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101.
陈国阶 《中国地理科学(英文版)》1998,8(2):97-105
ASSESSMENTOFECONOMICDEVELOPMENTFORTHREEGORGESRESERVIORAREA①ChenGuojie(陈国阶)ChengduInstituteofMountainHazards&Environment,theCh... 相似文献
102.
三峡库区农业生态经济系统的预警分析 总被引:1,自引:1,他引:0
从系统与环境相统一的角度,研究了农业生态经济系统的模型、特征、预警分析的意义和内容;以三峡库区为例,从系统序化的观点,确定了这个系统的社会、经济、环境功能和状态的主要指标的警戒线;并与这些指标的现状、过去与未来趋势值进行对比;分别对现状预警、趋势预警和突变预警进行了评价;最后作了简易的对策探讨. 相似文献
103.
1975 ̄1991年间,广东河源市新丰江水库区发生了5次ML4.7 ̄5.1级地震。距震中10km以内的河源黄子洞地电台记录到了震前不同程度的地电阻率异常变化。采用距平法消除年变干扰后异常延续时间一般为3个月左右,电阻率异常下降幅度在1%左右。利用《指南》中的震兆异常信度分析法确认其异常信度后,利用模糊信息处理法对异常判定地震三要素进行了计算,结果与实际基本符合。 相似文献
104.
Su Chin CHEN 《国际泥沙研究》1998,(3)
RESERVOIRSEDIMENTATIONANDLANDUSEINTAIWANWUSHEHWATERSHEDSuChinCHEN1ABSTRACTWushehReservoirisagorgetypehydropowerReservoironW... 相似文献
105.
Hubert CHANSON 《国际泥沙研究》1998,(3)
EXTREMERESERVOIRSEDIMENTATIONINAUSTRALIA:AREVIEWHubertCHANSON1ABSTRACTInthepaper,theauthorreviewstheproblemofreservoirsiltati... 相似文献
106.
PREDICTINGRESERVOIRSEDIMENTATIONWITH2DMODELFLOODSIMW.BECHTELER1andM.NUJIC2ABSTRACTPredictionofsedimentationisveryimportantbef... 相似文献
107.
108.
D. S. Suresh Babu V. Nandakumar B. John B. K. Jayaprasad S. V. Pramod 《Environmental Geology》2000,39(3-4):390-397
Impact of catchment erosion and the resultant reservoir siltation from a tropical environment is reported here to discuss
the effect of a reservoir in the natural degradation of an evergreen-forested segment. While an area of 8.01 km2 has been affected by direct inundation at the full reservoir level, another 2.6 km2 area once under thick forest cover, had also lost its identity over the last 38 years by indirect degradation. This zone
mainly falls in the confluence of tributaries, namely Neyyar and Mullayar, with the reservoir. The capacity of the reservoir
was found to be reduced by 28.8 Mm3 during this period and the annual average loss is calculated as 0.75 Mm3 (0.71%), indicating the intensity of erosion from the catchment zone. In case the proposed upper dam in the reservoir comes
into existence, an additional area of 2.4 km2 from the virgin forest would be submerged and more area would face degradation around the inundated zone.
Received: 29 July 1998 · Accepted: 16 November 1998 相似文献
109.
To unravel the mystery of the relationship between evaporates, Ca–Cl brines and accumulations of oil and N2 in the basins of ancient cratons, their N2, CH4 and He concentration ratios, as well as the isotopic composition (δ15N, δ13C and 3He/4He) were compared within the Volga-Ural basin. The study allowed subsalt fluids from Volga-Ural Basin to divide into two genetic groups. The first one is found within the basin's platform area. It includes Ca–Cl brines, high-viscosity heavy oil, bitumen and N2, which has concentrations higher than that of CH4 and positive values of δ15N. The second one is tied to the edge of the platform, the Ural Foredeep and Peri-Caspian Depression. In this group, only the oil and gas reservoirs, which have more CH4 than N2, and possibly negative values of δ15N, were discovered. Interaction of gas components in compared fluids indicates great role of degassing in the formation of their composition. It is suggested that the fluids of the first group (N2 > CH4) is what remains, and the second group (N2 < CH4) is what is disappears from the rocks during their metamorphism and degassing. 相似文献
110.
The Basque–Cantabrian Basin (NE Spain) has been considered one of the most interesting areas for hydrocarbon exploration in the Iberian Peninsula since the 60th to 70th of last century. This basin is characterized by the presence of numerous outcrops of tar sands closely associated with fractures and Triassic diapirs. The aims of this work is to establish the diagenetic evolution of the Upper Cretaceous reservoir rocks with special emphasis in the emplacement of oil and their impact on reservoir quality. The studied rocks are constituted of carbonates and sandstones that contain massive quantities of bitumen filling vugs and fractures.Petrographic results indicate that the carbonate rocks from Maestu outcrops are bioclastic grainstones and wackestones, whereas the tar sandstones from Atauri and Loza outcrops are dominated by quartzarenites and subordinated subarkoses. The paragenetic sequence of the main diagenetic phases and processes include, pyrite, bladed and drusy calcite cement, calcite overgrowths, silicification of bioclasts and microcrystalline rhombic dolomite cement, and first stage of oil emplacement, blocky calcite cement, coarse crystalline calcite cement, calcitized dolomite, calcite veins, saddle dolomite and stylolites filled by the second phase of oil entrance. Together with the above mentioned diagenetic alterations, the arenites are affected by early kaolinitization of feldspars and the scarce formation of clay rim and epimatrix of illite. All sandstones and dolomitized carbonate rocks show high intercrystalline and intergranular porosity which is full by biodegraded hydrocarbons (solid bitumen). The biodegradation affects alkanes, isoprenoids and partially hopanes and steranes saturated hydrocarbons. Aromatics hydrocarbons, like naphthalenes, phenanthrenes, dibenzothiophenes and triaromatics are also affected by biodegradation. Results indicate that the first HC emplacement corresponds to early stage of calcite and dolomite cementation, and the second and more important emplacement is related to fracturation processes resulting in the formation of excellent reservoirs. 相似文献