Spatial variability in petrophysical properties in Upper Maastrichtian chalk outcrops at Stevns Klint, Denmark     

Peter Frykman   《Marine and Petroleum Geology》2001,18(10)

The spatial variability of porosity and permeability was determined for a section in the uppermost Maastrichtian chalk exposed in the Sigerslev quarry at Stevns Klint. The aims were threefold: (1) to quantify the spatial variability pattern and its link to geology by applying systematic variogram analysis procedure, (2) to detect potential cyclicity in the petrophysical properties in this pure and overtly homogeneous chalk, and (3) to compare the section with chalk reservoirs in the North Sea in order to asses to what extent this onshore sequence has a potential as an analogue of the offshore, more deeply buried chalk reservoirs. The interval is of comparable stratigraphic age to the uppermost reservoir zones in the Tor Formation of the North Sea chalk reservoirs. The variability and spatial correlation of porosity and permeability in both horizontal and vertical directions are interpreted in a geological context and show indications of small-scale heterogeneity at 15–25 cm scale, but the clear cyclic layering described from other chalk deposits is not recognised at this locality. The investigated outcrop is not a close analogue to North Sea reservoir chalk, but some aspects are common including basic material properties, porosity/permeability trends and the variability pattern. The outcrop has a potential as analogue for some of the onshore subsurface chalk successions at shallow burial depth that form important aquifers.  相似文献   

关于具二次约束最小二乘问题的敏度分析     

刘新国 《中国海洋大学学报(自然科学版)》1996,(2)

本文系统地研究具二次约束最小二乘问题的敏度分析。首先给出长期方程唯一正根的上界和下界；然后证明割线法用于计算拉格朗日乘子时全局收敛；最后给出解的扰动界。  相似文献   

极谱法在镉诱导单胞藻和禾草类植物螯合物研究的应用     

周莲贞  尼贝日 《台湾海峡》1995,14(1):15-21

三角褐指藻（Phaeodactylum tricornutum）和翦股颖草属禾草（A-grostis capillaris）经过处理后再用液相层析法从中提取一种金属结合多肽，极谱分析表明不同的镉结合多肽具有不同的稳定性，金属结合与金属硫蛋白不同，在电位--1.7V附近未出现氧催化峰，金属硫蛋白以及从单胞藻和禾草中提取的多肽在极谱测定过程中都在电位-520mV和-930mV附近出现双峰，在-520mV处，半波电位显示了单个镉硫醇键的还原，在-930mV处的峰是由于镉和硫多齿螯合的还原，因此这通常可用以鉴定镉螯合物。在镉浓度为5umol/dm^3和10umol/dm^3时-930mV的峰高与镉浓度之间存在着对应关系。  相似文献   

Numerical Analysis of Wave Forces on Arbitrarily Shaped Multi-Pillars Over Varying Topography     

Zhang Libang Research Engineer  First Institute of Oceanography  Qingdao 《中国海洋工程》1991,(4)

The modified hybrid element method (MHEM) is utilized to predict and analyze wave forces on arbitrarily shaped multiple bodies. This method can be applied to waves of all water depths, i. e. shallow, intermediate, and deep waters, on slowly varying seabed. The MHEM employs the ICCG method to save CPU and storage, thus the computation of wave forces for large multi-body systems can be carried out on microcomputers. Numerical results of the present method are compared with experimental data and other solutions. It is shown that the MHEM provides more accurate solutions of the wave forces than other numerical methods do. Therefore, the methodology presented herein can be used in the design of coastal and ocean structures.  相似文献   

珠江口外陆架表层沉积物的地球化学分区     

周蒂  陈绍谋  陈汉宗 《热带海洋学报》1991,(3)

根据249个表层沉积物样品的Ca,Al,N,P,Mg,Fe,Mn,Ti和有机碳的测定数据,利用稳健RQ型主分量分析及Q型聚类分析方法,对珠江口外陆架表层沉积物进行了地球化学分类,并将该陆架区划分成陆源细碎屑沉积区、经叠加改造的残留泥砂质沉积区、生物碎屑沉积区以及高能环境下的石英砂质沉积区。结果表明了稳健统计方法相对于传统统计方法的优越性,以及采用稳健主分量的Q载荷进行聚类分析相对于用原始变量进行聚类分析的优越性。  相似文献   

青海湖全新世植被演变及气候变迁：QH85—14C孔孢粉数值分析   总被引：20，自引：3，他引：20  

孔昭宸  山发寿 《海洋地质与第四纪地质》1990,10(3):79-90

本文应用青海湖QH85-14C孔取得的具有~(14)C测年数据所支持的原始孢粉资料,进行数值分析(有序聚类、主成份分析、滑动平均和回归分析)。从而对青海湖区11000年以来的植被和气候变化进一步讨论。  相似文献   

烟单14号玉米产量与土壤养分关系的研究     

李淑霞  冯瑞龙  赵继业  刘绍棣  程绍义 《中国海洋大学学报(自然科学版)》1988,(Z2)

根据大量田间试验和调查资料分析,作者提出烟单14号玉米生长过程中,小喇叭口期土壤中全氮、大喇叭口期土壤中速效磷的含量与产量相关密切。并据此建立了产量及构成三因素与土壤养分间的最优相关模型。  相似文献   

The influence of hydrography on the distribution of phytoplankton in the southern Taiwan Strait     

R. Huang 《Estuarine, Coastal and Shelf Science》1988,26(6)

During the period August 1985 to May 1986, phytoplankton in the southern Taiwan Strait was collected and studied for distributional variability in relation to hydrography. The results indicated that maximum standing crops of phytoplankton occurred in October and May due to the outgrowth of certain species of diatoms and blue-green algae. The majority of phytoplankton appeared in the water in the top 25 m and occurred in distinct clusters under the influence of water movement. Multivariate analysis indicated that hydrographic parameters, which accounted for the variability of phytoplankton distribution, varied seasonally. Vertical, spatial and temporal variabilities were also apparent. The close relationship between hydrography and algal distribution justifies the use of variations in the phytoplankton population as a useful tracer of water movement.  相似文献   

人工鱼礁工程的风险评估   总被引：1，自引：0，他引：1  

刘德辅  刘伟伟  庞亮 《中国海洋大学学报(自然科学版)》2007,37(2):317-322

对台风暴潮影响下的嵊泗海域人工鱼礁工程做了风险评估,考虑了台风暴潮中出现的大浪和风暴潮减水对鱼礁联合作用的危害。风险评估分为危险灾害识别、失效概率计算、失效后果评估、风险准则评定和风险管理决策几个主要的步骤。在失效概率的计算中采用基于应用设计点的重点抽样法随机模拟的技术,这一随机模拟技术可以广泛的应用与海洋工程结构的风险评估当中。  相似文献   

Assessing the relative effects of fishing on the New Zealand marine environment through risk analysis   总被引：1，自引：0，他引：1  

Campbell  Marnie L.; Gallagher  Charmaine 《ICES Journal of Marine Science》2007,64(2):256-270

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