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| Author | : Mikhail Mikhailovich Zykov |
| Publisher | : |
| Total Pages | : |
| Release | : 2006 |
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| ISBN | : |
| Author | : |
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| Total Pages | : |
| Release | : 2006 |
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This dissertation presents results from a complex seismic study using Ocean Bottom Seismometers (OBS) conducted at a site of deep sea gas hydrate occurrence. The site is located on the accretionary margin of the northern Cascadia subduction zone offshore Vancouver Island. Canada. The major objectives for this study were the construction of a 3-D velocity model around the Bullseye vent zone by the means of travel time inversion tomography and the analysis of the amplitude data for reflections from the water-sediment interface and the bottom simulating reflector (BSR). Secondary objectives included the integration of the results from this study with previous knowledge about the vent zone for further clarification of its structure and evolution. The OBS seismic data set consisted of 22 parallel lines at 200 in spacing with three perpendicular crossing lines recorded on five OBS stations. Multichannel and single channel conventional seismic data along these lines were also acquired. The OBS experiment geometry required corrections for the coordinates of sources and receivers initially obtained in the field. A new comprehensive source and receiver localization technique was developed for the case of stationary hydrophones and multiple seismic lines. The horizontal size of the created 3-D velocity model is 3 km x 2.7 km. The modelled volume is limited by the seafloor at the top and by the BSR at the bottom. The size of a grid cell is 50 m x 50 m x 20 m. The uncertainty for the velocity value of individual cells was as low as 20 m/s. although the resolution of the model was reduced by the sparse receiver geometry. The inversion results indicate a fairly uniform velocity field around and inside the vent zone. Velocities are nearly equal to values expected for sediments containing no hydrate, which supports the idea that the bulk concentrations of gas hydrates are low at the site. The largest velocity anomaly with an amplitude of +25 m/s is spatially associated with the limi.
| Author | : Timothy S. Collett |
| Publisher | : AAPG |
| Total Pages | : 710 |
| Release | : 2010-01-14 |
| Genre | : Science |
| ISBN | : 0891813705 |
Hardcover plus CD
| Author | : Jürgen Mienert |
| Publisher | : Springer Nature |
| Total Pages | : 515 |
| Release | : 2022-01-01 |
| Genre | : Science |
| ISBN | : 3030811867 |
This world atlas presents a comprehensive overview of the gas-hydrate systems of our planet with contributions from esteemed international researchers from academia, governmental institutions and hydrocarbon industries. The book illustrates, describes and discusses gas hydrate systems, their geophysical evidence and their future prospects for climate change and continental margin geohazards from passive to active margins. This includes passive volcanic to non-volcanic margins including glaciated and non-glaciated margins from high to low latitudes. Shallow submarine gas hydrates allow a glimpse into the past from the Last Glacial Maximum (LGM) to modern environmental conditions to predict potential changes in future stability conditions while deep submarine gas hydrates remained more stable. This demonstrates their potential for rapid reactions for some gas hydrate provinces to a warming world, as well as helping to identify future prospects for environmental research. Three-dimensional and high-resolution seismic imaging technologies provide new insights into fluid flow systems in continental margins, enabling the identification of gas and gas escape routes to the seabed within gas hydrate environments, where seabed habitats may flourish. The volume contains a method section detailing the seismic imaging and logging while drilling techniques used to characterize gas hydrates and related dynamic processes in the sub seabed. This book is unique, as it goes well beyond the geophysical monograph series of natural gas hydrates and textbooks on marine geophysics. It also emphasizes the potential for gas hydrate research across a variety of disciplines. Observations of bottom simulating reflectors (BSRs) in 2D and 3D seismic reflection data combined with velocity analysis, electromagnetic investigations and gas-hydrate stability zone (GHSZ) modelling, provide the necessary insights for academic interests and hydrocarbon industries to understand the potential extent and volume of gas hydrates in a wide range of tectonic settings of continental margins. Gas hydrates control the largest and most dynamic reservoir of global carbon. Especially 4D, 3D seismic but also 2D seismic data provide compelling sub-seabed images of their dynamical behavior. Sub-seabed imaging techniques increase our understanding of the controlling mechanisms for the distribution and migration of gas before it enters the gas-hydrate stability zone. As methane hydrate stability depends mainly on pressure, temperature, gas composition and pore water chemistry, gas hydrates are usually found in ocean margin settings where water depth is more than 300 m and gas migrates upward from deeper geological formations. This highly dynamic environment may precondition the stability of continental slopes as evidenced by geohazards and gas expelled from the sea floor. This book provides new insights into variations in the character and existence of gas hydrates and BSRs in various geological environments, as well as their dynamics. The potentially dynamic behavior of this natural carbon system in a warming world, its current and future impacts on a variety of Earth environments can now be adequately evaluated by using the information provided in the world atlas. This book is relevant for students, researchers, governmental agencies and oil and gas professionals. Some familiarity with seismic data and some basic understanding of geology and tectonics are recommended.
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| Publisher | : |
| Total Pages | : 846 |
| Release | : 2006 |
| Genre | : Dissertations, Academic |
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| Author | : Michael D. Max |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 114 |
| Release | : 2013-10-11 |
| Genre | : Technology & Engineering |
| ISBN | : 3319025082 |
The book is an up-to-date basic reference for natural gas hydrate (NGH) in the Arctic Ocean. Geographical, geological, environmental, energy, new technology, and regulatory matters are discussed. The book should be of interest to general readers and scientists and students as well as industry and government agencies concerned with energy and ocean management. NGH is a solid crystalline material that compresses gas by about a factor of about 164 during crystallization from natural gas (mainly methane) - rich pore waters over time. NGH displaces water and may form large concentrations in sediment pore space. Its formation introduces changes in the geotechnical character of host sediment that allows it to be distinguished by seismic and electric exploration methods. The chemical reaction that forms NGH from gas and water molecules is highly reversible, which allows controlled conversion of the NGH to its constituent gas and water. This can be achieved rapidly by one of a number of processes including heating, depressurization, inhibitor injection, dissolution, and molecular replacement. The produced gas has the potential to make NGH a valuable unconventional natural gas resource, and perhaps the largest on earth. Estimates for NGH distribution, concentration, economic targets, and volumes in the Arctic Ocean have been carried out by restricting the economic target to deepwater turbidite sands, which are also sediment hosts for more deeply buried conventional hydrocarbon deposits. Resource base estimates are based on NGH petroleum system analysis approach using industry-standard parameters along with analogs from three relatively well known examples (Nankai-Japan, Gulf of Mexico-United States, and Arctic permafrost hydrate). Drilling data has substantiated new geotechnical-level seismic analysis techniques for estimating not just the presence of NGH but prospect volumes. In addition to a volumetric estimate for NGH having economic potential, a sedimentary depositional model is proposed to aid exploration in the five different regions around the deep central Arctic Ocean basin. Related topics are also discussed. Transport and logistics for NGH may also be applicable for stranded conventional gas and oil deposits. Arising from a discussion of new technology and methodologies that could be applied to developing NGH, suggestions are made for the lowering of exploration and capital expenses that could make NGH competitive on a produced cost basis. The basis for the extraordinarily low environmental risk for exploration and production of NGH is discussed, especially with respect to the environmentally fragile Arctic region. It is suggested that because of the low environmental risk, special regulations could be written that would provide a framework for very low cost and safe development.
| Author | : Emily Megan Graham |
| Publisher | : |
| Total Pages | : 174 |
| Release | : 2011 |
| Genre | : |
| ISBN | : |
Hydrate Ridge is a peanut shape bathymetric high located about 80 km west of Newport, Oregon on the Pacific continental margin, within the Cascadia subduction zone's accretionary wedge. The ridge's two topographic highs (S. and N. Hydrate Ridge) are characterized by gas vents and seeps that were observed with previous ODP initiatives. In 2008, we acquired a 3D seismic reflection data set using the P-Cable acquisition system to characterize the subsurface fluid migration pathways that feed the seafloor vent at S. Hydrate Ridge. The new high-resolution data reveal a complex 3D structure of localized faulting within the gas hydrate stability zone (GHSZ). We interpret two groups of fault-related migration pathways. The first group is defined by regularly- and widely-spaced (100-150 m) faults that extend greater than 300ms TWT (~ 250 m) below seafloor and coincide with the regional thrust fault orientations of the Oregon margin. The deep extent of these faults makes them potential conduits for deeply sourced methane and may include thermogenic methane, which was found with shallow drilling during ODP Leg 204. As a fluid pathway these faults may complement the previously identified sand-rich, gas-filled stratigraphic horizon, Horizon A, which is a major gas migration pathway to the summit of S. Hydrate Ridge. The second group of faults is characterized by irregularly but closely spaced (~ 50 m), shallow fractures (extending
| Author | : Claire A. Currie |
| Publisher | : |
| Total Pages | : 106 |
| Release | : 1999 |
| Genre | : Natural gas |
| ISBN | : |
| Author | : Manuel Enrique Pardo Echarte |
| Publisher | : Springer |
| Total Pages | : 72 |
| Release | : 2018-03-17 |
| Genre | : Science |
| ISBN | : 3319771558 |
This book provides an overview of the major changes induced by hydrocarbons (HCs) affecting rocks and surface sediments and their implications for non-seismic exploration methods, particularly for marine territories near Cuba. It examines the use of a digital elevation model (DEM) at 90x90m resolution for the detection of subtle, positive geomorphic anomalies related to hydrocarbon microseepage (vertical migration) on possible oil and gas targets. The results support the conclusion that the DEM data provides a low cost and fast offshore oil and gas preliminary exploration strategy. This data is useful serving to focus prospective areas with supplementary unconventional methods such as magnetic-induced polarization (MIP), useful to propose more expensive volumes for detailed 2D–3D seismic surveys.
| Author | : Adam John Cherrett |
| Publisher | : |
| Total Pages | : |
| Release | : 2001 |
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