致密砂岩储层速敏效应形成机理及其分布规律研究——以库车坳陷东部阿合组为例   总被引：1，自引：0，他引：1       下载免费PDF全文

袁文芳  秦红  王锋  曹少芳  邢星 《地质科学》2014,49(4):1279-1286

库车坳陷东部下侏罗统阿合组是典型的致密储层,由于储层自身（特）低孔（特）低渗的物性特征,极易引发较强的敏感性。本文通过岩石薄片和扫描电镜的显微观察,结合X衍射测试分析和致密储层敏感性流动实验评价,从运移微粒的成因、 含量和孔喉特征等角度,分析了研究区产生速敏效应的内在因素; 结合速敏效应的实验评价,梳理引发研究层段速敏效应平面差异的主控因素,认为研究层段内广泛发育由刚性颗粒崩解而形成微小颗粒的含量以及孔喉大小和连通性好坏,是造成上述速敏效应平面差异的主控因素。通过对研究区速敏效应形成机理的具体分析和评价,为下一步的钻探和开采提供了切实可行的储层保护和改造建议。  相似文献   

区域中尺度模式云微物理参数化方案特征及其在中国的适用性   总被引：3，自引：0，他引：3  

尹金方  王东海  翟国庆 《地球科学进展》2014,29(2):238-249

云微物理参数化方案在数值模式中起着重要的作用,是影响数值天气预报和气候预测准确性的最大因素。系统回顾了中尺度数值模式中云微物理参数化方案的研究进展,并统计分析了最近十余年云微物理参数化方案在中国范围内的敏感性试验研究成果。Lin方案和Rutledge-Hobbs方案奠定了中尺度模式中云微物理参数化方案的基础,其他方案都是直接或间接在这2个方案的基础上从多方面改进而形成的。这些改进主要体现在:①水凝物粒子分类数目;②冰核活化;③粒子谱分布描述函数;④粒子谱截距的取值;⑤粒子间相互转换阈值大小的设定。中国范围内云微物理参数化方案敏感性试验研究成果统计表明,使用WRF模式中Lin方案的模拟效果较好,MM5模式采用Goddard和Reisner方案效果较好。  相似文献   

太阳射电望远镜的灵敏度与天线口径关系的分析     

丁祖高  黄光力 《紫金山天文台台刊》1993,12(1):60-64

  相似文献   

Anatomy of a closing window: Vulnerability to changing seasonality in Interior Alaska   总被引：1，自引：0，他引：1  

Shannon M. McNeeley  Martha D. Shulski 《Global Environmental Change》2011,21(2):464-473

Alaska is among the fastest warming places on Earth, and the Interior region is warming the most statewide. Significant regional-scale ecosystem services disruptions are affecting Alaska Natives’ subsistence hunting and harvest success. The well-being of rural native communities is still highly dependent on access and ability to harvest wild foods such as salmon and moose (Alces alces gigas) among many others. Over the last decade communities in the Koyukuk-Middle Yukon (KMY) region of Interior Alaska report an inability to satisfy their needs for harvesting moose before the hunting season closes, citing warmer falls, changing precipitation and water levels, and the regulatory framework as primary causes. Through the integration of ethnographic methods to record indigenous observations and understanding of climate (IC) with analysis of meteorological data, we provide a comprehensive picture of vulnerability to recent warming trends in the Koyukuk-Middle Yukon region of Interior Alaska, one that captures more than statistical analysis of “norms” can provide. We will demonstrate how low exposure resulting in a small shift in seasonality has truly socially significant effects to people “on the ground” when community sensitivity is high because of the convergence of multiple social-ecological stressors. In this case, a seemingly small climatic exposure when combined with high social-ecological system sensitivity results in vulnerability to this climate change-related seasonality shift because of: (a) the effects on moose and the social-ecological dynamics of the system, and (b) the importance of this time of the year to meeting annual subsistence needs.  相似文献   

Transient analysis for fluid injection into a dome reservoir     

Chia-Chen Kuo  Ching-Sheng HuangHund-Der Yeh 《Advances in water resources》2011,34(12):1553-1562

A dome-shaped layer can be selected as a storage site for fluid injection. In this study, we develop a mathematical model for simulating transient head distribution in a heterogeneous and anisotropic dome-shaped layer due to a constant-head injection in a fully penetrating well. In the model, a form of step change is adopted to approximate the upper and lower boundaries of the dome and then the layer is split into two regions. The Laplace-domain solution of the model is developed using the Laplace transform and method of separation of variables. The transient injection rate at wellbore can then be obtained based on Darcy’s law and Bromwich integral method. The predicted head contours from the head solution show significant vertical flow components near the location of step change in the dome reservoir. The results of sensitivity analysis indicate that the hydraulic conductivity is the most sensitive parameter and the specific storage is the least sensitive one to the injection rate after a short period of injection time. In addition, the injection rate for a dome reservoir is also very sensitive to the change of the height for the reservoir near the injection well (first region) at a very early injection time. In contrast, the injection rate is more sensitive to the change of the height of the second region than that of the first region at late time. This analytical solution may be used as a primary tool to assess the capacity of fluid injection to various dome reservoirs.  相似文献   

广州人为热初步估算及敏感性分析   总被引：5，自引：0，他引：5  

王志铭  王雪梅 《气象科学》2011,31(4):422-430

考虑了工业、交通和生活三种人为热排放源,利用广州市工业和生活能源消耗量、汽车保有量、主干道车流量等数据,估算出广州人为热日变化排放通量,全天平均排放通量411 W〖DK〗·m-2,最大排放通量出现在11时,为723 W ·m-2,其中工业排放占总排放量686%。利用耦合到WRF中的单层城市冠层模式(WRF/UCM),对人为热作用进行敏感性试验,包括无人为热、无日变化人为热、有日变化人为热、人为热排放通量翻倍四种方案。结果显示,方案之间冠层感热通量的差异与人为热设置的差异大致相等。试验方案之间冠层内气温差异较小,单倍人为热与双倍人为热的最大差值约只有02℃。另外,人为热使湍流得到发展,双倍人为热比单倍人为热湍流动能增加约01~04 m2 ·s-2。且人为热对白天城市边界层湍涡有增强作用,添加单倍人为热后使气流垂直速度最大增加可达01 m ·s-1,使垂直混合加强。有日变化的人为热对热岛强度的贡献在中午时最大,单倍人为热的平均贡献率159%,双倍人为热为228%;而无日变化的人为热在凌晨时贡献最大,平均贡献率149%。  相似文献   

两次暴雨过程模拟对陆面参数化方案的敏感性研究   总被引：1，自引：0，他引：1  

陈海山  倪悦  苏源 《气象学报》2014,72(1):79-99

选取发生在江西和福建境内的两次暴雨个例,利用NCEP再分析资料在对暴雨发生前、后的环境场和物理量场进行诊断和对比分析的基础上,采用中尺度模式WRF V3.3,通过数值模拟探讨了陆面过程对两次暴雨过程的可能影响及其相关的物理过程。结果表明,2012年5月12日江西大暴雨主要受大尺度环流和中尺度天气系统影响,具有范围大、持续时间长等特点,属于大尺度降水为主的暴雨;而2011年8月23日福建暴雨发生在副热带高压控制下的午后,局地下垫面强烈的感热和潜热通量使低层大气不稳定性增强,触发了此次对流性降水为主的暴雨。通过资料诊断分析,可以判断陆面过程对福建暴雨个例的影响程度明显强于江西暴雨个例。通过关闭地表通量试验发现,陆面过程对暴雨模拟十分重要,尤其是对于该个例中对流性降水的发生起到关键性的作用。通过陆面参数化方案的敏感性试验发现,两次暴雨过程对陆面参数化方案均较为敏感。江西暴雨对陆面过程的敏感性主要体现在对流降水的模拟上,而福建暴雨则体现在大尺度降水的模拟方面,即福建暴雨对陆面参数化方案的敏感性强于江西暴雨。敏感性产生机制与降水类型关系紧密,大尺度降水对陆面过程的敏感性主要来源于不同参数化模拟的中高空对流系统的差异,而对流降水的敏感性则与不同参数化模拟的地表通量的差异有关。通过陆面参数的扰动试验进一步发现,相比于地表粗糙度和最小叶孔阻抗,土壤孔隙度和地表反照率则是影响对流降水对陆面过程敏感的关键因子,这在本质上与地表通量是否受到扰动有关。地表通量较风场而言,受扰动引起变化的空间范围广、时间响应快,变化具有明显规律性。所得结果可为深入理解陆面过程影响暴雨等天气过程和改进数值模式对暴雨的模拟能力提供一定的参考。  相似文献   

Geospatial scenario based modelling of urban and agricultural intrusions in Ramsar wetland Deepor Beel in Northeast India using a multi-layer perceptron neural network     

《International Journal of Applied Earth Observation and Geoinformation》2014

In recent decades, the world has experienced unprecedented urban growth which endangers the green environment in and around urban areas. In this work, an artificial neural network (ANN) based model is developed to predict future impacts of urban and agricultural expansion on the uplands of Deepor Beel, a Ramsar wetland in the city area of Guwahati, Assam, India, by 2025 and 2035 respectively. Simulations were carried out for three different transition rates as determined from the changes during 2001–2011, namely simple extrapolation, Markov Chain (MC), and system dynamic (SD) modelling, using projected population growth, which were further investigated based on three different zoning policies. The first zoning policy employed no restriction while the second conversion restriction zoning policy restricted urban-agricultural expansion in the Guwahati Municipal Development Authority (GMDA) proposed green belt, extending to a third zoning policy providing wetland restoration in the proposed green belt. The prediction maps were found to be greatly influenced by the transition rates and the allowed transitions from one class to another within each sub-model. The model outputs were compared with GMDA land demand as proposed for 2025 whereby the land demand as produced by MC was found to best match the projected demand. Regarding the conservation of Deepor Beel, the Landscape Development Intensity (LDI) Index revealed that wetland restoration zoning policies may reduce the impact of urban growth on a local scale, but none of the zoning policies was found to minimize the impact on a broader base. The results from this study may assist the planning and reviewing of land use allocation within Guwahati city to secure ecological sustainability of the wetlands.  相似文献   

横向各向同性地层中随钻声波测井模式波分析   总被引：8，自引：6，他引：2       下载免费PDF全文

李希强  陈浩  何晓  王秀明  丛健生 《地球物理学报》2013,56(9):3212-3222

针对横向各向同性地层随钻声波测井模型,通过模式分析的方法,考察了快速地层和慢速地层井孔内随钻单极子、偶极子和四极子声源激发的斯通利波、弯曲波和螺旋波的相速度频散和激发强度特征,计算了这些模式波对于地层弹性常数的灵敏度,并与电缆测井中的情况进行了比较.结果表明:随钻斯通利波在低频时对地层弹性常数中c₆₆的灵敏度较电缆测井中有了很大提高,可用于反演地层水平向横波速度;随钻偶极子最低阶弯曲波在低频时不能用于直接获取地层横波信息,但在慢速地层中频率较高(例如6 kHz)时却可以间接得到地层垂直向横波速度;随钻四极子螺旋波的特征与电缆测井中的类似,可用于获取地层垂直向横波速度.  相似文献   

Stochastic strong ground motion simulations in sparsely-monitored regions: A validation and sensitivity study on the 13 March 1992 Erzincan (Turkey) earthquake     

《Soil Dynamics and Earthquake Engineering》2013

Stochastic simulations have recently become quite popular for estimating synthetic ground motion time histories. For seismically active regions that are not well-monitored or studied extensively, input parameters of the simulations should be carefully selected as the reliability of the simulation results directly depends on the accuracy of the input parameters. In the first part of this study, 13 March 1992 Erzincan (eastern Turkey) earthquake (Mw=6.6), which is recorded at only three strong ground motion stations, is simulated using the stochastic finite-fault method. The source and regional path parameters for this event are adopted from previously validated studies whereas the local site parameters are derived herein. In the second part of the paper, sensitivity of the simulation results with respect to small changes in selected input seismic parameters is investigated. The parameters for which sensitivities are computed include stress drop, crustal shear-wave quality factor and kappa operator. A change of 20% in stress drop value results in 14% change in PGA, whereas a 20% difference in the Q₀ value causes 17% change in PGA, and a 20% variation in kappa leads to 15% difference in PGA. Numerical experiments presented in this study prove that the ground motion simulations are prone to trade-off between the source, path and site filters. Hence, input models must be implemented carefully for reliable synthetic ground motions.  相似文献