224 Matching Results

Search Results

Advanced search parameters have been applied.

Feasibility of monitoring gas hydrate production with time-lapse VSP

Description: In this work we begin to examine the feasibility of using time-lapse seismic methods-specifically the vertical seismic profiling (VSP) method-for monitoring changes in hydrate accumulations that are predicted to occur during production of natural gas.
Date: November 1, 2009
Creator: Kowalsky, M.B.; Nakagawa, S. & Moridis, G.J.
Partner: UNT Libraries Government Documents Department

Numerical, Laboratory And Field Studiesof Gas Production FromNatural Hydrate Accumulations in Geologic Media

Description: We discuss the range of activities at Lawrence BerkeleyNational Laboratory in support of gas production from natural hydrates.Investigations of production from the various classes of hydrate depositsby numerical simulation indicate their significant promise as potentialenergy sources. Laboratory studies are coordinated with the numericalstudies and are designed to address knowledge gaps that are important tothe prediction of gas production. Our involvement in field tests is alsobriefly discussed.
Date: October 17, 2006
Creator: Moridis, George J.; Kneafsey, Timothy J.; Kowalsky, Michael & Reagan, Matthew
Partner: UNT Libraries Government Documents Department

Laboratory measurements of compressional and shear wave speeds through methane hydrate

Description: Simultaneous measurements of compressional and shear wave speeds through polycrystalline methane hydrate have been made. Methane hydrate, grown directly in a wave speed measurement chamber, was uniaxially compacted to a final porosity below 2%. At 277 K, the compacted material's compressional wave speed was 3650 {+-} 50 m/s. The shear wave speed, measured simultaneously, was 1890 {+-} 30 m/s. From these wave speed measurements, we derive Vp/Vs, Poisson's Ratio, bulk, shear and Young's moduli.
Date: October 25, 1999
Creator: Durham, W B; Waite, WF; Pinkston, J C; Stern, L A; Kirby, S H; Helgerud, M B et al.
Partner: UNT Libraries Government Documents Department

Toward Production From Gas Hydrates: Current Status, Assessment of Resources, and Simulation-Based Evaluationof Technology and Potential

Description: Gas hydrates are a vast energy resource with global distribution in the permafrost and in the oceans. Even if conservative estimates are considered and only a small fraction is recoverable, the sheer size of the resource is so large that it demands evaluation as a potential energy source. In this review paper, we discuss the distribution of natural gas hydrate accumulations, the status of the primary international R&D programs, and the remaining science and technological challenges facing commercialization of production. After a brief examination of gas hydrate accumulations that are well characterized and appear to be models for future development and gas production, we analyze the role of numerical simulation in the assessment of the hydrate production potential, identify the data needs for reliable predictions, evaluate the status of knowledge with regard to these needs, discuss knowledge gaps and their impact, and reach the conclusion that the numerical simulation capabilities are quite advanced and that the related gaps are either not significant or are being addressed. We review the current body of literature relevant to potential productivity from different types of gas hydrate deposits, and determine that there are consistent indications of a large production potential at high rates over long periods from a wide variety of hydrate deposits. Finally, we identify (a) features, conditions, geology and techniques that are desirable in potential production targets, (b) methods to maximize production, and (c) some of the conditions and characteristics that render certain gas hydrate deposits undesirable for production.
Date: February 12, 2008
Creator: Reagan, Matthew; Moridis, George J.; Collett, Timothy; Boswell, Ray; Kurihara, M.; Reagan, Matthew T. et al.
Partner: UNT Libraries Government Documents Department

X-ray Scanner for ODP Leg 204: Drilling Gas Hydrates on Hydrate Ridge, Cascadia Continental Margin

Description: An x-ray scanner was designed and fabricated at Lawrence Berkeley National Laboratory to provide high speed acquisition of x-ray images of sediment cores collected on the Ocean Drilling Program (ODP) Leg 204: Drilling Gas Hydrates On Hydrate Ridge, Cascadia Continental Margin. This report discusses the design and fabrication of the instrument, detailing novel features that help reduce the weight and increase the portability of the instrument. Sample x-ray images are included. The x-ray scanner was transferred to scientific drilling vessel, the JOIDES Resolution, by the resupply ship Mauna Loa, out of Coos Bay, Oregon on July 25. ODP technicians were trained in the instruments operation. The availability of the x-ray scanner at the drilling site allows real-time imaging of cores containing methane hydrate immediately after retrieval. Thus, imaging experiments on cores can yield information on the distribution and quantity of methane hydrates. Performing these measurements at the location of core collection eliminates the need for high pressures or low temperature core handling while the cores are stored and transported to a remote imaging laboratory.
Date: August 8, 2002
Creator: Freifeld, Barry; Kneafsey, Tim; Pruess, Jacob; Reiter, Paul & Tomutsa, Liviu
Partner: UNT Libraries Government Documents Department

Laboratory measurements on core-scale sediment/hydrate samples topredice reservoir behavior

Description: Measurements on hydrate-bearing laboratory and field samplesare necessary in order to provide realistic bounds on parameters used innumerically modeling the production of natural gas from hydrate-bearingreservoirs. The needed parameters include thermal conductivity,permeability, relative permeability-saturation(s) relationships, andcapillary pressure-saturation(s) relationships. We have developed atechnique to make hydrate-bearing samples ranging in scale from coreplug-size to core-size in the laboratory to facilitate making thesemeasurements. In addition to pressure and temperature measurements, weuse x-ray computed tomography scanning to provide high-resolution dataproviding insights on processes occurring in our samples. Several methodsare available to make gas hydrates in the laboratory, and we expect thatthe method used to make the hydrate will impact the behavior of thehydrate sample, and the parameters measured.
Date: November 2, 2005
Creator: Kneafsey, Timothy J.; Seol, Yongkoo; Moridis, George J.; Tomutsa,Liviu & Freifeld, Barry M.
Partner: UNT Libraries Government Documents Department

In-Situ Sampling and Characterization of Naturally Occurring Marine Methane Hydrate Using the D/V JOIDES Resolution

Description: The primary accomplishments of the JOI Cooperative Agreement with DOE/NETL in this quarter were that: (1) Frank Rack, Anne Trehu, and Tim Collett presented preliminary results and operational outcomes of ODP Leg 204 at the American Association of Petroleum Geologists annual meeting in Salt Lake City, UT; (2) several Leg 204 scientists participated in special hydrate sessions at the international EGS/AGU/EUG meeting in Nice, France and presented initial science results from the cruise, which included outcomes arising from this cooperative agreement; and, (3) postcruise evaluation of the data, tools and measurement systems that were used during ODP Leg 204 continued in the preparation of deliverables under this agreement. At the EGS/EUG/AGU meeting in Nice, France in April, Leg 204 Co-chiefs Anne Trehu and Gerhard Bohrmann, as well as ODP scientists Charlie Paull, Erwin Suess, and Jim Kennett, participated in a press conference on hydrates. The well-attended press conference entitled ''Gas Hydrates: Free methane found and controversy over the 'hydrate gun''' led to stories in Nature on-line and BBC radio, among others. There were six (6) oral and fifteen (15) poster presentations on ODP Leg 204 hydrate science at the EGS/AGU/EUG Meeting in Nice, France on April 6-11, 2003. This was a very strong showing at a meeting just over six month following the completion of the drilling cruise and highlighted many of the results of the leg, including the results obtained with instruments and equipment funded under this cooperative agreement. At the AAPG annual meeting in Salt Lake City, UT on May 11-14, 2003, Anne Trehu gave an oral presentation about the scientific results of Leg 204, and Frank Rack presented a poster outlining the operational and technical accomplishments. Work continued on analyzing data collected during ODP Leg 204 and preparing reports on the outcomes of Phase 1 projects as ...
Date: June 30, 2003
Creator: Rack, Frank & Party, ODP Leg 204 Shipboard Scientific
Partner: UNT Libraries Government Documents Department

DOE THREE-DIMENSIONAL STRUCTURE AND PHYSICAL PROPERTIES OF A METHANE HYDRATE DEPOSIT AND GAS RESERVOIR, BLAKE RIDGE

Description: This report contains a summary of work conducted and results produced under the auspices of award DE-FC26-00NT40921, ''DOE Three-Dimensional Structure and Physical Properties of a Methane Hydrate Deposit and Gas Reservoir, Blake Ridge.'' This award supported acquisition, processing, and interpretation of two- and three-dimensional seismic reflection data over a large methane hydrate reservoir on the Blake Ridge, offshore South Carolina. The work supported by this project has led to important new conclusions regarding (1) the use of seismic reflection data to directly detect methane hydrate, (2) the migration and possible escape of free gas through the hydrate stability zone, and (3) the mechanical controls on the maximum thickness of the free gas zone and gas escape.
Date: November 11, 2004
Creator: Holbrook, W. Steven
Partner: UNT Libraries Government Documents Department

GULF OF MEXICO SEAFLOOR STABILITY AND GAS HYDRATE MONITORING STATION PROJECT

Description: The gas hydrates research Consortium (HRC), established and administered at the University if Mississippi's Center for Marine Research and Environmental Technology (CMRET) has been active on many fronts in FY 03. Extension of the original contract through March 2004, has allowed completion of many projects that were incomplete at the end of the original project period due, primarily, to severe weather and difficulties in rescheduling test cruises. The primary objective of the Consortium, to design and emplace a remote sea floor station for the monitoring of gas hydrates in the Gulf of Mexico by the year 2005 remains intact. However, the possibility of levering HRC research off of the Joint Industries Program (JIP) became a possibility that has demanded reevaluation of some of the fundamental assumptions of the station format. These provisions are discussed in Appendix A. Landmark achievements of FY03 include: (1) Continuation of Consortium development with new researchers and additional areas of research contribution being incorporated into the project. During this period, NOAA's National Undersea Research Program's (NURP) National Institute for Undersea Science and Technology (NIUST) became a Consortium funding partner, joining DOE and Minerals Management Service (MMS); (2) Very successful annual and semiannual meetings in Oxford Mississippi in February and September, 2003; (3) Collection of piston cores from MC798 in support of the effort to evaluate the site for possible monitoring station installation; (4) Completion of the site evaluation effort including reports of all localities in the northern Gulf of Mexico where hydrates have been documented or are strongly suspected to exist on the sea floor or in the shallow subsurface; (5) Collection and preliminary evaluation of vent gases and core samples of hydrate from sites in Green Canyon and Mississippi Canyon, northern Gulf of Mexico; (6) Monitoring of gas activity on the sea floor, acoustically and ...
Date: November 1, 2004
Creator: Woolsey, J. Robert; McGee, Thomas M. & Buchannon, Robin C.
Partner: UNT Libraries Government Documents Department

The Use of Horizontal Wells in Gas Production from Hydrate Accumulations

Description: The amounts of hydrocarbon gases trapped in natural hydrate accumulations are enormous, leading to a recent interest in the evaluation of their potential as an energy source. Earlier studies have demonstrated that large volumes of gas can be readily produced at high rates for long times from gas hydrate accumulations by means of depressurization-induced dissociation, using conventional technology and vertical wells. The results of this numerical study indicate that the use of horizontal wells does not confer any practical advantages to gas production from Class 1 deposits. This is because of the large disparity in permeabilities between the hydrate layer (HL) and the underlying free gas zone, leading to a hydrate dissociation that proceeds in a horizontally dominant direction and is uniform along the length of the reservoir. When horizontal wells are placed near the base of the HL in Class 2 deposits, the delay in the evolution of a significant gas production rate outweighs their advantages, which include higher rates and the prevention of flow obstruction problems that often hamper the performance of vertical wells. Conversely, placement of a horizontal well near to top of the HL can lead to dramatic increases in gas production from Class 2 and Class 3 deposits over the corresponding production from vertical wells.
Date: April 15, 2008
Creator: Reagan, Matthew; Moridis, George J.; Reagan, Matthew T. & Zhang, Keni
Partner: UNT Libraries Government Documents Department

Contribution of oceanic gas hydrate dissociation to the formation of Arctic Ocean methane plumes

Description: Vast quantities of methane are trapped in oceanic hydrate deposits, and there is concern that a rise in the ocean temperature will induce dissociation of these hydrate accumulations, potentially releasing large amounts of carbon into the atmosphere. Because methane is a powerful greenhouse gas, such a release could have dramatic climatic consequences. The recent discovery of active methane gas venting along the landward limit of the gas hydrate stability zone (GHSZ) on the shallow continental slope (150 m - 400 m) west of Svalbard suggests that this process may already have begun, but the source of the methane has not yet been determined. This study performs 2-D simulations of hydrate dissociation in conditions representative of the Arctic Ocean margin to assess whether such hydrates could contribute to the observed gas release. The results show that shallow, low-saturation hydrate deposits, if subjected to recently observed or future predicted temperature changes at the seafloor, can release quantities of methane at the magnitudes similar to what has been observed, and that the releases will be localized near the landward limit of the GHSZ. Both gradual and rapid warming is simulated, along with a parametric sensitivity analysis, and localized gas release is observed for most of the cases. These results resemble the recently published observations and strongly suggest that hydrate dissociation and methane release as a result of climate change may be a real phenomenon, that it could occur on decadal timescales, and that it already may be occurring.
Date: June 1, 2011
Creator: Reagan, M.; Moridis, G.; Elliott, S. & Maltrud, M.
Partner: UNT Libraries Government Documents Department

Basin scale assessment of gas hydrate dissociation in response to climate change

Description: Paleooceanographic evidence has been used to postulate that methane from oceanic hydrates may have had a significant role in regulating climate. However, the behavior of contemporary oceanic methane hydrate deposits subjected to rapid temperature changes, like those now occurring in the arctic and those predicted under future climate change scenarios, has only recently been investigated. Field investigations have discovered substantial methane gas plumes exiting the seafloor along the Arctic Ocean margin, and the plumes appear at depths corresponding to the upper limit of a receding gas hydrate stability zone. It has been suggested that these plumes may be the first visible signs of the dissociation of shallow hydrate deposits due to ongoing climate change in the arctic. We simulate the release of methane from oceanic deposits, including the effects of fully-coupled heat transfer, fluid flow, hydrate dissociation, and other thermodynamic processes, for systems representative of segments of the Arctic Ocean margins. The modeling encompasses a range of shallow hydrate deposits from the landward limit of the hydrate stability zone down to water depths beyond the expected range of century-scale temperature changes. We impose temperature changes corresponding to predicted rates of climate change-related ocean warming and examine the possibility of hydrate dissociation and the release of methane. The assessment is performed at local-, regional-, and basin-scales. The simulation results are consistent with the hypothesis that dissociating shallow hydrates alone can result in significant methane fluxes at the seafloor. However, the methane release is likely to be confined to a narrow region of high dissociation susceptibility, defined by depth and temperature, and that any release will be continuous and controlled, rather than explosive. This modeling also establishes the first realistic bounds for methane release along the arctic continental shelf for potential hydrate dissociation scenarios, and ongoing work may help confirm whether climate ...
Date: July 1, 2011
Creator: Reagan, M.; Moridis, G.; Elliott, S.; Maltrud, M. & Cameron-Smith, P.
Partner: UNT Libraries Government Documents Department

Investigation of gas hydrate-bearing sandstone reservoirs at the "Mount Elbert" stratigraphic test well, Milne Point, Alaska

Description: In February 2007, the U.S. Department of Energy, BP Exploration (Alaska), Inc., and the U.S. Geological Survey conducted an extensive data collection effort at the "Mount Elbert #1" gas hydrates stratigraphic test well on the Alaska North Slope (ANS). The 22-day field program acquired significant gas hydrate-bearing reservoir data, including a full suite of open-hole well logs, over 500 feet of continuous core, and open-hole formation pressure response tests. Hole conditions, and therefore log data quality, were excellent due largely to the use of chilled oil-based drilling fluids. The logging program confirmed the existence of approximately 30 m of gashydrate saturated, fine-grained sand reservoir. Gas hydrate saturations were observed to range from 60% to 75% largely as a function of reservoir quality. Continuous wire-line coring operations (the first conducted on the ANS) achieved 85% recovery through 153 meters of section, providing more than 250 subsamples for analysis. The "Mount Elbert" data collection program culminated with open-hole tests of reservoir flow and pressure responses, as well as gas and water sample collection, using Schlumberger's Modular Formation Dynamics Tester (MDT) wireline tool. Four such tests, ranging from six to twelve hours duration, were conducted. This field program demonstrated the ability to safely and efficiently conduct a research-level openhole data acquisition program in shallow, sub-permafrost sediments. The program also demonstrated the soundness of the program's pre-drill gas hydrate characterization methods and increased confidence in gas hydrate resource assessment methodologies for the ANS.
Date: January 1, 2008
Creator: Boswell, R.M.; Hunter, R. (ASRC Energy Services, Anchorage, AK); Collett, T. (USGS, Denver, CO); Digert, S. (BP Exploration (Alaska) Inc., Anchorage, AK); Hancock, S. (RPS Energy Canada, Calgary, Alberta, Canada); Weeks, M. (BP Exploration (Alaska) Inc., Anchorage, AK) et al.
Partner: UNT Libraries Government Documents Department

Comparison of kinetic and equilibrium reaction models insimulating gas hydrate behavior in porous media

Description: In this study we compare the use of kinetic and equilibriumreaction models in the simulation of gas (methane) hydrate behavior inporous media. Our objective is to evaluate through numerical simulationthe importance of employing kinetic versus equilibrium reaction modelsfor predicting the response of hydrate-bearing systems to externalstimuli, such as changes in pressure and temperature. Specifically, we(1) analyze and compare the responses simulated using both reactionmodels for natural gas production from hydrates in various settings andfor the case of depressurization in a hydrate-bearing core duringextraction; and (2) examine the sensitivity to factors such as initialhydrate saturation, hydrate reaction surface area, and numericaldiscretization. We find that for large-scale systems undergoing thermalstimulation and depressurization, the calculated responses for bothreaction models are remarkably similar, though some differences areobserved at early times. However, for modeling short-term processes, suchas the rapid recovery of a hydrate-bearing core, kinetic limitations canbe important, and neglecting them may lead to significantunder-prediction of recoverable hydrate. The use of the equilibriumreaction model often appears to be justified and preferred for simulatingthe behavior of gas hydrates, given that the computational demands forthe kinetic reaction model far exceed those for the equilibrium reactionmodel.
Date: November 29, 2006
Creator: Kowalsky, Michael B. & Moridis, George J.
Partner: UNT Libraries Government Documents Department

Comparison of kinetic and equilibrium reaction models insimulating the behavior of porous media

Description: In this study we compare the use of kinetic and equilibriumreaction models in the simulation of gas (methane) hydrate behavior inporous media. Our objective is to evaluate through numerical simulationthe importance of employing kinetic versus equilibrium reaction modelsfor predicting the response of hydrate-bearing systems to externalstimuli, such as changes in pressure and temperature. Specifically, we(1) analyze and compare the responses simulated using both reactionmodels for natural gas production from hydrates in various settings andfor the case of depressurization in a hydrate-bearing core duringextraction; and (2) examine the sensitivity to factors such as initialhydrate saturation, hydrate reaction surface area, and numericaldiscretization. We find that for large-scale systems undergoing thermalstimulation and depressurization, the calculated responses for bothreaction models are remarkably similar, though some differences areobserved at early times. However, for modeling short-term processes, suchas the rapid recovery of a hydrate-bearing core, kinetic limitations canbe important, and neglecting them may lead to significantunder-prediction of recoverable hydrate. Assuming validity of the mostaccurate kinetic reaction model that is currently available, the use ofthe equilibrium reaction model often appears to be justified andpreferred for simulating the behavior of gas hydrates, given that thecomputational demands for the kinetic reaction model far exceed those forthe equilibrium reaction model.
Date: November 29, 2006
Creator: Kowalsky, Michael B. & Moridis, George J.
Partner: UNT Libraries Government Documents Department

Thermal decomposition of UO{sub 3}-2H{sub 2}0

Description: The first part of the report summarizes the literature data regarding the uranium trioxide water system. In the second part, the experimental aspects are presented. An experimental program has been set up to determine the steps and species involved in decomposition of uranium oxide di-hydrate. Particular attention has been paid to determine both loss of free water (moisture in the fuel) and loss of chemically bound water (decomposition of hydrates). The influence of water pressure on decomposition has been taken into account.
Date: February 26, 1998
Creator: Flament, T.A.
Partner: UNT Libraries Government Documents Department

In-Situ Sampling and Characterization of Naturally Occurring Marine Methane Hydrate Using the D/V JOIDES Resolution

Description: The primary accomplishments of the JOI Cooperative Agreement with DOE/NETL in this quarter were that: (1) post-cruise evaluation of the data, tools and measurement systems that were used during ODP Leg 204 continued in the preparation of deliverables under this agreement. Work continued on analyzing data collected during ODP Leg 204 and preparing reports on the outcomes of Phase 1 projects as well as developing plans for Phase 2.
Date: June 30, 2004
Creator: Rack, Frank & Party, ODP Leg 204 Shipboard Scientific
Partner: UNT Libraries Government Documents Department

In-Situ Sampling and Characterization of Naturally Occurring Marine Methane Hydrate Using the D/V JOIDES Resolution

Description: The primary accomplishments of the JOI Cooperative Agreement with DOE/NETL in this quarter were that: (1) postcruise evaluation of the data, tools and measurement systems that were used during ODP Leg 204 continued in the preparation of deliverables under this agreement. Work continued on analyzing data collected during ODP Leg 204 and preparing reports on the outcomes of Phase 1 projects as well as developing plans for Phase 2.
Date: September 30, 2004
Creator: Rack, Frank R. & Party, ODP Leg 204 Shipboard Scientific
Partner: UNT Libraries Government Documents Department

Simteche Hydrate CO2 Capture Process

Description: As a result of an August 4, 2005 project review meeting held at Los Alamos National Laboratory (LANL) to assess the project's technical progress, Nexant/Simteche/LANL project team was asked to meet four targets related to the existing project efforts. The four targets were to be accomplished by the September 30, 2006. These four targets were: (1) The CO{sub 2} hydrate process needs to show, through engineering and sensitivity analysis, that it can achieve 90% CO{sub 2} capture from the treated syngas stream, operating at 1000 psia. The cost should indicate the potential of achieving the Sequestration Program's cost target of less than 10% increase in the cost of electricity (COE) of the non-CO{sub 2} removal IGCC plant or demonstrate a significant cost reduction from the Selexol process cost developed in the Phase II engineering analysis. (2) The ability to meet the 20% cost share requirement for research level efforts. (3) LANL identifies through equilibrium and bench scale testing a once-through 90% CO{sub 2} capture promoter that supports the potential to achieve the Sequestration Program's cost target. Nexant is to perform an engineering analysis case to verify any economic benefits, as needed; no ETM validation is required, however, for this promoter for FY06. (4) The CO{sub 2} hydrate once-through process is to be validated at 1000 psia with the ETM at a CO{sub 2} capture rate of 60% without H{sub 2}S. The performance of 68% rate of capture is based on a batch, equilibrium data with H{sub 2}S. Validation of the test results is required through multiple runs and engineering calculations. Operational issues will be solved that will specifically effect the validation of the technology. Nexant was given the primary responsibility for Target No.1, while Simteche was mainly responsible for Target No.2; with LANL having the responsibility of Targets No.3 and ...
Date: September 30, 2006
Creator: Laboratory, Nexant and Los Alamos National
Partner: UNT Libraries Government Documents Department

METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

Description: Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope drilled and cored a well The HOT ICE No.1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report.
Date: July 1, 2004
Creator: Williams, Thomas E.; Millheim, Keith & King, Buddy
Partner: UNT Libraries Government Documents Department

Hydrate Control for Gas Storage Operations

Description: The overall objective of this project was to identify low cost hydrate control options to help mitigate and solve hydrate problems that occur in moderate and high pressure natural gas storage field operations. The study includes data on a number of flow configurations, fluids and control options that are common in natural gas storage field flow lines. The final phase of this work brings together data and experience from the hydrate flow test facility and multiple field and operator sources. It includes a compilation of basic information on operating conditions as well as candidate field separation options. Lastly the work is integrated with the work with the initial work to provide a comprehensive view of gas storage field hydrate control for field operations and storage field personnel.
Date: October 31, 2008
Creator: Savidge, Jeffrey
Partner: UNT Libraries Government Documents Department

A Domain Decomposition Approach for Large-Scale Simulations of Flow Processes in Hydrate-Bearing Geologic Media

Description: Simulation of the system behavior of hydrate-bearing geologic media involves solving fully coupled mass- and heat-balance equations. In this study, we develop a domain decomposition approach for large-scale gas hydrate simulations with coarse-granularity parallel computation. This approach partitions a simulation domain into small subdomains. The full model domain, consisting of discrete subdomains, is still simulated simultaneously by using multiple processes/processors. Each processor is dedicated to following tasks of the partitioned subdomain: updating thermophysical properties, assembling mass- and energy-balance equations, solving linear equation systems, and performing various other local computations. The linearized equation systems are solved in parallel with a parallel linear solver, using an efficient interprocess communication scheme. This new domain decomposition approach has been implemented into the TOUGH+HYDRATE code and has demonstrated excellent speedup and good scalability. In this paper, we will demonstrate applications for the new approach in simulating field-scale models for gas production from gas-hydrate deposits.
Date: July 1, 2008
Creator: Zhang, Keni; Moridis, G.J.; Wu, Y.-S. & Pruess, K.
Partner: UNT Libraries Government Documents Department