AndreaBozzo/ceres-open-data-index huggingface dataset:
Overview of Gas Hydrate Research at the Mallik Field in the Mackenzie Delta, Northwest Territories, Canada

The Mallik gas hydrate field, located at the northeastern edge of Canada's Mackenzie Delta, occurs within a sequence of Tertiary sediments in an area underlain by over 600m of permafrost. With data available from the original discovery well in 1971/72, and a scientific research well program in 1998, gas hydrate occurrences have been well documented. Quantitative well log determinations and core studies reveal at least 10 discrete gas hydrate layers from 890 m to 1106 m depth, exceeding 110 m in total thickness. High gas hydrate saturation values, which in some cases exceed 80% of the pore volume, establish the Mallik gas hydrate field as one of the most concentrated gas hydrate reservoirs in the world. Beginning in December 2001 and continuing to March 2002, a production research well program was completed that include drilling of a 1200 m deep main production research well and two nearby science observation wells. The research program represents a collaboration between the Geological Survey of Canada, the Japan National Oil Corporation, GeoForschungsZentrum Potsdam, the U.S. Geological Survey, the U.S. Department of Energy and the Gas Authority of India Ltd/Oil and Natural Gas Corporation Ltd. The Geological Survey of Canada is coordinating the science program for the project and JAPEX Canada Ltd is the designated operator for the fieldwork. Primary objectives of the Mallik 2002 production research well program are to advance fundamental geological, geophysical and geochemical studies of the Mallik gas hydrate field and to undertake advanced production testing of a concentrated gas hydrate reservoir. Full-scale field experiments will monitor the physical behavior of the hydrate deposits in response to depressurization and thermal stimulation. The observation wells will facilitate cross-hole tomography experiments (before and after production testing) as well as long term monitoring of in situ formation conditions. A wide ranging science and engineering research program will include collection of gas-hydrate-bearing core samples and downhole geophysical logging. Laboratory and modeling studies undertaken during the field program, and subsequently as part of a post-field research program will document the sedimentology, physical/petrophysical properties, geochemistry, geophysics, reservoir characteristics and production behavior of the Mallik gas hydrate accumulation.

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Methane Hydrate Issues -- Resource Assessment

The estimated amount of gas in the hydrate accumulations of the world greatly exceeds the volume of known conventional gas reserves. However, the role that gas hydrates will play in contributing to the world's energy requirements will depend ultimately on the availability of sufficient gas hydrate resources and the ?cost? to extract them. Yet considerable uncertainty and disagreement prevails concerning the world's gas hydrate resources. Gas hydrates occur in sedimentary deposits under conditions of pressure and temperature present in permafrost regions and beneath the sea in outer continental margins. The combined information from Arctic gas-hydrate studies shows that, in permafrost regions, gas hydrates may exist at subsurface depths ranging from about 130 to 2,000 m. The presence of gas hydrates in offshore continental margins has been inferred mainly from anomalous seismic reflectors known as bottom-simulating reflectors, that have been mapped at depths below the sea floor ranging from about 100 to 1,100 m. Current estimates of the amount of gas in the world's marine and permafrost gas hydrate accumulations are in rough accord at about 20,000 trillion cubic meters. Gas hydrate as an energy commodity is often grouped with other unconventional hydrocarbon resources. In most cases, the evolution of a non-producible unconventional resource to a producible energy resource has relied on significant capital investment and technology development. To evaluate the energy resource potential of gas hydrates, will also require the support of sustained research and development programs. Despite the fact that relatively little is known about the ultimate resource potential of natural gas hydrates, it is certain that gas hydrates are a vast storehouse of natural gas and significant technical challenges need to be met before this enormous resource can be considered an economically producible reserve.

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Methane Hydrate Formation and Stability along the Texas-Louisiana Shelf, in the Gulf of Mexico

Work has been conducted on the Texas-Louisiana Shelf, Norwegian-Greenland Sea, and Cascadia Margin to compare the relative input of biogenic and thermogenic methane on hydrate formation, stability and lattice saturation. Hydrate composition and carbon isotope analysis of organic sediment, bacterial biomarkers and methane shows a wide range of sources between these coastal regions. In the Norwegian-Greenland Sea the hydrates contained 99.5% methane, while on the Texas-Louisiana Shelf the values ranged from 30% to 78%. In the Norwegian-Greenland Sea and Cascadia Margin biogenic signatures, averaging ?63.5 ppt, were measured in methane from the hydrates. Data from the Texas-Louisiana Shelf suggests that there is mixture between the sources of methane. Methane stable carbon isotope ratios range from ? 48.5 to ?33.0 ppt, with the lower values suggesting that methane is from bacterial activity. Radio carbon isotope analysis on methane from hydrates in the Cascadia Margin and Texas-Louisiana Shelf were isotopically depleted suggesting a strong influence of thermogenic carbon or vertical migration of old biogenic carbon. In addition to the analysis of surface hydrates on the Texas-Louisiana Shelf, work has addressed the flux of methane into the water column. Stable carbon isotope analysis suggests ocean floor methane contributes a significant portion of the total carbon that is assimilated by bacterioplankton. In a subsequent study, the analysis of methane assimilation by bacteria in terms of a carbon concentration budget does not thoroughly support methane contribution to bacterial biomass. An alternate analytical approach is an energetic calculation as a function of methane availability, related to heterotrophic bacterial production. Application of this approach was conducted over a methane hydrate rich region on the Texas-Louisiana Shelf. Methane concentrations through the water column over a series of 20 submarine dives show a high concentration of methane in the water column, toward the ocean floor. Analysis of methane turnover, in incubation experiments, during this period indicate potential for a rapid cycling of the methane pools. The energy in the dissolved methane relative to the bacterial production in vertical profiles, demonstrates occasions that methane can support a dominant fraction of the carbon cycle.

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Role of Methane Hydrates in Climate Change: Compelling evidence and debate

The methane hydrate reservoir has largely been ignored as a component of climate change in the Quaternary. However there is growing acceptance that changes in the methane hydrate reservoir played an important role in climate change prior to the Quaternary. The origin of several brief episodes of global warming has been linked with massive dissociation of hydrates and CH4 transfer into the ocean/atmosphere as recorded by large, negative carbon isotope excursions. The remarkable similarity of atmospheric methane (CH4) and temperature variations recorded in ice cores suggests that CH4 played an important role in late Quaternary climate change. We have proposed that the late Quaternary (last 800 kyr) was also a time of significant instability of the methane hydrate reservoir and associated episodic greenhouse climatic forcing due to transfer of CH4 to the atmosphere (Kennett, Cannariato, Hendy and Behl, submitted). Unlike the prevailing interpretation that continental wetlands were the principal source for the rapid atmospheric CH4 increases during the late Quaternary, we suggest a marine sedimentary methane hydrate source. Negligible wetland ecosystems existed during the last glacial episode as a result of global aridity, low sea level, incised, well flushed river systems and low water tables. Wetland ecosystems were insufficiently developed during the last glacial episode to account for the rapid atmospheric CH4 increases during glacial and stadial terminations recorded in polar ice cores. The large, modern wetland ecosystems (peatlands, tropical floodplains, and coastal wetlands) developed almost exclusively during the Holocene, well after the rapid atmospheric CH4 increases during the last glacial termination.

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Marine Gas Hydrates on the Northern Cascadia Margin

On the northern Cascadia margin there have been extensive geophysical and geological studies, and Ocean Drilling Project (ODP) drilling that constrain the occurrence, distribution, and concentration of gas hydrate and underlying free gas beneath the continental slope. On this margin there is a large clastic accretionary sedimentary prism, the most common environment for high concentrations of marine gas hydrates. Most information on the gas hydrate has come from a wide range of seismic surveys, including multi-frequency surface seismic surveys, the NRL DTAGS deep towed seismic system, and ocean bottom seismographs. The data have allowed mapping the area of the characteristic bottom-simulating reflector (BSR), determining the depth distribution of hydrate and underlying free gas, and the geological controls of hydrate formation. BSRs are evident beneath about half of the mid-continental slope at a sub-bottom depth of about 250 m. Special seismic studies include BSR reflection coefficients, the frequency dependence of the BSR amplitude, BSR amplitude-versus-offset (AVO), and full waveform inversions. Additional information on hydrate concentration is provided by electrical resistivity profiling, and measurements of seafloor compliance. Heat flow surveys have mapped the thermal regime that controls the depth to which gas hydrate is stable. The seafloor expressions of focused methane expulsion have been studied by piston core sampling and by the remotely operated submersible, ROPOS. Ocean Drilling Program Leg 146 drilled through the gas hydrate on the mid-continental slope and a reference hole in the adjacent deep sea Cascadia basin. Downhole geophysical logs and core analyses have constrained the concentrations of hydrate and free gas at the drill sites, and provided calibration of the regional geophysical data. In the region of the ODP site, there is a regional layer 50-100 m thick above BSR with concentration of disseminated hydrate in pore spaces that represent a very large amount of methane. In a few areas there are localized chimneys or channels especially well imaged by the DTAGS seismic data. They may contain a smaller total amount of methane but often have high concentration and massive hydrate. From both geophysical and borehole data the disseminated concentration is 20-30% of the pore space (10-15% of total volume), with an underlying 10-20 m layer of less than 1% free gas. The electrical data indicate that there may be significant hydrate concentrations where there are no BSRs. Over the chimney structures, coring has recovered massive gas hydrate, ROPOS submersible surveys show seafloor carbonates and cool vent organisms, and oceanographic data show a rising plume in the overlying ocean. These structures thus may focus upward fluid and methane transport. In an adjacent area several tonnes of massive gas hydrate were recovered from such a structure by a fishing dragger in experimental fishery.

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Development of Improved Oil Field Waste Injection Disposal Techniques

Slurry Fracture Injection (SFI) is a waste disposal technology in which petroleum exploration and production wastes, such as produced sand, drill cuttings, tank bottoms, and pit sludge are mixed with water into a slurry and injected into deep unconsolidated sandstone formations above fracturing pressure. The solids are permanently emplaced within hydraulic fractures generated during the pumping process, and the carrying fluid subsequently drains into the high permeability formation. The mechanics governing the fracturing of unconsolidated sandstone formations remain poorly understood, and as a result there are few guidelines available to optimize the SFI process.

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Migration of methane gas through the hydrate stability zone in a low-flux hydrate province

New high-resolution seismic data show clear evidence for upward injection of methane gas well into the hydrate stability zone at the stable, low-methane-flux Blake Ridge crest. This movement of gaseous methane, through a thermo-dynamic regime where it should be trapped as hydrate, suggests that dynamic migrations of gas play an important role in the interaction of sub seafloor methane with the ocean. In the study area, none of the seismic amplitude anomalies that provide evidence for gas migration reaches the seafloor; instead they terminate at the base of a highly reflective, unfaulted capping layer. Seismic inversions of anomalous regions show (1) increased velocities beneath the hydrate stability zone, suggesting less gas, and (2) increased velocities within the hydrate stability zone associated with observed low-amplitude chimneys and bright spots, indicating increased hydrate concentrations. These observations and analyses indicate that methane migrates upward as free gas hundreds of meters into the hydrate stability zone before forming hydrate. The observations strongly imply that given appropriate permeable pathways, free gas can escape into the ocean. Even in a low-flux environment, the hydrate stability zone is not an impermeable barrier to free-gas migration.

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Proceedings of the Methane Hydrates Interagency R&D Conference

The Methane Hydrates Interagency R&D Conference, held March 20-22, 2002, in  Washington, D.C. was a collaborative effort of five federal agencies to present the  results of, and future plans for, methane hydrate research. Topics presented included assessment of the scale at which hydrates occur; discussion on the connections among hydrates, global climate change, the world's oceans, and newly discovered chemosynthetic life forms; and discussion of the potential production of methane from hydrates. Participating federal agencies were:                                                                                        -Department of Energy (DOE) Office of Fossil Energy (FE) and National Energy Technology Laboratory (NETL) through the Strategic Center for Natural Gas (SCNG,2292 ); - Department of Commerce (DOE) National Oceanic and Atmospheric Administration (NOAA,2292 ); -Department of Defense (DoD) Naval Research Laboratory (NRL,2292 ); - Department of Interior (DOI) Minerals Management Service (MMS) -Department of Interior (DOI) U.S. Geological Survey (USGS,2292 ); and - National Science Foundation (NSF).

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Methane Hydrate Research at NRL

Investigations are underway at NRL on oceanic methane hydrates to understand seafloor instabilities, geoacoustic anomalies of the ocean sediment using high resolution deep towed multichannel seismic system, fine scale hydrate concentration and structure using in-situ NMR and X-ray diffraction, and carbon isotope analysis to distinguish biogenic and thermogenic methane. additionally, NRL has established active collaborations with USGS, NETL, MBARI, the Geological Survey of Canada, University of Hawaii, Florida State University, Texas A&M University, Japan National Oil Corp., and University of Bergan. An overview of these topics will be discussed.

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Transmission of CO2 and Energy

This study provides a spread-sheet based model for initial assessment of the costs and performance of CO2 and energy transmission systems. The model covers pipeline transmissions of CO2, natural gas, hydrogen, methanol, and distillate oil, and AC and HVDC transmission of electricity. It can be used to calculate the costs and performance of onshore and offshore pipelines and to asses the sensitivity to a wide range of factors, such as flowrate, pipeline diameter, pressure, terrain, and country. It can also be used to asses different pipeline configurations, such as dedicated single pipelines or pipeline grids including trunk lines.

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Development of Multi-Station Borehole Seismic Receivers

The bandwidth associated with conventional surface-seismic and VSP (vertical seismic profiling) techniques for imaging deep petroleum reservoirs is typically less than 150 Hz. With the advent of cross-well seismic techniques, the bandwidth is potentially increased well beyond 150 Hz due to the shorter propagation paths and the improved seismic coupling at depth. While conventional geophones are already the appropriate sensors for low-frequency, surface seismic applications, their performance degrade at the cross-well frequencies. The presence of tool resonance in the conventional well-locked geophones also results in distortion of the seismic signal at higher frequencies. To take advantage of the high-resolution capabilities of cross-well imaging, Sandia National Laboratory, Albuquerque, NM initiated research to develop high-resolution receivers using high-sensitivity, broad frequency, three component triaxial accelerometers. A single-station seismic receiver with advanced solid-state accelerometer having both high sensitivity and broad frequency response was fabricated and tested and subsequently, a 5-station multi-receiver array was developed and married to a fiber-optic wireline that allowed analysis of subsurface data in almost real time. The ability of the tool to withstand high borehole pressure and temperature conditions is important design features of the new tool. Extensive field tests conducted at the Texaco Humble Field Site in Houston, TX conclusively demonstrated the signal-enhancement characteristics (increased bandwidth and signal-to-noise-ratio) of the new tool. The accelerometer was shown to offer 25 dB signal-to-noise enhancement at 1000 Hz relative to the buried geophone. This major hardware development, done in close working relationship with OYO Geospace, Houston, Texas was later licensed and offered for sale.

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Biological communities at Blake Ridge seeps: Faunal distributions and trophic interactions

Recent reconnaissance of the Blake Ridge Diapir using the submersible Alvin resulted in mapping and sampling of dense invertebrate communities associated with the subsurface methane hydrates. The geographic location of the Blake Ridge methane seeps raises questions about the biogeographical affinities of its fauna. The closest known, deep seep sites are those of the Barbados region to the southeast and of the Florida Escarpment, on the opposite side of the Florida. A primary objective of the field program was to obtain quantitative samples that will allow us to make robust comparisons of species lists among these seep sites to determine the degree of endemicity of their faunas and thus to provide a preliminary assessment of their sensitivity to habitat degradation.

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Anatomy of a Gas Hydrate Province: Linking Physics and Biology on the Blake Ridge

The Blake Ridge is one of the largest and best-characterization of the marine gas hydrate provinces within the US Exclusive Economic Zone.  However, the lack of commercial exploration on the Blake Ridge, coupled with the largely disseminated nature of the hydrate deposits, means that this region is often overlooked in assessments of geohazard or resource potential on US continental margins. In fact, hydrates in the sediments of the Blake Ridge and nearby regions are associated with both natural hazards (e.g. submarine slope failures) and large quantities of methane.  For these and other reasons, studies of the Blake Ridge remain as relevant as ever for advancing our understanding of methane hydrates. Research on the Blake Ridge continues to yield fundamental insights into the dynamics of gas hydrate reservoirs, the interaction of hydrates and the ocean-atmosphere system, and the physical, chemical, and biological processes that control concentration and accumulation of hydrates.

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Recent seismic results from the Blake Ridge Hydrate Province: Implications for direct detection, gas injection, and methane escape

A deeper understanding of marine methane hydrate systems requires progress on several key issues, including: (1) the global and local distribution and concentrations of hydrate and associated free gas, (2) the sites, rates, and mechanisms of interaction between the Earth's hydrate reservoir and the global carbon cycle, and (3) the dynamics of hydrate systems. Addressing these issues requires improved methods of remotely detecting and quantifying methane hydrate and gas using seismic reflection data. We present new seismic reflection data from the Blake Ridge hydrate province, offshore South Carolina, that yield new insights on both hydrate processes and seismic detection of hydrate. The Blake Ridge is an excellent field laboratory to study hydrate processes, largely because the relatively simple tectonic setting and uniform lithologies provide a virtual tabula rasa against which seismic anomalies can be confidently interpreted in terms of gas and hydrate. A large array of background knowledge exists on the Blake Ridge, from numerous seismic, drilling, coring, and submersible studies. Sedimentary biological, and physical processes produce a wide array of methane flux environments within a relatively well-understood We acquired long-offset (6000 m), high-resolution (6.25 m CMP spacing) seismic reflection data in Fall 2000 on the Blake Ridge in a project jointly sponsored by NSF and DOE. These data provide remarkably clear images of the entire hydrate and free gas zone, up to depths of 1000 mbsl. Examples of direct seismic detection of hydrate within the hydrate stability zone include (1) ?bright spots? from layers of concentrated hydrate (up to 70% of porosity), (2)cross-cutting paleo-BSR reflections formed after erosional events, and (3) a lens of amplitude ?blanking? that has been confirmed as a high-velocity layer that likely contains elevated concentrations of hydrate (~30% of porosity). The free gas zone on the Blake Ridge is surprisingly dynamic, with numerous chimneys through which gas can migrate hundreds of meters into the hydrate stability zone. Large quantities (0.6 Gt) of methane gas have apparently escaped through a large depression on the ridge crest that represents a large sediment wave field.

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