As a part of a research program aiming to mobilize marine gas hydrate deposits as an energy resource, the worlds' first gas production attempt was performed in early 2013 in the Daini Atsumi Knoll, ...Eastern Nankai Trough, off Honshu Island, Japan. The test concluded with 119 000 m
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(under ambient conditions) of methane gas production during six consecutive days of depressurization operation through a borehole drilled at 1000 m water depth. As thermal and mass transportation in a heterogeneous geological formation are the governing factors of efficiency and effectiveness of the resource, the test was associated with intensive underground temperature monitoring. Temperature sensors installed in one production and two observation boreholes could detect temperature variations during gas production due to the endothermic gas hydrate dissociation process and mass/heat transport around the boreholes. The measurements in the observation holes started one year before the test and continued until plug-and-abandonment, and thus enabled monitoring of both the initial temperature and temperature change arizing from recovery processes. The depth profiles of measured temperatures in all holes can be related to the geological features of the corresponding formation, and those thermal responses revealed the intervals where gas hydrate dissociation predominantly occurred. By analyzing the energy conservation in the production borehole, the gas and water production profiles could be estimated and major gas and water production zones were identified. Preliminary numerical analysis results show the range of formation permeability and that the observed temperature drop is equivalent to the heat consumption by hydrate dissociation for the volume of produced methane gas. Moreover, the thermal responses could provide some clues about the location and mechanism of the sand production event. This sand production event ultimately terminated the production operations on the seventh day of flow.
As a part of a research program aiming to mobilize marine gas hydrate deposits as an energy resource, the worlds' first gas production attempt was performed in early 2013 in the Daini Atsumi Knoll, Eastern Nankai Trough, off Honshu Island, Japan.
The results of an experimental investigation of the transport and the accumulation of the disperse phase of suspensions during its filtration through rock samples are presented. A consistent model of ...the inner and outer filter coke formation is considered. A method of determining the particle pick-up parameters and the permeability reduction coefficient by means of the joint modeling of the filtration experiment data and the profile of the volume concentration of the picked-up suspension particles is proposed. The methods of characterizing the colmatation zone by means of the X-ray computer microtomography and the coloring of clay particles followed by an analysis of the cleavage of the impure sample are presented. The colmatation model is generalized to cover the case in which the porous medium includes two pore continua with different properties.
The results of helium thermal-hydraulic transients of the UNK superconducting magnet system are presented. The model is based on the set of 1-D mass, energy, and momentum conservation equations for ...helium flow in the cooling channels and the heat conduction equation for the wall, subject to appropriate boundary and initial conditions. The mass and energy transfer between helium in the winding gaps and helium flowing in the cooling channels is taken into account. Pressure, temperature, and helium mass flow developments during a quench in the quench protection unit magnets and in the header were calculated. The influence of heat and mass transfer between helium trapped within winding gaps and the helium stream on pressure behavior in the magnet is analyzed. It has been found that the amount of liquid helium contained in the winding affects the maximum quench pressure.< >
The secondary electron rf monitors for short ion bunch phase distribution measurement are presented. Construction particularities of the monitors, influence of space charge of both the primary and ...the secondary electron beams on the phase resolution, thermal regime of the target during beam-target interaction are considered.< >
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