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321.
322.
In the process of steam stimulation exploitation of viscous crude oil, the injected water, at high temperature and under high pressure, reacts intensively with the host rock. This kind of water–rock interaction in Liaohe Shuguang Oil Field was studied on the basis of analysis of water composition changes, laboratory experiments, mineral saturation indices analysis, and mass balance calculation. Compared with the injected water, the changes of the composition of discharged water are mainly the distinct decrease of pH, Na+, SiO2 and Cl−, as well as the increase of K+, Ca2+, Mg2+, SO
4
2−
and HCO
3
−
. Laboratory experiments under field conditions showed: the dissolution sequence of minerals quantitatively is quartz>potassium feldspar>albite, and the main change of clay minerals is the conversion of kaolinite to analcime. Mass balance calculation indicated during the process of steam stimulation, large quantities of analcime are precipitated with the dissolution of large amounts of quartz, kaolinite, potassium feldspar, and CO2. These results correlated very well with the experimental results. The calculated results of Liaohe Shuguang Oil Field showed that during the steam stimulation for viscous crude oil, the amounts of minerals dissolved (precipitated) are huge. To control the clogging of pore spaces of oil reservoirs, increased study of water–rock interaction is needed. 相似文献
323.
The Xiangxi River is the first middling tributary of the Changjiang River near the Three Gorges Dam. The River is subject
to phosphorus pollution mainly from industrial wastewater. As the water quality of the Xiangxi River could directly influence
the water quality of the Three Gorges Reservoir, the research on phosphorus levels and its change in the sediment profile
of the Xiangxi River could provide useful information in the dynamic changes in the system, thereby offering options for mitigative
measures. Water and sediment samples from lower reaches of Xiangxi River were collected and the different forms of phosphorus
in sediments of the Xiangxi River were studied. The concentrations of total phosphorus in sediment ranged from 757.67 to 1438.54 mg/kg.
Inorganic phosphorus concentrations ranged from 684.63 to 1055.58 mg/kg. Phosphorus contamination was serious in some parts
of the Xiangxi River. With an average concentration of 635.17 mg/kg, calcium-bound phosphorus is the main form among different
inorganic phosphorus forms. Labile phosphorus and iron/aluminum-bound phosphorus measured 3.40, 0.05and 35.28 mg/kg, respectively.
The mobilization potential of phosphorus of sediments was studied through adsorption and release experiments. The equilibrium
concentration of phosphorus adsorption and release was around 0.1 mg/L. The initial concentrations of phosphorus in the overlying
water and the sediments have obvious effect on phosphorus mobilization potential. In addition, the release rate of phosphorus
in sediment increased with water depth. 相似文献
324.
A short reply to discussion by Chanson. 相似文献
325.
The objective of this study is to investigate pollen-vegetation relationship in the Qilian Mountains. The eastern Qilian Mountains are located in the transitional zone of the Tibetan Plateau, the Loess Plateau and the arid region of Northwest China, which is one of the key areas of global environmental change. A total of 13 surface pollen samples from main vegetation have been collected. Pollen percentages were calculated in all samples. In order to reveal the relationship between pollen composition and the vegetation types from which the soil samples have been collected, Detrended Correspondence Analysis (DCA) ordination method was employed on the pollen data. The results show that dominating vegetation types can be recognized by their pollen spectra: Picea crassifolia forest, alpine shrub and alpine meadow as well. Altitude and temperature determine the distribution of the surface pollen and the vegetation. The good agreement between modern vegetation and surface samples across this area provides a measure of the reliability of using pollen data to reconstruct paleoenvironment and paleovegetation patterns in this or other similar regions. However the loss of Betula pollen in forest needs further investigation. Pollen oxidation is the most important factor contributing to the damage of modern pollen in the study area. Pollen concentrations decrease with the increase of pH values of soils, and decrease sharply when the pH exceeds 7.6. 相似文献
326.
327.
Paul Augustinus Michael Reid Sofia Andersson Yanbin Deng Mark Horrocks 《Journal of Paleolimnology》2006,35(4):789-805
Frozen sediment cores from Lake Pupuke in Auckland City, New Zealand, contain a high resolution decadal to annual scale record
of changing lake paleoenvironments and geochemistry that reflects changing landuse and hydrology in the catchment over the
past c. 190 years. A reliable chronology is available from AMS 14C and 210Pb dating of the sediments, with the timing of the older part of the record supported by the first appearance of pollen of
introduced Pinus and Plantago lanceolata associated with European settlement of Auckland in the early 1840s. Diatom stratigraphy, sediment elemental and carbon isotope
geochemistry reflect changes in sediment sources and lake conditions commensurate with European development of the Lake Pupuke
catchment, in particular enhanced algal productivity controlled by the influx of nutrients after c. 1920 AD. Attempts to prevent
nuisance algal blooms in 1933, 1934 and 1939 using CuSO4 addition produced Cu spikes in the sediment that allowed confirmation of the accuracy of the 210Pb chronology. Hence, the elemental and isotopic composition of the Lake Pupuke sediments reflect the timing of significant
anthropogenic activities, rather than climatic variations, that have occurred within the watershed over the past c. 190 years.
The comparison of records of land use change in the catchment with the multi-proxy record of changes in the sediments usually
allowed unambiguous identification of the signatures of change and their causes. 相似文献
328.
库车坳陷侏罗系煤成气动力学模拟研究 总被引:1,自引:0,他引:1
应用黄金管—高压釜封闭体系热模拟实验与GC、GC-IRMS分析技术,结合KINETICS专用软件,对库车坳陷侏罗系煤成气进行了动力学模拟研究。库车坳陷侏罗系煤具有高的产气性,在高演化阶段主要产甲烷气;侏罗系煤热解气甲烷碳同位素为-36‰~-25‰,乙烷碳同位素为-28‰~-16‰;甲烷、C2-C5气态烃的生成活化能分别为(47~64k)calm/ol、(55~72k)calm/ol,频率因子各为5.265×1013s-1、5.388×1018s-1。在此基础上,进一步探讨了克拉2气田天然气的成因。研究认为,克拉2气田天然气属阶段捕获的煤成气,主要聚集了5~1Ma时期的天然气,其成熟度Ro分布范围为1.3%~2.5%。 相似文献
329.
330.
针对空间数据存储的特点,结合网格和虚拟SAN技术的优势,提出了基于虚拟SAN的网格GIS数据存储解决方案.旨在解决网格GIS环境下的数据存储问题。 相似文献