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Defining temperature at depth to identify geothermal resources relies on the evaluation of the Earth heat flow based on equilibrium temperature measurements as well as thermal conductivity and heat generation rate assessment. Such high-quality geothermal data can be sparse over the region of interest. This is the case of the St. Lawrence Lowlands sedimentary basin covering 20,000 km2 to the south of Québec, Canada, and enclosing only three wells up to a depth of 500 m with equilibrium heat flow measurements. However, more than 250 oil and gas exploration wells have been drilled in this area, providing for this study (parce que c'est 93 sinon) 81 locations with bottom-hole temperature up to a depth of 4300 m, however, not at equilibrium. Analyzing these data with respect to the deep geothermal resource potential of this sedimentary basin requires evaluating the thermal conductivity and heat generation rate of its geological units to properly extrapolate temperature downward. This was done by compiling literature and recent thermal conductivity measurements in outcrop and core samples as well as new heat generation rate estimates from spectral gamma ray logs to establish a first thermal assessment of geological units deep down into the basin. The mean thermal conductivity of the thermal units varies from 2.5 to 6.3 W/m·K, with peak values in the basal sandstones, while the heat generation rate varies from 1.6 to 0.3 µW/m3, decreasing from the upper caprocks toward the base of the sequence. After correcting the bottom-hole temperatures for drilling disturbance with the Harrison correction and subsequently for paleoclimate variations, results indicate a mean geothermal gradient of 23.1 °C/km, varying from 14 to 40 °C/km. Evaluating the basin thermal state from oil and gas data is a significant challenge facilitated by an understanding of its thermal properties.  相似文献   

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An outline is given of the career and scientific and teaching activity of the outstanding geomorphologist, professor of Moscow State University S.S. Voskresenskii, who created new scientific directions in the study of topography. He is rightfully given credit for geographical investigations of Siberia and the Far East in the latter half of the 20th century.  相似文献   

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ThepreliminarystudyofthephytoplanktonecologyintheGreatWallBay,AntarcticaYuJianluan(俞建銮);LiRuixiang(李瑞香)andHuangFengpeng(黄凤鹏)(...  相似文献   

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In this paper, we explore migration aspects of the 1995 Quebec Sovereignty Referendum with data from a survey administered to non-francophones in Montreal two weeks prior to the Referendum. While the Quebec sovereignty issue has been around for some time and earlier exodus from the province, particularly among anglophones, is largely regarded as “forced” in some way, this study neither confirms the 1995 Sovereignty Referendum as a paramount factor in explaining outmigration from Quebec nor points to a real reluctance to leave Montreal. The decision to move is influenced by the interplay of a multitude of factors. The political influence is only an added factor to longstanding economic decline and cultural clash. Moreover, if there is any impulsion, the degree varies among different cultural and socioeconomic groups.  相似文献   

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Based on biomass investigations,soil respiration and plant photosynthesis measurement of dominant trees in Hailuogou valley of Mt.Gongga,Southwest China,the carbon(C) storage,absorption and release for several typical woodlands in sub-alpine zones have been discussed.For Abies fahri forest of 3,000 m above sea level,the Cstorage amount is 177.4t/ha for above-ground biomass and 143.2 t/ha for soil below-ground biomass. The annual gross C fixed by vegetation photosynthesis is 20-24 t/ha. The C release by canopy respiration is 3.0-5.5 t/ha for arbors and 10-19 t/ha for surface soil and roots.The annual net C fixed of forest ecosystem is about 6.0-7.1 t/ha.At lower elevations,the amount of C released by woodlands is higher than that of woods at higher elevations.The C fixed capacity of renewed forest with middle-aged trees is higher than that of mature forest.Before becoming over-matured forest,woodland is an important sink of C whereas bareland in woods is the source of atmospheric C.  相似文献   

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The 8th Intemational Riversymposium was held in Brisbane, Australia on 6-9 September 2005. The Intemational Riversymposium is an integral part of Brisbane's annual broadbased cultural event. The Queensland Government is a foundation partner of the Intemational River Foundation, formed to secure the future of the Intemational and National Thiess Riverprize. The theme of symposium in this year is “Water and Food Security- Rivers in a Global Context” ( www.riversymposium.com ). The Riversymposium provides a global forum which aims to make a difference to the declining state of rivers and waterways globally. Its strength lies in the breadth of its challenging program content of important keynote presentations and case studies of rivers in crisis, attracting a diverse range of national and intemational delegates. Some 450 scientists from 38 countries attended this conference, and about 100 papers were presented on the symposium in 2005.  相似文献   

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