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91.
Prediction of surface horizontal displacements, and gravity and tilt changes caused by filling the Three Gorges Reservoir 总被引:11,自引:0,他引:11
Horizontal displacements, and gravity and tilt changes induced by filling the Three Gorges Reservoir are modeled using elastic
loading Green functions. When the water surface reaches its highest level, the effects become maximum on the reservoir banks.
The longitudinal and latitudinal components of the horizontal displacements reach −8.2 and 7.7 mm respectively, gravity is
increased by up to 3.4 mGal, and the prime vertical and meridian components of the tilt changes are −7.8 and −17.5 arcseconds
respectively. Accordingly, the filling of the reservoir will influence values observed from global positioning system (GPS),
gravimetry and tilt measurements in the area. The results given can be used to provide important corrections for extracting
earthquake-related signals from observed data.
Received: 19 January 2001 / Accepted: 3 September 2001 相似文献
92.
从已发现的油气田看中国海相油气勘探 总被引:5,自引:1,他引:5
中国海相油气勘探的主要目标是古生界碳酸盐岩,在漫长的演化历程中它的主要成藏类型是准原生型。对形成保存至今的工业油气藏来说,碳酸盐岩中有效烃源岩的总有机碳含量下限应≥0.5%,滨海相或海陆交互相煤系可对生烃作出重大贡献。碳酸盐岩中的储集体受裂缝—岩溶发育程度的控制而分为三种基本类型:(1)以孤立的缝洞储集体为主者称纳溪型,各储集体内的流体性质、压力均可有不同;(2)各储集体间相互连通从而有统一的压力和气、油、水界面,若其似块状者称任丘型,若其似层状者则称威远型;(3)居于这两个端元间的过渡类型为塔河型,其各部分之间的流体性质和压力可有一定差别,无统一油水界面。应注意对似层状储集体的勘探研究,保存条件的好坏对海相油气田有决定性的意义。在分析复杂的多期成藏史中,要注意古隆起和晚期成藏的辩证关系。我国的海相油气勘探有难度,要重新评价有效和高效烃源岩,从较浅部和次生油气蒇入手逼近油气源,寻找主力油气藏,要重视岩性圈闭和各构造(形变)层间的不吻合性。中国的海相油气勘探方向可分为优先勘探、立争突破、劣中选优三个层次。 相似文献
93.
中国古生界海相地层油气勘探 总被引:1,自引:0,他引:1
影响中国古生界海相油气勘探并且需要加强研究的主要问题是:保存条件的认识与有利区预测;有效烃源岩与资源潜力;储层的复杂性及其对非构造圈闭的影响。保存条件分为三个层次:含油气盆地的保存、含油气系统的保存、油气藏的保存。塔里木、四川、鄂尔多斯三大克拉通盆地是中国古生界保存较好的盆地,是海相油气勘探的战略目标区,另外还有准噶尔、楚雄等盆地。盆地斜坡相泥岩及泥状灰岩是海相油气勘探的主要烃源;海陆过渡相烃源岩发育区是重要战略方向;陆表海碳酸盐岩烃源岩区是中小油气田勘探领域。从储层条件来说,下古生界应以非砂岩岩溶储层为主要勘探对象,溶蚀不整合面广泛发育,已发现的下古生界大中型油气田仅见于碳酸盐岩溶储层;上古生界以孔隙性碎屑岩及碳酸盐岩储层为主要勘探对象,晚古生代的构造一古地理演化为这两类储层的广泛发育提供了条件。 相似文献
94.
溱潼凹陷台南油田储层非均质性严重,极大地影响了油田的开发效率。运用变差函数方法,研究井间储层纵,横向变化的特点,用克立金法和条件模拟法建立台南油田储层地质模型。该模型在油田开发调整井部署,注采井设计等方面取得了较好的应用效果。 相似文献
95.
96.
97.
Vertical distribution of the dominant planktonic crustaceans in a mesotrophic reservoir, Xujiahe reservoir (central China) 总被引:1,自引:0,他引:1
The day and night vertical distributions of the dominant planktonic crustaceans in Xujiahe Reservoir were investigated on July 7, 1998. Sampling was carried out at Station D in the upstream region, Doupuohe, and Stations LI and LII in the downstream region, Lujiaodao. At Station D and Station LI, Leptodora kindti showed diel vertical migrations. In Daphnia galeata and Diaphanosoma dubia a limited reverse diel vertical migration was found at Station D, and large individuals tended to stay in lower layers during the day. Neutrodiaptomus incongruens seemed to avoid the water column of 0–6 m by day, but a detectable proportion of the population moved upwards at night. Mesocyclops thermocyclopoides showed a clearly defined diel vertical migration behavior at all three stations. The vertical distribution of Thermocyclops crassus was similar at different stations: in daylight hours it was found almost exclusively in the water column below 6 m and during the night a significant proportion of the population shifted upwards. 相似文献
98.
Reservoirs have to be released when repairing of the dams is necessary. In 1995, two reservoirs in Baden-Württemberg (Germany) of similar age and volume (Lake Herrenbach near Göppingen, 1.0 Mio. m3 and Lake Breitenau near Heilbronn, 2.3 Mio. m3) were emptied. This allowed the singular possibility to investigate the effects of drainage and refilling on the limnochemistry and the phytoplankton biocoenosis of such artificial lakes.Before the drainage of the reservoirs, both lakes showed phosphorus release from the sediment during summer stagnation. Phosphorus values of Lake Herrenbach were regularly higher than those of Lake Breitenau (Lake Herrenbach 88 μg/l, Lake Breitenau 33 μg/l). During release, both lakes indicated higher phosphorus and chlorophyll concentrations as well as rising biomasses. Remarkable differences were observed during refilling of the reservoirs: while Lake Herrenbach showed higher transparency and lower phosphorus concentrations, Lake Breitenau progressed towards eutrophication (total phosphorus during summer 1996: Lake Herrenbach 30 μg/l, Lake Breitenau 55 μg/l). One reason for the reaction of Lake Breitenau was the reduced ground drainage during the refilling, which caused an accumulation of nutrients in the hypolimnion. Another reason was the mineralisation of vegetation which covered great parts of the dry lake sediment. The limnological change of Lake Herrenbach was not as clear but could be caused by the restauration of the pre-reservoir which was drainaged and dredged before the emptying of the main reservoir started as well as many other facts which differed Lake Herrenbach from Lake Breitenau. 相似文献
99.
100.
Hu Yuliang Liu Zuyuan Yang Oingyuan Chen Xiancheng Hu Ping Ma Wentao Lei Jun 《Pure and Applied Geophysics》1996,147(2):409-418
To date 19 cases of reservoir-induced seismicity have been acknowledged in China and 15 of them are associated with karst. The Wujiangdu case is a typical one induced in the karst area. The dam with a height of 165 m is the highest built in a karst area in China. Seismic activity has been successively induced in five reservoir segments seven months after the impoundment in 1979. A temporary seismic network consisting of 8 stations was set up in one of the segments some 40 km upstream from the dam. The results indicate that epicenters were distributed along the immediate banks, composed of karstified carbonate, and focal depths were only several hundred meters. Most of the focal mechanisms were of thrust and normal faulting. It is suggested that karst may be an important factor in inducing seismicity. It can provide an hydraulic connection to change the saturation and pressure and also weak planes for dislocation to induce seismicity. 相似文献