmosphere. For methane to be a warming agent it has to bypass normal

fermentation processes, and therefore has to be released very rapidly and in huge amount as well.

Neither a slow, progressive release of large volumes of methane, nor rapid releases of small

volumes of methane are likely to lead too much global warming.

7.2 Energy Resources

Identification and estimation of any energy resource has always been a challenge. The worldwide

estimates of methane hydrates are suspicious. They do not guarantee that these hydrates will

provide energy supply assurance for the future. These estimates are based on the cumulative

knowledge of the architecture and petroleum system of a given basin. The gas hydrate system is

a subset of the broader petroleum system. To understand this system, one should understand that

whether hydrates have formed, whether they are concentrated enough to be exploited, and

whether they are recoverable in any sort of way. A simple knowledge of the vertical and lateral

extent of the GHSZ is insufficient. A well-defined BSR does not guarantee huge reserves

(Beauchamp, 2004). It only means that a free gas hydrate interface has developed. Likewise the

presence of one large field in an area does not guarantee the occurrences of others. Producing gas

hydrates from different porous rocks is also questionable.

All these were valuable few years ago. But recent advancement in technology has explained

most of them experimentally. There are a few experimental cases which successfully

demonstrate that these hydrates are potential source of energy. One example is Messoyakha field

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in west Siberian basin. There scientists shifted the thermodynamic phase boundary between solid

hydrates and gaseous methane using inhibitors, such as methanol or glycol. Producing methane

from gas hydrates using methanol or glycol injections has been attempted in the vast

Messoyakha field, with positive results (Beauchamp, 2004).

Second development is at Mallik field in Canada. Thermal injection was performed in a genuine,

yet short-lived, production test at Mallik in 2002. Numerical models have shown this technique

has some potential under certain conditions. Scientists came up with great results and prospects.

A couple of years ago, Japanese and Canadian researchers returned to the Mallik site to conduct

a longer duration production test in a hydrate bearing interval near the bottom of the methane

hydrate stability zone. A six day pressure drawdown test resulted in sustained, stable gas flow

from hydrate. The success of this production test was a major step towards verifying the

productivity of methane from hydrates (TheEnergy Lab, 2011) (Beauchamp, 2004).

Figure 20: location of Mallik well in Canada.(The Energy Lab,

2011)

Figure 21: Natural Gas flare at Mallik site.(The Energy Lab,

2011)

Now we can believe that the estimates of gas hydrates are no longer suspicious as they were inprevious years. The amount of natural gas stored in natural gas hydrates is estimated at about

20000 trillion m3, a figure nearly two order of magnitudes larger than recoverable conventional

gas resources. Hence, gas hydrates provide an energy supply assurance for the 21st century.

Countries that have traditionally relied on oil and gas imports for their energy needs will become

self-sufficient because of the vast gas hydrate reserves contained in their nearby continental

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slopes. Technology will quickly evolve to make gas hydrate exploitation feasible and

economically viable in a variety of deep water and permafrost settings.

7.3 Sedimentary Instability and Failure

It is believed that if we start producing methane hydrates in large amount, we may face

catastrophic results. Dissociation of these hydrates may cause sedimentary instability which is

devastating for coastal environments and human infrastructures. This deep sea erosion may lead

to drastic results in the form of land sliding, tsunamis and canyons.

The facts from the history show that sedimentary destabilizations has caused these catastrophic

changes centuries ago (Beauchamp, 2004). So, there is a possibility of devastation by producing

these hydrates.

Researchers suggest two solutions to minimize and also avoid these risks. As this process

usually happens in overpressure zones so, we can produce hydrates by maintaining pressure

through injection of some other gas, like CO2. The other solution is to keep hydrate production

beyond the risk limit. Careful studies of rock mechanics and amount of recoverable reserves can

be helpful.

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8. Economic Aspects

Regardless of huge estimates of potential hydrates, commercial interest in exploring them has not

been developed yet. Several countries including Canada, India, Japan and USA have launched

their ambitious programs for exploring them. India has not explored them yet but BSRs indicate

enormous amount of hydrates. On the other hand, Japan has started a major program to drill in

Nankai Trough as well as in Mackenzie River delta of Canadian Arctic (G.P. Glasby, 2003).

The economics of producing GHDs are not well understood because there are too many

unknowns. In addition, each GHD will be different, so different technologies may have to be

employed. Experience with the Messoyakha field provides an invaluable source of information

and shows that the cost required to produce the GHD is only about 15% to 20% higher than for a

conventional gas field in the same area.

Commercial development of an offshore GHD will be more expensive than a conventional

offshore field. But expenditures for drilling GHDs are considerably lower than for drilling gas

deposits, because GHDs will be shallower. Better formation evaluation will be needed to better

define the GHD and to improve the economics of GHD development. The most important

question is the creation of highly effective technologies for the in-situ conversion of gas from the

solid hydrate state into the free gaseous state directly in the reservoir.

Methane has 80 percent heat content of the crude oil. A barrel of methane contains 4.62 million

BTU of heat energy compared to the barrel of crude oil that produces 5.85 million BTU of heat

energy (Andrew Lonero, 2009). Therefore, extracting methane from hydrates could be making

economically viable if the gas is priced between $4 and $6 per thousand cubic feet, using the

same existing equipment (Ruppel, 2007).

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9. Discussion

Gas hydrate may be considered a future energy source not because the global volume of hydrate

bound gas is large, but because some individual gas hydrate accumulations may containsignificant and concentrated resources that may be profitably recovered in the future. Methane

hydrates are more evenly distributed on the planet than any other sources of hydrocarbons. The

energy concentrated in natural gas hydrates can serve as an unconventional energy source which

is very important to maintain the growing energy needs for several decades.

Producing natural gas from methane hydrate will require that we find economical methods for

safely extracting the methane, while minimizing environmental impacts. Some progress has been

made in this area, but much remains to be understood. But, even with the existing technologies,

the production of methane hydrates will soon be accessible to many countries. However further

research and development will be necessary before it can be developed economically.

However there is one complication in extraction of methane from methane hydrates. As it has

been mentioned earlier, the extraction process requires the dissociation of methane hydrates, but

hydrate dissociation is an endothermic process. So, a natural consequence of dissociation is

cooling and potential re-freezing of adjacent portions of the reservoir. To be successful, a

methane hydrate production strategy must include sufficient depressurization to cause the

hydrate to dissociate and, in some cases, the addition of localized heating to overcome the

natural tendency of the hydrate in the reservoir to return to its stable, frozen state. And also

methane hydrate wells will be more complex than most gas wells because of a number of

technical challenges, including: maintaining commercial gas flow rates with high water

production rates; operating at low temperatures and low pressures in the wellbore; controlling

formation sand production into the wellbore; and ensuring the structural integrity of the well.

Technologies exist to overcome all of these issues, but the use of them will add to overall

development costs for producing natural gas from hydrate. However with all these challenges

future development would need to use techniques that minimize the release of methane to the

atmosphere. And development activities in both arctic and marine settings would need to be

carried out in ways that maximize protection of these environments.

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10. Conclusion

Methane clathrates are valuable minerals that can be found in marine sediment beds on

continental shelves. They are widely spread throughout the world. Gas hydrates are crystallinestructures formed by the mixture of natural gas and water under specific conditions of low

temperature and high pressure. They have drawn so much attention in past decade because they

are new clean energy resources which have not been explored yet.

In order to get the most out of these hydrates, numerous methods for their extraction have been

developed which can be used to commercially produce them. The development of these methods

has helped us to overcome hazards and challenges related to environmental issues, economic

recovery and commercial production problems. For those countries who have not been blessed

with traditional gas reserves, methane hydrates can be potential lifeline for their economy.

Currently we are in transition stage of methane hydrate development. This transition is more of a

scientific theory than practical extraction of methane hydrates. The hazardous issues may limit

their production. But successful production at Mallik and Messoyakha fields shows a remarkable

development in this area.

The role of companies and countries in investing both time and significant amount of money,

determines their seriousness for extracting methane hydrates. The energy companies and

research institutes are trying to develop new and safe ways to adapt these hydrates as future

energy resource.

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11. References

1. Ayhan Demirbas,2010, Methane hydrates as potential energy resource: Part 2Methane

production processes from gas hydrates, Energy Conversion and Management 51 (2010) 15621571

2. Sang-Yong Lee, Gerald D. Holder,2001, Methane hydrates potential as a future energy source, Fuel

Processing Technology 71 2001 181186

3. National Energy Technology Laboratory; U.S. Department of energy, 2011,Energy Resource Potential

of Methane Hydrate

4. Y.F. Makogon, S.A. Holditch, T.Y. Makogon, 2007, Natural gas-hydrates A potential energy source

for the 21st Century, Journal of Petroleum Science and Engineering 56 (2007) 1431

5. D. Depreiter, J. Poort, P. Van Rensbergen, and J. P. Henriet, 2005, Geophysical evidence of gas

hydrates in shallow submarine mud volcanoes on the Moroccan margin, Journal of Geophisical

Research, vol. 110, B10103

6. Yuri F. Makogon, Hydrates of Natural Gas, Petroleum Engineering-Up Stream; Texas A&M University,

College Station, USA

7. Ryo Matsumoto, Yoshitaka Kakuwa, Manabu Tanahashi, 2011, Occurrence And Origin Of Shallow

Gas Hydrates Of The Eastern Margin Of Japan Sea As Revealed By Calypso And Casq Corings Of R/V

Marion Dufresne, Proceedings of the 7th International Conference on Gas Hydrates (ICGH 2011)

8. Jn Steinar Gumundsson, 2012, Flow Assurance Solids, Department of Petroleum Engineering and

Applied Geophysics NTNU

9. Jn Steinar Gumundsson , 2012, Our Technical Writing, Department of Petroleum Engineering and

Applied Geophysics NTNU

10.Patrick Hendriks, 2012, Norwegian Gas to Europe(Gassco Presentation for NTNU), Department

Manager Process Technology and Technical Safety

11.Jon Barratt Nyster & Vanessa Wottrich, 2012, Gas Markets 101(Statoil Presentation for NTNU),

Market Analysis, Natural Gas

12.Kristian Sandengen, 2012, Hydrates and Glycols(Statoil Presentation for NTNU), MEG (MonoEthylene glycol) Injection and Processing

13.Zhen-guo Zhang ,Yu Wang, Lian-feng Gao, Ying Zhang, Chang-shui Liu, 2012, Marine Gas Hydrates:

Future Energy or Environmental Killer? , Energy Procedia 16 (2012) 933938

14.Ayhan Demirbas, 2010, Methane hydrates as potential energy resource: Part 1Importance,

resource and recovery facilities, Energy Conversion and Management 51 (2010) 15471561

8/12/2019 12 Khamen Eh

32/33


27

15.Ayhan Demirbas, 2010, Methane hydrates as potential energy resource: Part 2Methane

production processes from gas hydrates, Energy Conversion and Management 51 (2010) 15621571

16.Benot Beauchamp, 2004, Natural gas hydrates: myths, facts and issues, C. R. Geoscience 336 (2004)

751765 Concise Review Paper

17.G.P. Glasby ,2003, Potential impact on climate of the exploitation of methane hydrate deposits

offshore, Marine and Petroleum Geology 20 (2003) 163175

18.Savvas G. Hatzikiriakos and Peter Englezos, 1993, The Relationship Between Global Warming

And Methane Gas Hydrates In The Earth, Chemical Enginming Sckmx, Vol. 48, No. 23.

19.Kim Senger, 2009, First-order estimation of in-place natural gas resources at the Nyegga gas hydrate

prospect, mid-Norwegian Margin, Masters Thesis in Geology;Faculty of Science,Department of

Geology University of Troms

20.J.W. Pohlman, M. Kaneko, V.B. Heuer, R.B. Coffin, M. Whiticar, 2009, Methane sources andproduction in the northern Cascadia margin gas hydrate system, Earth and Planetary Science Letters

287 (2009) 504512

21.Luzhi Xu, Xu Wang, Liuxia Liu, Minghui Yang, 2011 ,First-principles investigation on the structural

stability of methane and ethane clathrate hydrates, Computational and Theoretical Chemistry 977

(2011) 209212

22.Brendon K. Chastain, Vincent Chevrier ,2007,Methane clathrate hydrates as a potential source for

martian atmospheric methane, Planetary and Space Science 55 (2007) 12461256

23.Hisashi O. Kono, Sridhar Narasimhan, Feng Song, Duane H. Smith, 2002, Synthesis of methane gas

hydrate in porous sediments and its dissociation by depressurizing, Powder Technology 122 (2002)

239246

24.Arvind Gupta, Jason Lachance, E.D. Sloan Jr., Carolyn A. Koh, 2008, Measurements ofmethane

hydrate heat of dissociation using high pressure differential scanning calorimetry, Chemical

Engineering Science 63 (2008) 58485853

25.Caroline Thomas, Olivier Mousis, Sylvain Picaud, Vincent Ballenegger, 2009, Variability of the

methane trapping in martian subsurface clathrate hydrates, Planetary and Space Science 57 (2009)

4247

26.G.P. Glasby, 2003, Potential impact on climate of the exploitation of methane hydrate deposits

offshore, Marine and Petroleum Geology 20 (2003) 163175

8/12/2019 12 Khamen Eh

33/33


27.J.W. Pohlman, J.E. Bauer, E.A. Canuel, K.S. Grabowski, D.L. Knies, C.S. Mitchell,M.J. Whiticar, R.B.

Coffin, 2009, Methane sources in gas hydrate-bearing cold seeps: Evidence from radiocarbon and

stable isotopes, Marine Chemistry 115 (2009) 102109

28.Qing Yuan, Chang-Yu Sun, Xin Yang, Ping-Chuan Ma, Zheng-Wei Ma, Bei Liu, Qing-Lan Ma,Lan-Ying

Yang, Guang-Jin Chen, 2012, Recovery of methane from hydrate reservoir with gaseous carbon

dioxide using a three-dimensional middle-size reactor, Energy 40 (2012) 47e58

29.Shigenao Maruyama, Koji Deguchi, Masazumi Chisaki, Junnosuke Okajima, Atsuki Komiya,Ryo

Shirakashi, 2012, Proposal for a low CO2 emission power generation system utilizing oceanic

methane hydrate, Energy 47 (2012) 340-347

30.Junfang Zhang, Zhejun Pan, 2011, Effect of potential energy on the formation of methane hydrate,

Journal of Petroleum Science and Engineering 76 (2011) 148154

31.Xuemei Lang, Shuanshi Fan, Yanhong Wang, 2010, Intensification of methane and hydrogen storagein clathrate hydrate and future prospect, Journal of Natural Gas Chemistry 19(2010)203209

32.zoneJinan Guan, Deqing Liang, Nengyou Wu, Shuanshi Fan,2009, The methane hydrate formation

and the resource estimate resulting from free gas migration in seeping seafloor hydrate stability

zone, Journal of Asian Earth Sciences 36 (2009) 277288

33.Dr. William Dillon, 2003,Methane trapped in marine sediments as a hydrate represents such an

immense carbon reservoir that it must be considered a dominant factor in estimating

unconventional energy resources; the role of methane as a 'greenhouse' gas also must be carefully

assessed, U.S. Geological Survey 2003

34.http://en.wikipedia.org/wiki/Messoyakha_Gas_Field (22/10/2012)
http://en.wikipedia.org/wiki/Messoyakha_Gas_Fieldhttp://en.wikipedia.org/wiki/Messoyakha_Gas_Fieldhttp://en.wikipedia.org/wiki/Messoyakha_Gas_Field

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