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991.
GuoYi Hu Jin Li HuiYing Cui QiGui Ran Li Zhang XiaoBo Wang YiFeng Wang 《中国科学D辑(英文版)》2009,52(1):96-105
Focusing on the two natural gas exploration geological problems with abundant source of oil cracking gas in the late stage and the sealing condition of the oil cracking gas reservoir, the kinetics of oil cracking gas and the evaluation parameters of gas cap rock are adopted to the study on the natural gas accumulation conditions in the Tadong area. Both the study on the kinetics of oil cracking gas and the statistical results of reservoir bitumen reveal that the geological formation of oil cracking gas in the Tadong area is located in the top of Cambrian. Two kinds of oil cracking gas geological models at least, namely well Mandong-1’s early rapid generation model (Middle Ordovician-end Silurian) and peak cracking model (with the natural gas conversion rate >90%), namely well Yingnan-2’s two-stage generation model of oil cracking gas, have been set up. The oil cracking gas of Yingnan-2 in the late stage is very significant in the evaluation of natural gas exploration in the Tadong area. The evaluation results of the cap rock show that the microscopic parameters of cap rock from the lower assemblage of Cambrian-Ordovician are better than those from the upper assemblage. The former has strong capillary sealing ability and higher cap rock breakthrough pressure than the upper assemblage, with strong sealing ability, so that natural gas dissipates mainly by diffusion. According to the above investigations, the lower assemblage Cambrian-Ordovician natural gas of Kongquehe slope, Tadong low uplift and Yingjisu depression in the Tadong area prospects well. 相似文献
992.
Most-probable-number (MPN) dilution series were used to enumerate and isolate bacteria from bulk water, suspended aggregates, the oxic layer, and the oxic–anoxic transition zone of the sediment of a tidal flat ecosystem in the southern North Sea. The heterotrophic aerobic bacteria were able to grow on agar-agar, alginate, cellulose, chitin, dried and ground Fucus vesiculosus, Marine Broth 2216, palmitate, and starch. MPN counts of bulk water and aggregate samples ranged between 0.18?×?101 and 1.1?×?106 cells per milliliter and those of the sediment surface and the transition zone between 0.8?×?101 and 5.1?×?107 cells per gram dry weight. Marine Broth and F. vesiculosus yielded the highest values of all substrates tested and corresponded to 2.3–32% of 4,6-diamidinophenyl indole cell counts. Strains of seven phylogenetic classes were obtained: Actinobacteria, Bacilli, α- and γ-Proteobacteria, Sphingobacteria, Flavobacteria, and Planctomycetacia. Only with agar-agar as substrate could organisms of all seven classes be isolated. 相似文献
993.
Stefan Jansen Eva Walpersdorf Ursula Werner Markus Billerbeck Michael E Böttcher Dirk de Beer 《Ocean Dynamics》2009,59(2):317-332
In this article, we describe the dynamics of pH, O2 and H2S in the top 5–10 cm of an intertidal flat consisting of permeable sand. These dynamics were measured at the low water line
and higher up the flat and during several seasons. Together with pore water nutrient data, the dynamics confirm that two types
of transport act as driving forces for the cycling of elements (Billerbeck et al. 2006b): Fast surface dynamics of pore water chemistry occur only during inundation. Thus, they must be driven by hydraulics (tidal
and wave action) and are highly dependent on weather conditions. This was demonstrated clearly by quick variation in oxygen
penetration depth: Seeps are active at low tide only, indicating that the pore water flow in them is driven by a pressure
head developing at low tide. The seeps are fed by slow transport of pore water over long distances in the deeper sediment.
In the seeps, high concentrations of degradation products such as nutrients and sulphide were found, showing them to be the
outlets of deep-seated degradation processes. The degradation products appear toxic for bioturbating/bioirrigating organisms,
as a consequence of which, these were absent in the wider seep areas. These two mechanisms driving advection determine oxygen
dynamics in these flats, whereas bioirrigation plays a minor role. The deep circulation causes a characteristic distribution
of strongly reduced pore water near the low water line and rather more oxidised sediments in the centre of the flats. The
two combined transport phenomena determine the fluxes of solutes and gases from the sediment to the surface water and in this
way create specific niches for various types of microorganisms. 相似文献
994.
Information included in this summary is based on more detailed reports published in the Bulletin of the Global Volcanism Network,
vol. 33, no. 7, July 2008 (on the Internet at ). Edited by scientists at the Smithsonian, this bulletin includes reports provided by a worldwide network of correspondents.
The reports contain the names and contact information for all sources. Please note that these reports are preliminary and
subject to change as events are studied in more detail. The Global Volcanism Program welcomes further reports of current volcanism,
seismic unrest, monitoring data, and field observations. 相似文献
995.
Claude Robin Jean-Philippe Eissen Pablo Samaniego Hervé Martin Minard Hall Joseph Cotten 《Bulletin of Volcanology》2009,71(3):233-258
The Mojanda–Fuya Fuya Volcanic Complex consists of two nearby volcanoes, Mojanda and Fuya Fuya. The older one, Mojanda volcano
(0.6 to 0.2 Ma), was first constructed by andesites and high-silica andesites forming a large stratovolcano (Lower Mojanda).
This edifice was capped by a basaltic andesite and andesitic cone (Upper Mojanda), which collapsed later to form a 3-km-wide
summit caldera, after large phreatomagmatic eruptions. The Lower Fuya Fuya edifice was constructed by the extrusion of viscous
Si-rich andesitic lavas and dacitic domes, and the emission of a thick sequence of pyroclastic-flow and fallout deposits which
include two voluminous rhyolitic layers. An intermediate construction phase at Fuya Fuya is represented by a mainly effusive
cone, andesitic in composition (San Bartolo edifice), the construction of which was interrupted by a major sector collapse
in the Late Pleistocene. Finally, a complex of thick siliceous lavas and domes was emplaced within the avalanche amphitheatre,
forming the Upper Fuya Fuya volcanic centre. This paper shows that the general evolution from an effusive to an explosive
eruptive style is related to a progressive adakitic contribution to the magma source. Although all the rocks of the complex
are included in the medium-K field of continental arcs, the Fuya Fuya suite (61–75 wt.% SiO2) shows depletion in Y and HREE and high Sr/Y and La/Yb values, compared to the less silicic Mojanda suite (55–66.5 wt.% SiO2). The Mojanda calc-alkaline suite was generated by partial melting of an adakite-metasomatised mantle source that left a
residue with 2% garnet, followed by fractional crystallization of dominant plagioclase + pyroxene + olivine at shallow, intra-crustal
depths. For Fuya Fuya, geochemical and mineralogical data suggest either (1) partial melting of a similar metasomatised mantle
with more garnet in the residue (4%), followed by fractional crystallization involving plagioclase, amphibole and pyroxene,
or (2) mixing of mafic mantle-derived magma from the Mojanda suite and slab melts, followed by the same fractional crystallization
process. 相似文献
996.
This paper presents an indirect boundary integration equation method for diffraction of plane P waves by a two-dimensional canyon of arbitrary shape in poroelastic half-space. The Green’s functions of compressional and shear wave sources in poroelastic half-space are derived based on Biot’s theory. The scattered waves are constructed using the fictitious wave sources close to the boundary of the canyon, and magnitude of the fictitious wave sources are determined by the boundary conditions. The precision of ... 相似文献
997.
Inthepresentpaper,themultifluidsmodelfortwophaseflowsandthek-ε-Apturbulencemodelareusedtocalculatethethreedimensionalturbulent?.. 相似文献
998.
The constitutive theory on the viscoelastoplasticity and damage of frozen soil is based on the continuous mechanics and thermodynamics. The basic principles of the theory, dissipation potential function and damage model are presented. The constitutive theory explains the mechanical properties of frozen soils under complicated stresses, especially under high confining pressures which make frozen soil harden and soften. The agreement between the calculated results by the constitutive theory and the experimental results of triaxial creep of frozen soil is seen to be very good. 相似文献
999.
The control of synchronous structures on formation of superlarge stratabound ore deposits is immense. Based on studies of ore deposits in South Qiniing, northern Guangdong, Langshan and other areas, three new ideas in comparison with examples of ore control of synchronous structures both in China and abroad are proposed: (i) multiorder ore control of synchronous structures, which means that synchronous structures of different orders display different controls on ore deposits; (ii) synchronous structures in different stages of basin evolution display different controls on basin fluid system and ore-forming system; (iii) synchronous strurture accompanying hydrothermal mineralization as a preexisting weak surface in earth crust often reactivate in later tcctono-thermal event to be a channelway for magma or thermal fluids which superimposed on and reformed preexisting ore beds to form large or superlarge composite ore deposits. 相似文献
1000.
Depth profiles of fluorescence at several excitation and emission wavelengths were measured along with CTD data during the
cruise So119 of RV Sonne in the Arabian Sea from 12 May to 10 June 1997. In addition to chlorophyll fluorescence from phytoplankton in the near-surface
layer, the profiles in the oxygen minimum region well below the euphotic zone show enhanced red fluorescence. Red fluorescence
intensity is inversely related to the oxygen concentration in intermediate and deep waters. A relationship to characteristic
water masses of the region cannot be found in the data, and this holds also with chemical data such as DOC. Absorbance spectra
of water samples taken in the oxygen minimum zone show an absorption band at 420 nm wavelength with about 50 nm bandwidth,
much weaker than gelbstoff absorbance in the same wavelength range. The absorption band remains stable after sample filtration
with 0.45 μm glass fibre filters. Hence, the size of the absorbing matter is in the range of dissolved molecules or particles
much smaller than 1 μm. Fluorescence spectra of unfiltered samples with 420 nm excitation show a weak emission band at 600
nm and a more pronounced one at 660 nm wavelength. The trailing edge of the 660 nm band falls into the range of chlorophyll
emission, thus giving rise to the observed depth profiles of red fluorescence in the oxygen minimum zone. Red fluorescence
measured on samples remain stable during a few hours after sampling even in the presence of oxygen. It is not detectable after
several weeks of sample storage in the dark and cannot be reproduced even after depletion of dissolved oxygen.
Received: 22 May 2002 / Accepted: 18 February 2003
Responsible Editor: Andreas Oschlies
Acknowledgements. This work was supported by a grant from the Federal Minister of Education and Technology, Bonn, within the frame work of
the JGOFS Arabian Sea program. We are grateful to the captain and the crew of RV Sonne for their support. We are indebted to Mrs. Kirsten Neumann from the Institute of Marine Chemistry and Biogeochemistry of
the University of Hamburg for providing the oxygen data, and to Mr. Nikolai Delling from the same institute for making the
DOC and chlorophyll data available to us. 相似文献