A non-linear regularized constrained impedance inversion     

Hongbing Zhang  Zuoping Shang  Changchun Yang 《Geophysical Prospecting》2007,55(6):819-833

Inversion for seismic impedance is an inherently complicated problem. It is ill‐posed and band‐limited. Thus the inversion results are non‐unique and the process is unstable. Combining regularization with constraints using sonic and density log data can help to reduce these problems. To achieve this, we developed an inversion method by constructing a new objective function, including edge‐preserving regularization and a soft constraint based on a Markov random field. The method includes the selection of proper initial values of the regularization parameters by a statistical method, and it adaptively adjusts the regularization parameters by the maximum likelihood method in a fast simulated‐annealing procedure to improve the inversion result and the convergence speed. Moreover, the method uses two kinds of regularization parameter: a ‘weighting factor’λ and a ‘scaling parameter’δ. We tested the method on both synthetic and field data examples. Tests on 2D synthetic data indicate that the inversion results, especially the aspects of the discontinuity, are significantly different for different regularization functions. The initial values of the regularization parameters are either too large or too small to avoid either an unstable or an over‐smoothed result, and they affect the convergence speed. When selecting the initial values of λ, the type of the regularization function should be considered. The results obtained by constant regularization parameters are smoother than those obtained by adaptively adjusting the regularization parameters. The inversion results of the field data provide more detailed information about the layers, and they match the impedance curves calculated from the well logs at the three wells, over most portions of the curves.  相似文献   

Tests and applications of an approach to absorbing reflected waves towards incident boundary     

张洪生  王炎  许春辉  商辉  于小伟 《中国海洋工程》2013,27(6):703-718

If the upstream boundary conditions are prescribed based on the incident wave only, the time-dependent numerical models cannot effectively simulate the wave field when the physical or spurious reflected waves become significant. This paper describes carefully an approach to specifying the incident wave boundary conditions combined with a set sponge layer to absorb the reflected waves towards the incident boundary. Incorporated into a time-dependent numerical model, whose governing equations are the Boussinesq-type ones, the effectiveness of the approach is studied in detail. The general boundary conditions, describing the down-wave boundary conditions are also generalized to the case of random waves. The numerical model is in detail examined. The test cases include both the normal one-dimensional incident regular or random waves and the two-dimensional oblique incident regular waves. The calculated results show that the present approach is effective on damping the reflected waves towards the incident wave boundary.  相似文献   

Brief Analysis on the Reason of Exceptive Frost     

Shang Zhengqiang 《山西气象》2008,(3)

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宁阳县蒋集镇水库土坝非稳定性探析     

张修脉  尚海明 《山东国土资源》2007,23(6):2007/4/9-2007/6/20

宁阳县蒋集镇地处汶河南岸，黄淮分水岭北侧，最大海拔高程361m.全镇区域面积12．7万km^2，其中山区、丘陵占2／3，岩石类型以花岗片麻岩为主。20世纪50-60年代兴建了117座水库塘坝，其中小（一）型水库2座，小（二）型水库15座，塘坝100座，总库容1700余万m^2，坝体以土坝为主。由于当时施工机械落后，技术有限，经费不足，造成工程质量较低，因而不少土坝产生渗流、流土、管涌、滑坡等现象。  相似文献   

东营市东营区实施城区村居改造集约利用城市土地          下载免费PDF全文

刘建强  赵云秀  商述珍 《山东国土资源》2007,23(2):20-21

近年来,在市委、市政府的正确领导下,东营区按照“统一规划、合理布局、综合开发、配套建设”的原则,积极推进城区村居改造建设,促进了城市土地的节约集约利用。1加强组织领导强力保证村居改造工作东营市是在石油矿区基础上发展起来的新兴城市,受过去“随矿建镇”模式的影响,中心城建设布局分散,土地利用粗放,特别是有18个村居散落在城区之内,环境质量差,基础设施不配套,浪费了土地资源,影响了城市化进程。为充分发挥土地资源效益,促进城市和谐发展,该区把城区村居改造工作摆上了重要议事日程,明确目标责任,实行重点调度,在人力、物力、财力…  相似文献   

Distinction and grain-size characteristics of intertidal heterolithic deposits in the middle Qiantang Estuary (East China Sea)   总被引：1，自引：0，他引：1  

Daidu Fan  Shuai Shang  Guofu Cai  Junbiao Tu 《Geo-Marine Letters》2015,35(3):161-174

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The influence of turbulent mixing on the subsurface chlorophyll maximum layer in the northern South China Sea     

Shang  Chenjing  Liang  Changrong  Chen  Guiying  Gao  Yongli 《中国海洋湖沼学报》2021,39(6):2167-2180

Journal of Oceanology and Limnology - We present observations from deployments of turbulent microstructure instrument and CTD package in the northern South China Sea from April to May 2010. From...  相似文献   

老工业区产业结构转型与用地结构转型互动机制及优化路径——以上海市宝山区为例   总被引：1，自引：0，他引：1  

尚勇敏  曾刚 《地域研究与开发》2014,(5)

尝试理清老工业区产业结构转型与用地结构转型内涵,提出其转型效率的函数表达,分析二者间的互动关系;并运用改进的动态变化度及偏离系数,对上海市宝山区进行实证研究。结果表明:(1)宝山区产业结构与用地结构变化度逐渐增加,工业和第三产业动态度分别由1996年的2.48%和5.36%上升至2012年的4.75%和5.51%,用地结构动态度由11.16%上升至13.53%;(2)宝山区三次产业结构总体趋于优化,但产业内部并未优化,仍以重化工业和传统服务业为主导;(3)宝山区用地结构与产业结构不协调并处于加剧的状态。老工业区产业结构与用地结构存在较强的互动关系,改进的动态变化度及偏离系数方法为老工业区产业结构转型与用地结构转型问题提供了一种研究思路。提出宝山区产业结构转型与用地结构转型的优化路径。  相似文献   

基于遗传小波神经网络的海底声学底质识别分类   总被引：4，自引：3，他引：1  

熊明宽  吴自银  李守军  尚继宏 《海洋学报》2014,36(5):90-97

分割海底声纳探测图像,提取单元特征向量进行主成份分析,选取均值、标准差、对比度、相关系数、能量及同质性作为训练特征向量,构建小波神经网络。利用遗传算法优化小波神经网络的初始权值及小波参数,对砂、礁石、泥3种底质类型分别进行训练,并得到3种底质的测试精度都在90%以上,优于单独利用小波神经网络进行训练时的测试精度,克服了小波神经网络训练时易陷入局部极小的固有缺陷,表明基于遗传算法的小波神经网络可有效用于海底底质声纳图像的识别和分类。  相似文献   

琼东南盆地深水区断层垂向输导及成藏模式   总被引：2，自引：1，他引：1  

王振峰  刘震  曹尚  孙志鹏  左倩媚  王亚辉  何卫军 《海洋学报(英文版)》2014,33(12):96-106

In the Qiongdongnan Basin, faults are well developed.Based on the drilling results, the traps controlled two or more faults are oil-rich. However, when only one fault cut through the sand body, there is no sign for hy-drocarbon accumulation in the sandstone. In terms of this phenomenon, the principle of reservoir-forming controlled by fault terrace is proposed, i.e., when the single fault activates, because of the incompressibility of pore water, the resistance of pore and the direction of buoyancy, it is impossible for hydrocarbon to ac-cumulate in sandstone. But when there are two or more faults, one of the faults acts as the spillway so the hydrocarbon could fill in the pore of sandstone through other faults. In total five gas bearing structures and four failure traps are considered, as examples to demonstrate our findings. According to this theory, it is well-advised that south steep slope zone of Baodao-Changchang Depression, south gentle slope zone of Lingshui Depression, north steep slope zone of Lingshui Depression, and north steep slope zone of Baodao Depression are the most favorable step-fault zones, which are the main exploration direction in next stage.  相似文献