4.
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What then are natural gas hydrates? Gas hydrates are shown here. The picture shows actual natural gas hydrates recovered from the floor of the Pacific Ocean by a piston core off of Vancouver Island. Gas hydrates are the ice that burns and that is because gas hydrate is a solid thatts composed of gas molecules like methane shown here, that are surrounded by a cage of water molecular. The reason that the gas hydrates are important as a fuel source is because a single volume of gas hydrates stores natural gas very efficiently. When the gas and the water are separated, the volume of the gas increases a hundred and sixty-four times. So you can see that we have this very compact and efficient reservoir for natural gas within the earth. We refer to it as an unconventional reservoir because of the way in which the natural gas is trapped in these cages as opposed to being free in the porous space of the rock. The high energy content of gas hydrates is comparable to, on an in-situ volume basis, that of heavy oil-bitumen and at least five times greater than that of gas from both CBM and tight gas, making gas hydrates the richest non-conventional gas resource. This efficient storage results in a gas reservoir that is comparable to a dry conventional gas reservoir at 16 MPa , which resembles a gas/water contact at ~1.6 km (similar to a Lower Cretaceous Mannville gas pool beneath Highway 2 west of Hobbema, Alberta). This, combined with extensive and ubiquitous regions of gas hydrate stability in polar and marine settings, suggests that gas hydrates are the largest global reservoir of petroleum. Gas hydrates are also important materials affecting geotechnical stability and Earth-ocean-atmosphere systems.
5.
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What then are natural gas hydrates? Gas hydrates are shown here. The picture shows actual natural gas hydrates recovered from the floor of the Pacific Ocean by a piston core off of Vancouver Island. Gas hydrates are the ice that burns and that is because gas hydrate is a solid thatts composed of gas molecules like methane shown here, that are surrounded by a cage of water molecular. The reason that the gas hydrates are important as a fuel source is because a single volume of gas hydrates stores natural gas very efficiently. When the gas and the water are separated, the volume of the gas increases a hundred and sixty-four times. So you can see that we have this very compact and efficient reservoir for natural gas within the earth. We refer to it as an unconventional reservoir because of the way in which the natural gas is trapped in these cages as opposed to being free in the porous space of the rock. The high energy content of gas hydrates is comparable to, on an in-situ volume basis, that of heavy oil-bitumen and at least five times greater than that of gas from both CBM and tight gas, making gas hydrates the richest non-conventional gas resource. This efficient storage results in a gas reservoir that is comparable to a dry conventional gas reservoir at 16 MPa , which resembles a gas/water contact at ~1.6 km (similar to a Lower Cretaceous Mannville gas pool beneath Highway 2 west of Hobbema, Alberta). This, combined with extensive and ubiquitous regions of gas hydrate stability in polar and marine settings, suggests that gas hydrates are the largest global reservoir of petroleum. Gas hydrates are also important materials affecting geotechnical stability and Earth-ocean-atmosphere systems.
10.
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What then are natural gas hydrates? Gas hydrates are shown here. The picture shows actual natural gas hydrates recovered from the floor of the Pacific Ocean by a piston core off of Vancouver Island. Gas hydrates are the ice that burns and that is because gas hydrate is a solid thatts composed of gas molecules like methane shown here, that are surrounded by a cage of water molecular. The reason that the gas hydrates are important as a fuel source is because a single volume of gas hydrates stores natural gas very efficiently. When the gas and the water are separated, the volume of the gas increases a hundred and sixty-four times. So you can see that we have this very compact and efficient reservoir for natural gas within the earth. We refer to it as an unconventional reservoir because of the way in which the natural gas is trapped in these cages as opposed to being free in the porous space of the rock. The high energy content of gas hydrates is comparable to, on an in-situ volume basis, that of heavy oil-bitumen and at least five times greater than that of gas from both CBM and tight gas, making gas hydrates the richest non-conventional gas resource. This efficient storage results in a gas reservoir that is comparable to a dry conventional gas reservoir at 16 MPa , which resembles a gas/water contact at ~1.6 km (similar to a Lower Cretaceous Mannville gas pool beneath Highway 2 west of Hobbema, Alberta). This, combined with extensive and ubiquitous regions of gas hydrate stability in polar and marine settings, suggests that gas hydrates are the largest global reservoir of petroleum. Gas hydrates are also important materials affecting geotechnical stability and Earth-ocean-atmosphere systems.
11.
Canada is an Arctic and marine nation, and gas hydrates are confirmed or inferred to occur widely in its continental margins and permafrost regions. The total in-situ amount of methane in Canadian gas hydrates is estimated to be 1,553 to 28,593 TCF (0.44 to 8.1 x 1014 m3), as compared to a conventional Canadian gas potential of ~953 TCF (0.27 X 1014 m3). The geographic distribution of Canadian gas hydrates is:
Region ; Imperial Measure Metric Measure
Mackenzie DeltaaBeaufort Sea ; 300 to 350 TCF ; 8.82 to 10.23x1012 m3 Arctic Archipelago ; 671 to 21,886 TCF; 0.19 to 6.2 x 1013 m3
Atlantic Margin ; 671 to 2,753 TCF ; 1.9 to 7.8 x 1013 m3
Pacific Margin ; 113 to 847 TCF; 0.32 to 2.4 x 1013 m3
Gas hydrate accumulations are also identified in Alaska and the offshore U.S.A. This suggests that gas hydrates represent a potential future assurance of North American natural gas supply, if the gas can be recovered economically.
See Also:
Majorowicz, J. A., and Osadetz, K. G., (2001) Basic geological and geophysical controls bearing on gas hydrate distribution and volume in Canada. American Association of Petroleum Geologists, Bulletin, 85/7:1211-1230.
13.
Currently, we do not have the knowledge that we require to produce gas hydrates economically. Attempts to produce gas hydrates, focus on changing the composition from gas hydrates to gas plus water in the reservoir, deep in the earth. There are three main processes that are envisaged for them. One of them is to change the pressure conditions in the earth by drilling a well and either removing other gases or simply exposing the gas hydrates to the lower pressure of the surface thatts provided by the communication of the well. Another technique is to release the natural gas by the injection of steam or hot water which will destabilize the gas hydrate, and the third opportunity is to change the chemical conditions for gas hydrate formation by the introduction of a chemical inhibitor like methanol. So the plan is to try to determine which of these opportunities might be economically viable and practical from an engineering point of view.
Using conventional technologies the most favorable production situations occur where a produced associated fluid, free gas or confined water, transmits dissociation energy to a large reservoir area, requiring nothing more than lifting costs. Initial commercial production was, and will continue to be, from select accumulations located with, or near conventional developments, where the gas hydrate enhances the total recoverable reserve. Novel technologies could increase the number and type of recoverable accumulations.
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Gas hydrates occur extensively within Canadaas Mackenzie Delta, Beaufort Sea Basin and in the Arctic Islands, both on shore and off shore. Many of the sub sea gas hydrates here are actually thick relics of the last time when sea level was lowered by water being locked up in the continental ice sheets. The reason that these gas hydrates are of immediate interest to us is because of their opportunity to augment the production of natural gas in the Mackenzie Delta which is the site of the a proposed major pipeline project. And the details of gas hydrates occurrence in the Mackenzie Delta have been actively investigated by an international group of researchers lead by Scott Dallimore at the Mallik Bay Gas Hydrate Research Well. Well, why go to the Mallik Research Site? First, Mallik is a great place to look for gas hydrates. Since Imperial Oil first encountered them in the early 19700s, theyyve been well characterized and the geological survey of Canada and the Japan National Oil Corporation went there subsequently in 1998. We know then that there are over two hundred metres of gross gas hydrate thickness within the rock layers. There are very high concentrations of gas within the gas hydrates there, up to ninety percent of the cages are filled with gas in the hydrates. Therees extensive engineering and geophysical data from the site because of the number of wells that have been drilled there and the other scientific investigations.
15.
The site is very interesting internationally because the temperature conditions in the earth at Mallik are quite similar to many of the temperature conditions on the continental shelves of the earth. And so itts a good place to study gas hydrates as a model for what might go on the continental shelves from an accessible, onshore location. And of course, Mallik that is very close to one of the major anchor fields for the proposed pipeline has a very large gas resource.
The Mallik Research Wells in 2002 had the objective of characterizing the production response of a gas hydrate, both in response to the reduction of pressure and to active heating and most important, a comprehensive international science program was associated with the experiment, both to characterize the gas hydrates and to evaluate the results of the production.
See Also:
Dallimore, S.R., Collett, T.S. (editors); Scientific Results from Mallik 2002 Gas Hydrate Production Research Well Program, Mackenzie Delta, Northwest Territories, Canada. Geological Survey of Canada. 2005; Bulletin 585: see last slide.
16.
During the active heating production phase of the test, hot water was heated at the surface pumped down the well and exposed to a seventeen metre thick zone with high gas hydrate saturation for several days. This is the resulting flare from the gas that was produced at surface. The slide describes the details of the test which were are reported on in great detail in the Mallik 2002 GSC Bulletin. These test results were analysed using both the University of Tokyo/Japan Oil Engineering and Lawrence Livermore Berkley National Laboratories reservoir simulators.
The tests should themselves be seen as proof of principal. While the simulations have been successful and even served for subsequent engineering and economic modeling (see below) it will only be with a protracted reservoir test that can be seen to be free of the transient phenomena which are characteristically part of gas well completion and initial production that we will have confidence to project reservoir performance. However, those uncertainties will not prevent me from making some more detailed comments and point you toward some more advance results today.