高精度地震时深转换方法研究及应用     

徐立恒  鲜波  薛玉英  李彦斌 《吉林大学学报(地球科学版)》2014,44(5):1712-1719

地震体的时深转换是利用地震资料进行构造及储层解释的一个非常关键的环节,而常规时深转换方法精度较低,一定程度上影响了勘探井位布置及开发方案的制定。采用时深一体化网格方法,即顶底界面以多井合成记录标定求取的平面时深关系为准,顶底之间利用时间域和深度域网格一一对应关系进行“物理”搬运的方法,从而减小转换前后的累计误差,使地震体及地震反演体时深转换前后的波形与砂体形态保持一致。利用该方法将喇嘛甸油田北部区块反演结果转换到深度域,精细刻画了断层附近砂体的分布特征,指导了L213等3口水平井的部署,砂体预测准确率达到98%以上,年增油17 000 t,展现了新的时深转换方法的精度及可靠性。  相似文献   

基于地理加权回归的漫湾库区景观破碎化及影响因子分析   总被引：2，自引：0，他引：2  

刘世梁  刘琦  王聪  赵清贺  邓丽  董世魁 《地理科学》2014,34(7):856-862

应用地理加权回归模型分析漫湾库区景观破碎化指数——有效筛网大小与相关因子之间的空间关系。选取的解释变量分别是距道路的距离、距乡村的距离、距河流的距离、坡度。结果表明：大坝修建后4种解释变量与有效筛网大小呈现较显著的正相关性。与线性回归模型相比,地理加权回归模型的拟合效果显著提高。1974~1988年,有效筛网大小对各影响因子最敏感的区域面积呈现显著的时空变化这为确定水电站建设及其他因素对景观破碎化影响的大小,并进一步改善库区景观破碎化的现状提供了依据。  相似文献   

天山中东段地震层析成像的初步研究          下载免费PDF全文

罗炬  李志海  王海涛 《地震工程学报》2014,36(1):107-113,169

以中国境内天山中东段为研究区域,选定新疆地震台网自2001年以来近10年的P波和S波震相,对研究区域网格化,反演了地壳P波速度结构。结果表明：地壳中成像分辨率较高,高低速分布明显,天山中东段莫霍面埋深在48～60 km内变化,其中,中天山莫霍面最深,北天山莫霍面最浅;莫霍面起伏最大的地方往往位于盆山交汇处。  相似文献   

面向GTP的三维地质模型空间剖切方法与应用     

马钧霆  陈锁忠  何志超  戴金晖 《地球信息科学学报》2015,17(2):153-159

广义三棱柱（GTP）是近年来提出并被广泛应用于三维地质建模领域的一种较为成熟的空间数据模型,可满足大多数地质钻孔数据的三维地质建模的要求。然而,现有针对GTP模型的三维空间剖切分析方法,仍无法适用于偏斜钻孔数据所建三维地质模型高效多次任意剖切、不能支持较为复杂的地质模型空间分析的问题。本文通过对GTP剖切算法改进研究,提出了采用动态四面体剖分法减小数据冗余;鉴于GTP形态较为复杂,可对剖切后保留多面体进行拓扑关系的重组,解决任意多次剖切问题;将多次“面-体”形式的单剖切运算组合为一次“体-体”形式的复合剖切运算的方法,可高效实现对三维地质模型空间分析。本文着重面向GTP体元的多重任意切剖平面的剖切问题,在分析了GTP体元特征的基础上,弥补了三维地质建模领域中对GTP体元任意、多重剖切方法研究的不足。应用实例表明,上述改进算法可以提高GTP剖切计算速度,并能够快速实现巷道掘进模拟,以及空间开挖模拟等复杂的空间分析功能。  相似文献   

三角谱元法及其在地震正演模拟中的应用   总被引：2，自引：2，他引：0       下载免费PDF全文

李琳  刘韬  胡天跃 《地球物理学报》2014,57(4):1224-1234

谱元法（SEM）是基于有限元（FEM）的一种算法,在地震正演模拟中应用广泛,但是大部分研究都是基于四边形网格下的谱元法.本文给出了2阶谱元法在三角网格中（TSEM）的基本原理,包括Lagrange形函数的构建,数值积分公式的选取.在此基础上,分析了2阶TSEM方法的数值频散特性以及稳定性条件,并引入三角网格下3阶有限元方法进行分析对比,数值算例的结果证明2阶TSEM相比于3阶FEM具有更高的计算精度,以及更宽松的稳定条件.最后,本文将TSEM方法应用于中国西部地区的两个含溶洞介质的地质模型中,数值模拟结果表明TSEM方法能够有效地模拟复杂结构的介质,有助于对地震波场传播特性的认识.  相似文献   

A Variable Mesh Spacing for Large-Eddy Simulation Models in the Convective Boundary Layer     

Gervásio Annes Degrazia  Umberto Rizza  Franciano Scremin Puhales  Antônio Gledson Goulart  Jonas Carvalho  Guilherme Sausen Welter  Edson Pereira Marques Filho 《Boundary-Layer Meteorology》2009,131(2):277-292

A variable vertical mesh spacing for large-eddy simulation (LES) models in a convective boundary layer (CBL) is proposed. The argument is based on the fact that in the vertical direction the turbulence near the surface in a CBL is inhomogeneous and therefore the subfilter-scale effects depend on the relative location between the spectral peak of the vertical velocity and the filter cut-off wavelength. From the physical point of view, this lack of homogeneity makes the vertical mesh spacing the principal length scale and, as a consequence, the LES filter cut-off wavenumber is expressed in terms of this characteristic length scale. Assuming that the inertial subrange initial frequency is equal to the LES filter cut-off frequency and employing fitting expressions that describe the observed convective turbulent energy one-dimensional spectra, it is feasible to derive a relation to calculate the variable vertical mesh spacing. The incorporation of this variable vertical grid within a LES model shows that both the mean quantities (and their gradients) and the turbulent statistics quantities are well described near to the ground level, where the LES predictions are known to be a challenging task.  相似文献   

抛弃式探头下沉运动数值计算的网格划分方法研究     

陈振涛  刘凤  王晓蕾  叶松 《海洋技术学报》2017,36(5):35-40

各类抛弃式探头下沉运动的数值计算研究都需要对探头表面和整个计算域进行网格划分的前处理过程,选择不同的网格划分方法和划分精度,会影响数值计算速度和计算精度,最终生成的网格质量决定了计算结果的收敛性和准确性。针对抛弃式探头的复杂结构,对比了两种网格划分方法、三种网格划分精度,完成探头计算区域的网格划分,采用k-ε湍流模型,进行抛弃式探头下沉运动的数值计算,并将计算结果与水箱和水库实验结果进行对比,验证了混合网格划分方法和普通精度网格对抛弃式探头下沉运动数值计算的适用性,研究结果对类似较为复杂结构的水下运动体的数值计算前处理过程具有一定的参考和借鉴意义。  相似文献   

Influence of Reinforcement Mesh Configuration for Improvement of Concrete Durability     

PAN Chong-gen  JIN Wei-liang  MAO Jiang-hong  ZHANG Hu  SUN Li-hao  WEI Dong 《海洋工程》2017,31(5):631-638

Steel bar in concrete structures under harsh environmental conditions, such as chlorine corrosion, seriously affects its service life. Bidirectional electromigration rehabilitation (BIEM) is a new method of repair technology for reinforced concrete structures in such chloride corrosion environments. By applying the BIEM, chloride ions can be removed from the concrete and the migrating corrosion inhibit can be moved to the steel surface. In conventional engineering, the concrete structure is often configured with a multi-layer steel mesh. However, the effect of the BIEM in such structures has not yet been investigated. In this paper, the relevant simulation test is carried out to study the migration law of chloride ions and the migrating corrosion inhibitor in a concrete specimen with complex steel mesh under different energizing modes. The results show that the efficiency of the BIEM increases 50% in both the monolayer steel mesh and the double-layer steel mesh. By using the single-sided BIEM, 87% of the chloride ions are removed from the steel surface. The different step modes can affect the chloride ion removal. The chloride ions within the range of the reinforcement protective cover are easier to be removed than those in the concrete between the two layers of steel mesh. However, the amount of migrating corrosion inhibitor is larger in the latter circumstances.  相似文献   

浅埋隧道掌子面稳定性二维自适应上限有限元分析     

阳军生  张箭  杨峰 《岩土力学》2015,36(1):257-264

为研究浅埋隧道掌子面稳定性及获取精细化的破坏模式,提出了一种上限有限元非结构化网格自适应加密策略。以单元耗散能权重指标作为网格自适应加密评判准则,该策略同时兼顾了单元尺度与塑性应变。应用高阶的6节点三角形单元并建立上限有限元线性规划模型,以多次反复计算和网格加密的方式实现了二维自适应上限有限元分析并编制了计算程序。利用条形基础地基极限承载力课题,从上限解精度和网格加密形态方面验证了该程序的有效性。针对浅埋隧道掌子面稳定性问题,展开多参数条件下的自适应上限有限元计算,分析了网格加密过程中单元总数与上限解精度的关系,列出不同隧道埋深和内摩擦角对应的隧道掌子面稳定性临界值的上限解,揭示出掌子面稳定性变化规律及精细化的破坏模式。  相似文献   

McMurdo sound hydrological observations, 1972–73     

A. E. Gilmour 《新西兰海洋与淡水研究杂志》2013,47(1):75-95

Hydrological data, including current observations, from a line of five stations across seasonal ice in McMurdo Sound, Antarctica, are presented. The observations, which were made during the 1972–73 summer, gave evidence for a net flux of approximately 0.4 × 10⁶m³.s^‐1 flowing towards the south to pass under the Ross Ice Shelf. There was a small northward flux (0.04 × 10⁶m³.s^‐1) on the western side of the sound, but over most of the width the flow was to the south.

Diurnal tidal currents, which were analysed in terms of K1, P1, and O1 components, were superposed on the drift currents.

Temperature and salinity measurements revealed signs of surface water dilution and warming down to 200 m in the region of southerly drift. Temperatures associated with the northerly drift on the western side of the section were close to freezing at all depths. This water can be identified as coming from under the Ross Ice Shelf.  相似文献