Unconventional Energy; Methane Hydrates.

Scientists believe that  there could be more valuable carbon fuel stored in the vast methane hydrate deposits scattered under the world's seabed, permafrost and arctic ocean than in all of the known reserves of coal, oil and gas put together.  

Probably the most pressing and urgent question facing mankind today involves the security for future energy resources. This in turn has led to intensification and extension of exploration and development efforts for new sources of oil and gas. Methane-hydrates is the most promising unconventional energy source on the planet.   The Arctic Ocean is geologically promising and due to the cold environment, highly attractive for very large scale deposits of clean hydrate gas.

The Energy Information Administration (EIA) recently predicted that world consumption of natural gas alone will rise by 91% to 182 trillion cubic feet in less than twenty-five years. The development of Arctic hydrates would alleviate the envisaged severe shortages from dwindling existing conventional gas supplies.

Gas is used to make fertilizer for food production. It is estimated that for every gram of carbohydrates we consume, 10 grams of hydrocarbons have been used to make that 1 gram of food.

Recent Harts E_P article on Methane Hydrates production.

The Arctic could become the world's largest source for clean gas energy supplies over the next decades.

At relatively low temperatures and high pressures, some light natural gases can combine with water to create crystalline substances resembling ice. These solid compounds are called clathrate hydrates of gas, or more conveniently, “gas hydrates” or "methane-hydrates"  Since the late 1960s, researchers have found methane-rich gas hydrates in sediments of the deep ocean and beneath permafrost regions. Such gas hydrates store a tremendous amount of methane, which if liberated, could supply bountiful clean energy.

The energy potential is staggering.  According to the U.S. Geological Survey (USGS), 100,000 to 300 million trillion cu. ft. (tcf) of methane exists globally in hydrate form--most of it in the ocean floor. There's more energy potential locked up in methane hydrate formations across the world than in all other fossil energy resources combined.  At current consumption rates, that's enough to supply the entire world's demand for a 1,000 years or more. Probably the largest commercially viable deposits are in the already frozen Arctic.

The sediments of large portions of the Arctic Ocean floor are conducive to methane-hydrate formation.   Elsewhere in the world, most marine hydrates are confined to the edges of continents where water is sufficiently deep, cold and where nutrient-rich waters unload partially decayed organic material for bacteria to convert to methane. With the right pressure and temperature combination, these methane molecules are eventually entrapped in icy crystalline cages, forming undersea deposits of gas hydrates. There is often free gas and sometimes oil deeper underneath.

The entire central Arctic Ocean is believed to be underlain with a 50 million year-old, 2 miles thick layer of high azolla organic content hydrocarbon source rocks providing untold tonnages of methane, much of it subsequently compressed and frozen into hydrates.

One day soon arctic methane-hydrates will be reclassified from a vaguely defined "resource of the future" to a recognized part of the world's clean energy portfolio providing a significant contribution to the earth's future energy supply. There is no question that arctic methane hydrate is the cleaner hydrocarbon fuel of the future.  Methane Hydrates are stable at locations of high pressure and low temperature found in the arctic ocean floor.

Extraction of arctic methane from hydrates will one day provide an enormous cleaner energy and petroleum feedstock resource. Additionally, methane-hydrates are an excellent indicator of deeper gas and oil resources which are usually trapped beneath shallower methane-hydrate layers in ocean floor sediments.

By burning methane or using it in fuel cells, the methane is converted to CO2. - just like burning coal or oil. Combustion of methane, however, is more CO2-efficient than that of any other hydrocarbon, e.g., twice as efficient as burning coal. Hence, using methane from gas hydrate as an energy resource would be, compared to other hydrocarbons, relatively climate friendly.

While the west postulates methane-hydrates the Russians have been producing from it for years.   The Messoyakha gas field in the frozen northern Russia is an excellent example of a hydrocarbon accumulation from which gas has been produced commercially from hydrates, mostly by simple reservoir depressurization.  At least one-third and, most likely, two-thirds of the Messoyakh reservoir, which for 13 years has been in commercial production, occurs in the form of natural gas hydrates.  It is conservatively estimated that about 36% (about 5 billion cubic meters) of the gas withdrawn from the field has come from the gas hydrates.

                                                                        Messoyakha gas field

The field was developed for conventional gas, and scientists have long believed that the long sustained gas production was due to the contribution of gas from gas hydrate into an underlying free-gas accumulation.  The long production history of the Messoyakha field demonstrates that gas hydrates are an immediately producible commercial source of natural gas in arctic climates and that production can be started simply and maintained by “conventional” methods. 

Long-term production from the gas-hydrate part of the Messoyakha field is presumed to been achieved by the simple depressurization scheme. As production began from the lower free-gas portion of the Messoyakha field in 1969, the measured reservoir-pressures followed predicted decline relations; however, by 1971 the reservoir pressures began to deviate from expected values. This deviation has been attributed to the liberation of free-gas from dissociating gas hydrates.

The gas production zone is at a depth of 870 m and hydrate zone ranges from 250 to 870 m. The maximum measured gas production in well #133 was 250,000 m3/day and in well #142 was 200,000 m3/day and after a methyl alcohol treatment, gas rates increased two to ten fold.

 

               Ice that burns                       Mallik 2002. Hydrate Gas production test

Methane hydrates typically look like dirty chunks of ice, but if touched by a flame, the ice burns.

Apart from large scale conventional oil and gas potential, the Arctic is known to contain extraordinarily  large quantities of methane hydrates, a combination of gas and water produced in the crushing pressures deep within the earth where the structure is cold - literally, ice that burns.   The world's most promising fossil fuel, arctic methane-hydrates hold great potential as a virtually inexhaustible supply of  “environmentally-friendly” fuel for the 21st Century.

Methane hydrate forms in generally two types of geologic settings: (1) on land in permafrost regions where cold temperatures persist in shallow sediments, and (2) beneath the ocean floor at water depths greater than about 500 meters (about 1,640 feet) where high pressures and sub-zero temperatures dominate. The hydrate deposits themselves may be several hundred meters thick.

Deep-sea sediments host the vast majority of natural gas hydrates, which exist within a pressure- and temperature-limited volume often called the gas hydrate stability zone (GHSZ). Across a typical continental margin, the GHSZ makes a lens beneath the seafloor. Today, this lens begins at 250 to 500 meters water depth because, depending on local conditions, this is where the pressure is high enough and the water temperature low enough to create gas hydrates. From this depth down, the seafloor marks the top of the lens because gas hydrates, like ice, float and cannot accumulate in water. The bottom of the lens lies within the deeper sediment, where temperatures are too warm for gas hydrates. Most deposits have been found in the arctic and along continental margins where high burial rates of organic matter drive considerable production of hydrocarbon gases, particularly methane.   Most gas hydrates, however, occur in the GHSZ well beneath the seafloor as part of a dynamic system, making the Arctic Oceans deeps probably the most prospective region of the earth for very large scale deposits.

The promise of methane hydrate is this: It is a very efficient storehouse of energy. When dissociated, a single cubic foot of solid hydrate releases as much as 180 cubic feet of methane gas. (the chief constituent of natural gas).

Methane hydrates bind immense amounts of methane within sea-floor or Arctic sediments.  The worldwide amount of methane in gas hydrates is considered to contain at least 1x104 gigatons of carbon in a very conservative estimate. This is about twice the amount of carbon held in all fossil fuels on earth.    Methane-hydrate is a crystalline solid consisting of gas molecules, usually methane, each surrounded by a cage of water molecules. It looks very much like water ice. Methane-hydrate is stable in cold ocean floor sediments at water depths greater than 300 meters, and where it occurs, it is known to cement loose gravel and sand sediments in a layer several hundred meters thick.

Methane is produced by the decomposition of organic material in the sediment or by thermal processes similar to those responsible for the formation of oil. As the methane moves through the sediment, it combines with water at the low temperatures and high pressures beneath the ocean to produce an ice-like solid. Methane gas hydrates exist along continental margins worldwide, most in sediments tens to hundreds of meters below the sea floor in waters more than 500 meters deep.   While natural gas takes the form of a gas, methane hydrate is a solid.

Gas hydrates concentrate huge volumes of methane gas by combining methane with water under certain temperature and pressure conditions.  Typically we have a methane molecule within a lattice of water and this forms a solid substance within the pores in the subsurface.  The gas storage capacity’s tremendous — that’s one thing that makes hydrates very attractive as an unconventional gas resource.     When gas hydrate crystals break down or disassociate they can yield 164 to 180 times their volume of free gas.  Hydrates most often occur as discrete grains that form within pores and act as part of the framework of the sediment, rather than as grain coatings or cements.

Hydrates form and stabilize in a very specific zone of high pressure and low temperature, where water solidifies around gas molecules to form a crystalline structure.   Marine sediments in the world's warmer regions such as the northern Gulf of Mexico are likely too warm and salty to hold commercially extractable amounts of methane gas hydrates originally thought to exist in the ocean floor there. The cold Arctic climate has proven to be viable for commercial gas hydrates production.

Mallik

In 2002, at the Mallik site in Canada’s Mackenzie Delta, researchers undertook the first modern, fully integrated field study to test the production potential of natural gas hydrates.   The team of oil companies and scientists from Canada, Japan, India, Germany and the US showed it was possible to produce methane from the icy deposits below Canada's Northwest Territories profitably.    BP and the US government are carrying out similar experiments in Alaska. The international research program involving the Department of the Interior’s U.S. Geological Survey proved conclusively that it is technically and financially feasible to produce gas from gas hydrates.

Well-log responses attributed to the presence of gas hydrates have been obtained in about one-fifth of the wells drilled in the Canadian Arctic Mackenzie Delta, and more than half of the wells in the Arctic Islands are inferred to contain gas hydrates.   The Mallik area alone contains methane-hydrate reserves of more than 4 billion cubic meters per square kilometer.

       

                       Mallik Location                                       Mallik from the Air                   Hydrate-methane in-situ                      Methane-hydrates frozen-in Mallik drill core

Two main extraction methods have been successfully proven at Mellik. The first, called depressurization, involves drilling a hole into the hydrate layer to draw down the pressure, causing hydrates to dissociate and the resulting gas to flow up the pipe. Thermal injection, the second technique, destabilizes hydrates by pumping hot water into the deposit.   Because depressurization requires less energy it is the "lowest-hanging fruit."

Depressurization and thermal heating experiments at the Arctic Mallik site were extremely successful. The results demonstrated that gas can be produced from gas hydrates with different concentrations and characteristics, exclusively through pressure stimulation. The data supports the interpretation that the gas hydrates are much more permeable and conducive to flow from pressure stimulation than previously thought.

Researchers working with the U.S. Department of Energy and BP Alaska on the Alaskan North Slope have successfully conducted industry-standard, field-scale reservoir simulations of discrete gas hydrate prospects. These strands are coming together in Alaska, where geologists are discovering hydrate deposits and developing plans to exploit them.

Economic Viability
Work at the Mallik site in the Canadian Arctic over the past seven years has definitively established that production of methane from hydrates can occur using existing well-based technologies. Furthermore, based on the results of the scientific production response tests conducted at Mallik in 2002, it is now believed that depressurization can result in significant and economically viable volumes and rates of methane production. Research reported at a major petroleum geology conference in September 2004 indicates that, by leveraging existing infrastructure, production can be economical at gas prices on the order of $4 to $6 per thousand cubic feet.

Computer production simulations supported by the project, including those performed by Lawrence Berkeley National Laboratory, have shown that under certain geologic conditions, gas can be produced from gas hydrates at very high rates, exceeding several million cubic feet of gas per day.
 

The reduction of pressure caused by methane-hydrate production conveniently initiates a breakdown of solid hydrates in the vicinity of the well and thus produces an ongoing recharging of the trap with pressurized gas, which flows up the well pipe to the surface.

Projected breakeven wellhead price for Mallik gas hydrates was US$2.85/Mcf, which compares favorably to conventional gas wells at $2.25/Mcf average.

Where there's Gas Hydrates there's often oil:   Large gas hydrate accumulations are known to occur in the so-called Tarn and Eileen trends that lie in an area over parts of the Alaskan Prudhoe Bay, Milne Point and Kuparuk River oil fields — drilling programs associated with these oil fields have found gas hydrates near the surface.   The gas hydrates have accumulated in shallow reservoirs that form part of the same petroleum system as the Prudhoe oil fields that lie below them.  Chemical analysis shows that the gas must have leaked up fault zones from the underlying oil fields.

Gas hydrate deposits can best be viewed as shallow gas fields in which pressure and temperature conditions caused the gas to turn into gas hydrate. Free gas often lies trapped directly below the gas hydrates, where the reservoir rocks dip below the base of the gas hydrate stability zone.

The USGS has estimated that the Tarn and Eileen trends trends together contain as much as 100 trillion cubic feet of gas. That compares with total reserves in place of 47 tcf of conventional natural gas on Alaska's North Slope.

Fresh water forms a major byproduct of gas production from gas hydrates. This fresh water production might provide a viable alternative to seawater desalination plants for supplying water.

Hydrates may become a very stable huge source of natural gas from the Arctic within the next five to 10 years and could one day provide the bulk of the world's gas needs. Part of the huge supply could also be converted to clean-burning methanol for cars, and power plants.  Thus eliminating the energy extortion destabilizing the world today.

Major oil and gas companies, the U.S. Department of Energy, the U.S. Geological Survey, the Minerals Management Service, the National Oceanic and Atmospheric Administration, the National Science Foundation, the Naval Research Lab, and other international organizations are cooperating on methane-hydrates research efforts. All the parties recognize that methane hydrate research will provide enormous global public benefits.

The Deep Towed Acoustic Geophysical System (DTAGS) is particularly well suited to provide high resolution mapping of sub bottom structures in deep water and to map the shape and structure of the BSR for methane gas exploration. Source and receiver array are towed between 200-300 m above the sea floor to have data to resolve sediment structural details < 5 mts in thickness within the upper 600-700 m of sediments.

                     One of the super-giant prospects in the Arctic Ocean Commons Deeps.

                           Known Onshore Arctic Methane-Hydrates

History

In 1964. In a northern Siberian gas field named Messoyakha, a Russian drilling crew discovered natural gas in the "frozen state," methane hydrate occurring naturally.  Subsequent reports of potentially vast deposits of "solid" natural gas in the former Soviet Union intensified interest and sent geologists worldwide on a search for how -- and where else -- methane hydrate might occur in nature. In the 1970s, hydrate was found in ocean sediments.

Extraordinary technological developments in the petroleum industry — 3-D seismic techniques, secondary recovery methods and horizontal drilling, for example — have allowed the extraction of resources once thought to be unavailable. Researchers often compare hydrates to coalbed gas resources, which were also considered to be an unconventional and uneconomic resource in the not-too-distant past. However, once geologists understood the resource, defined the reservoir properties and addressed the production challenges, coalbed gas became an important part of the nation’s energy mix. Now, coalbed gas is a viable fuel in its own right and accounts for almost 10 percent of the natural gas production in this country.   It is probable that the arctic's enormous storehouse of clean natural gas hydrates will soon become economically extractable.

Commercial Methane-hydrates commercial production will likely first be undertaken in the Arctic Circle because those deposits are better defined and of higher resource quality than equatorial marine methane-hydrates.

Much like the production of conventional gas, methane-hydrate development will begin with the highest-quality large-scale resources and slowly expand to more challenging settings. And, as with conventional oil and gas resources, success will depend on the ability to appraise large regions and efficiently find these "sweet spots." The Arctic Commons might well prove to be be one of those sweet spots.

Commercial large-scale production of arctic methane-hydrate will add greatly to assuring the long-term supply of clean natural gas to global markets. It is an environmentally friendly fuel with enormous economic and energy security benefits to the earth.  Ultimately, commercial methane-hydrate development will contribute significantly to the expanded diversification of global cleaner energy supplies and the associated realignment of the global balance of energy power.

Technically it is easier and safer to liquefy, handle, transport, store and degasify Methane-hydrate than LNG.


The Gas Market

Natural gas is an important energy source for Europe, Asia and the US domestic economy, providing almost 23 percent of all US energy used. Natural gas has also proven to be a reliable and efficient energy source that is less polluting than other fossil fuels and is the least carbon intensive.

Natural gas is taking on an ever increasing role in power generation, largely because of increasing pressure for clean fuels and the speed and relatively low capital costs of building new natural gas-fired power equipment. Switching power generation from coal and oil to natural gas significantly reduces carbon dioxide emissions.

Historically, Japan, Korea and Taiwan imports its natural gas, while the the United States has produced much of the natural gas it has consumed with the balance imported from Canada through pipelines, although recently, imports of liquefied natural gas (LNG) have supplemented imports from Canada. By 2025, the US Energy Information Administration estimates natural gas imports will be more than 2.5 times greater than in 2003, and will supply 28 percent of total domestic natural gas consumption.

The United States will consume increasing volumes of natural gas well into the 21st century. U.S. natural gas consumption is expected to increase from about 22 trillion cubic feet today to nearly 31 trillion cubic feet in 2025 -- a projected increase of over 40 percent.  The rest of the world will experience similar demand increases.

Twenty years ago coalbed methane (CBM) was widely dismissed as uneconomical, but today it represents 8 percent of domestic US gas production.
 

SOME LINKS

See; Ice that Burns; http://gtresearchnews.gatech.edu/reshor/rh-ss02/e-gas.html

See also:

Japan Methane Hydrates Research: http://www.mh21japan.gr.jp/english/index.html

 Vancouver Island Gas Hydrates Drilling Report: http://iodp.tamu.edu/publications/PR/311PR/311PR.html

Methane Hydrates Workshops: http://web.uvic.ca/ceor/hydrates/2005pres.html

US DOE: http://www.fe.doe.gov/programs/oilgas/hydrates/index.html


http://www.acs.org/memgen/rxntimes/rxt1097/rt10gas.htm
http://www.aist.go.jp/GSJ/dMG/hydrate/Intro.html
http://www.telusplanet.net/public/jcarroll/HYDR.HTM
http://walrus.wr.usgs.gov/docs/hydrate.html
http://patzek.berkeley.edu/E11/hydrocarbonsources.htm
http://www.fe.doe.gov/remarks/hydrate_052198.html
http://kristall.uni-mki.gwdg.de/homep4.htm
http://www.geocities.com/CapeCanaveral/Hangar/6280/
http://www.geol.msu.ru/deps/cryology/scie.htm
 


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