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921.
塔里木盆地塔河油田奥陶系大型油气藏形成条件 总被引:31,自引:4,他引:31
塔河油田位于塔里木盆地北部沙雅隆起阿克库勒凸起的西南部,它是在长期发育的阿克加勒鼻状古隆起基础上形成的下奥陶统盐碉岩溶-缝洞型大型油气田。受区域构造-沉积背景控制,塔河地区下奥陶统属于碳酸盐岩开阔台地环境,一直处于继续性隆起状况,是油气运聚的长期指向区,并经历了多欠的构造运动。岩溶作用和成岩作用的叠加改造,形成了具强烈非均质性的岩溶-缝洞型储层,油气主要赋存于距风化壳不整合面200m范围内的岩溶缝洞系统中。勘探成果表明,长期发育的继承性古隆、丰富的多油源供给、强烈非均质性的岩溶-缝洞型储层及优良的储盖配置、多层次和多类型圈闭的广泛发育、以及由岩溶缝洞-断裂-不整合面组成的疏导体系,是形成塔河大型油气田的重要条件。 相似文献
922.
胶东栖霞东北部地区处于挤压与拉伸并存的地球动力学环境,发育韧-脆性剪切带,NE-NNE向新型,层间滑动断层3种构造类型,控制着韧性剪切带型,微细浸浸型,层间滑动角砾岩型金矿化的产出,根据成矿地质条件,划分出藏家庄盆地周边和金山-庙后地区两个成矿预测区,有望取得找矿突破。 相似文献
923.
The discrete‐time variable structure control method for seismically excited linear structures with time delay in control is investigated in this paper. The control system with time delay is first discretized and transformed into standard discrete form which contains no time delay in terms of the time delay being integer and non‐integer times of sampling period, respectively. Then the discrete switching surface is determined using ideal quasi‐sliding mode and discrete controller is designed using the discrete approach‐law reaching condition. The deduced controller and switching surface contain not only the current step of state feedback but also linear combination of some former steps of controls. Numerical simulations are illustrated to verify the feasibility and robustness of the proposed control method. Since time‐delay effect is incorporated in the mathematical model for the structural control system throughout the derivation of the proposed algorithm, system performance and dynamic stability are guaranteed. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
924.
John P. Wolf 《地震工程与结构动力学》2002,31(1):15-32
The scaled boundary finite‐element method is a powerful semi‐analytical computational procedure to calculate the dynamic stiffness of the unbounded soil at the structure–soil interface. This permits the analysis of dynamic soil–structure interaction using the substructure method. The response in the neighbouring soil can also be determined analytically. The method is extended to calculate numerically the response throughout the unbounded soil including the far field. The three‐dimensional vector‐wave equation of elasto‐dynamics is addressed. The radiation condition at infinity is satisfied exactly. By solving an eigenvalue problem, the high‐frequency limit of the dynamic stiffness is constructed to be positive definite. However, a direct determination using impedances is also possible. Solving two first‐order ordinary differential equations numerically permits the radiation condition and the boundary condition of the structure–soil interface to be satisfied sequentially, leading to the displacements in the unbounded soil. A generalization to viscoelastic material using the correspondence principle is straightforward. Alternatively, the displacements can also be calculated analytically in the far field. Good agreement of displacements along the free surface and below a prism foundation embedded in a half‐space with the results of the boundary‐element method is observed. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
925.
山西离柳地区生态地球化学环境中氟与人群健康关系的研究 总被引:3,自引:0,他引:3
为了研究不同生态地球化学区内元素对人体健康的影响 ,在山西离柳地区西部 ,以氟为例 ,运用地下水化学热力学、化学动力学及统计分析 ,得出 :(1)地氟病患病率及病情轻重程度 ,与水 (土 )中F-总量 (F总)及活度 (aF- )、络合物活度 (aMF)及其饱和指数 (βMF)呈正相关关系 ,符合一般规律 ;(2 )氟的不同存在形态的致病作用是aF- >F总 ,aNaF0 >aCaF+>aMgF+,βNaF0 >βCaF+>βMgF+;(3)水循环交替条件及有关组分含量与病情轻重密切相关。研究结果为防治地氟病和地方性病症提供了定性、定量依据 ,也为同类研究提出了新的途径 相似文献
926.
927.
两相介质动力学问题的研究进展 总被引:6,自引:2,他引:6
本回顾了两相多孔介质研究的历史,包括基本运动微分方程,两相介质中弹性波的传播性质,两相介质动力问题的解析方法及数值方法,以及数值方法中涉及的人工边界条件,并指出其中存在的问题和今后值得研究的方向。 相似文献
928.
Geochemistry of Late Permian to Early Triassic pelagic cherts from southwest Japan: implications for an oceanic redox change 总被引:4,自引:0,他引:4
Major, trace, and rare earth element abundances were determined for the southwestern Japanese pelagic chert sequence from the early Late Permian to early Early Triassic to investigate a redox change in deep-sea pelagic environments before and at the Permo-Triassic boundary (PTB) (251 Ma). The sequence was primarily deposited in the deep-sea of the superocean Panthalassa, and then was accreted to Japan in the Middle Jurassic. A remarkable lithostratigraphic change from red chert to siliceous∼carbonaceous claystone through gray chert is observed in this sequence. Constituent elements for these sedimentary rocks are essentially derived from two sources: (1) an ancient seawater via biogenic (mainly radiolarian), hydrothermal, and authigenic materials and (2) an average shale-like terrigenous material. The present measurement demonstrates significant stratigraphic changes of the Ce/Cenon-ter* value (estimated Ce anomaly value of non-terrigenous component, recalculated by subtraction of terrigenous REEs from bulk REEs) and the (Mn/TE)sample/(Mn/TE)PAAS value (excess Mn component other than terrigenous one; TE=terrigenous elements including Ti, Al, Nb, Hf, Th; PAAS=Post-Archean Average Australian Shale) in the Permian chert. The Ce/Cenon-ter* values increase from <0.2 to 1 and the (Mn/TE)sample/(Mn/TE)PAAS values decrease up-section, suggesting that the redox condition of deep-sea open-ocean changed from oxic to suboxic in an interval of approximately 10 Myr. The (∑Fe/TE)sample/(∑Fe/TE)PAAS and (Mn/TE)sample/(Mn/TE)PAAS values of carbonaceous claystone near or at the PTB are less than unity, suggesting that reductive dissolution of iron and manganese occurred under an anoxic condition. This supports the idea of the PTB oceanic anoxia in the superocean Panthalassa. The present data suggest that the anoxic condition prevailed in the deep-sea pelagic regions for an extremely long period, much more than 10 Myr, from the middle Late Permian to early Early Triassic. This long-term development of widespread oceanic anoxia may have been linked to the greatest mass extinction of the Phanerozoic. 相似文献
929.
930.