Minerals Report - International Seabed Authority
Minerals Report - International Seabed Authority Minerals Report - International Seabed Authority
With regard to current knowledge about methane hydrates, Dr. Desa stated that approximately 10,000 gigatonnes of carbon are stored in methane hydrates. He informed participants that this amount of organic carbon is twice the amount contained in currently known fossil fuel. Even if only a small percentage of this amount is recoverable, Dr. Desa said that this represented a major stock of energy. On the subject of how methane hydrates are formed, Dr. Desa explained that they are produced primarily from microbial and thermogenic processes. In the microbial process, Dr. Desa pointed that organic debris within the sediments is decomposed by a complex sequence called methanogenesis into methane by bacteria in an anoxic environment. Decomposition takes place either by acetate fermentation or by the reduction of carbon dioxide. Hydrocarbons, including methane, are formed in the thermogenic process by thermal cracking of organically derived materials. Dr. Desa indicated that this generally occurs at depths greater than 2 kilometres in sedimentary basins where temperatures are in excess of 100° centigrade. He also pointed out that thermogenic methane might also be formed by thermal degradation of oil at even greater depths and by maturation of coal. On prospecting and exploration of submarine methane hydrates, Dr. Desa states that while their presence is detected in drill cores, over large areas gas hydrates can be detected by using acoustical methods such as seismic reflection profiles. He mentioned that chlorinity anomalies in pore water, pore water redox levels, sediment grain size, carbon isotope signatures, and benthic biomass are all proxies that can be used in prospecting for gas hydrates. He also said that pockmarks or gas-escape features of the seafloor are another proxy that can be used in prospecting for gas hydrates. Dr. Desa mentioned that such information is acquired from high-resolution acoustic investigations (side scan imagery, shallow sub bottom profiling). He also mentioned that for the study of any proxies, surficial and shallow sub-surficial sediment samplers are required. An advanced technique that he mentioned is through specially designed pressure core samplers (PCS) within which gas samples can be stored up to minus eighty degrees (-80°C) for later analysis. INTERNATIONAL SEABED AUTHORITY 54
Dr. Desa informed participants that a number of ideas have been discussed for the production and recovery of submarine methane hydrates. These are based on either converting the gas to a fuel, to thermally stimulate the hydrates and melt them, to depressurise it under the hydrate seal or by inhibitor injection using methanol. After production and recovery, Dr. Desa pointed out that the next task was transportation. The three ideas that are being discussed are: Through pipelines on the continental shelf By reducing methane to carbon monoxide and hydrogen and transporting these products, and Facilitating the reaction of methane with water on the seafloor to obtain hydrate free of sediment. The pure hydrate is then stored in zeppelin shaped storage tanks, towed to shallow water infrastructure, and safely decomposed into water and gas in a controlled environment. Dr. Desa mentioned that in addition to India, the United States of America, Japan, Canada, the European Union and Russia have all demonstrated a keen interest in the development of submarine methane hydrates. The significance of methane hydrates he stated is in their tremendous resource potential to meet the world’s energy needs. Dr. Desa stated that in a patent search of the United States, Japanese and European Patent Offices it was discovered that during 1998 and 1999, 400 patents had been issued indicating how people and organizations were positioning themselves for the commercialisation of submarine methane hydrates. 15. A case study in the development of the Namibia offshore diamond mining industry Dr. Ian Corbett, Group Mineral Resources Manager of the De Beers Placer Resources Unit, South Africa, made two presentations. His first presentation was concerned with the development of the offshore diamond mining industry in Namibia. His second presentation was on the development of environmental baselines in a large-open ocean system off southern Namibia by De Beers Marine. INTERNATIONAL SEABED AUTHORITY 55
- Page 12 and 13: deposits and gas hydrates of the co
- Page 14 and 15: Prof. Chris German, Challenger Divi
- Page 16 and 17: Mr. Sven Petersen, Research Associa
- Page 18 and 19: SECRETARIAT Ambassador Satya N. Nan
- Page 20 and 21: is to submit “an application that
- Page 22 and 23: that was established to help protec
- Page 24 and 25: on the continental margin. He state
- Page 26 and 27: with the German firm Preussag. As p
- Page 28 and 29: metre or metres of these black smok
- Page 30 and 31: nodules in terms of these metals -
- Page 32 and 33: Professor Herzig stressed however t
- Page 34 and 35: While noting that the continuity of
- Page 36 and 37: asal diameter at 1,600 m water dept
- Page 38 and 39: discovery of the new hydrothermal s
- Page 40 and 41: esearch cruises dedicated to ferrom
- Page 42 and 43: global mid-ocean ridge system. He p
- Page 44 and 45: athymetric map of the seafloor. A s
- Page 46 and 47: were encouraging. In the course of
- Page 48 and 49: that this matter was sensitive, he
- Page 50 and 51: complete a preliminary evaluation o
- Page 52 and 53: metals - nickel, cobalt, manganese,
- Page 54 and 55: 12. Issues to be taken into account
- Page 56 and 57: entities. Many of them included min
- Page 58 and 59: In this regard, the Secretary-Gener
- Page 60 and 61: According to Dr. Vysotsky, as estim
- Page 64 and 65: Dr. Corbett gave a brief account of
- Page 66 and 67: River resulting in the introduction
- Page 68 and 69: Ms. Zaamwani pointed out that as th
- Page 70 and 71: geochemical and geotechnical survey
- Page 72 and 73: of its continental shelf through bi
- Page 74 and 75: also stated, is similar to that of
- Page 76 and 77: Chapter 7 Technical requirements fo
- Page 78 and 79: Table 1: Classification of marine m
- Page 80 and 81: Volcanogenic Metalliferous sediment
- Page 82 and 83: deposits, including massive sulphid
- Page 84 and 85: 3. Marine Minerals Related to Deep
- Page 86 and 87: The black smoker chimneys dischargi
- Page 88 and 89: contain metals are present at discr
- Page 90 and 91: Figure 4. A diagrammatic east-west
- Page 92 and 93: and refining of these crusts is mor
- Page 94 and 95: distances of hundreds of kilometres
- Page 96 and 97: 2) Deep ocean hot springs at massiv
- Page 98 and 99: 6. P.A. Rona, M.D. Hannington, C.V.
- Page 100 and 101: 25. M.J. Cruickshank (1998), Law of
- Page 102 and 103: With regard to marine mineral depos
- Page 104 and 105: Focussing on sites of sea floor min
- Page 106 and 107: scientific journal "Nature". The su
- Page 108 and 109: Professor Rona recalled that the in
- Page 110 and 111: like St. Stephen’s in the Kremlin
With regard to current knowledge about methane hydrates, Dr. Desa<br />
stated that approximately 10,000 gigatonnes of carbon are stored in methane<br />
hydrates. He informed participants that this amount of organic carbon is<br />
twice the amount contained in currently known fossil fuel. Even if only a<br />
small percentage of this amount is recoverable, Dr. Desa said that this<br />
represented a major stock of energy.<br />
On the subject of how methane hydrates are formed, Dr. Desa<br />
explained that they are produced primarily from microbial and thermogenic<br />
processes. In the microbial process, Dr. Desa pointed that organic debris<br />
within the sediments is decomposed by a complex sequence called<br />
methanogenesis into methane by bacteria in an anoxic environment.<br />
Decomposition takes place either by acetate fermentation or by the reduction<br />
of carbon dioxide. Hydrocarbons, including methane, are formed in the<br />
thermogenic process by thermal cracking of organically derived materials.<br />
Dr. Desa indicated that this generally occurs at depths greater than 2<br />
kilometres in sedimentary basins where temperatures are in excess of 100°<br />
centigrade. He also pointed out that thermogenic methane might also be<br />
formed by thermal degradation of oil at even greater depths and by<br />
maturation of coal.<br />
On prospecting and exploration of submarine methane hydrates, Dr.<br />
Desa states that while their presence is detected in drill cores, over large areas<br />
gas hydrates can be detected by using acoustical methods such as seismic<br />
reflection profiles. He mentioned that chlorinity anomalies in pore water,<br />
pore water redox levels, sediment grain size, carbon isotope signatures, and<br />
benthic biomass are all proxies that can be used in prospecting for gas<br />
hydrates. He also said that pockmarks or gas-escape features of the seafloor<br />
are another proxy that can be used in prospecting for gas hydrates. Dr. Desa<br />
mentioned that such information is acquired from high-resolution acoustic<br />
investigations (side scan imagery, shallow sub bottom profiling). He also<br />
mentioned that for the study of any proxies, surficial and shallow sub-surficial<br />
sediment samplers are required. An advanced technique that he mentioned is<br />
through specially designed pressure core samplers (PCS) within which gas<br />
samples can be stored up to minus eighty degrees (-80°C) for later analysis.<br />
INTERNATIONAL SEABED AUTHORITY 54
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