引潮位展开的不同规格化形式及其转换

在引潮位展开过程中,为使大地系数的数值在不同阶次中保持相对稳定,对其进行规格化处理。从引潮位的基本理论公式出发,在分析缔合勒让德函数及其完全规格化的基础上,给出了引潮位展开中3类不同规格化(Doodson规格化、Cartwright & Tayler规格化、Hartmann & Wenzel规格化)公式的具体形式,得到3者之间的转换关系与转换系数。同时给出Doodson规格化中2~6阶规格化因子的具体数值,指出并改正Doodson、Roosbeek文献和IERS 2003、2010规范中的3处错误。     

测井曲线重构和频谱分析技术在塔里木盆地塔河油田卡拉沙依组储层预测中的应用

由于受不同地质情况的影响,常规测井曲线不能很好地解决特殊地质问题。针对塔河油田三区石炭系卡拉沙依组的储层地质特征,利用频谱分析技术对伽马、中子测井曲线进行处理。与常规测井曲线比较,地层的旋回特征在频谱分析曲线上更加明显。根据相同地层具有相似旋回性的原理,利用伽马、中子频谱分析曲线进行地层横向对比,使研究区卡拉沙依组砂泥段的砂组划分、对比达到了协调和统一;以声波曲线为本体,结合反映岩性的测井曲线(伽马、中子、自然电位等曲线),应用曲线重构技术构建储层特征曲线,为测井约束反演提供地质依据,使反演结果更接近于地质实际情况。利用反演资料进行储层预测的结果与测井解释有利储层段进行比较,吻合率和较吻合率分别为71.6%、11.3%。     

The Influence of the “Mixed Pixel” Problem on the Detection of Analogous Forest Communities Between Presettlement and Present in Western New York∗

We conducted a land change analysis to determine if the forest communities of presettlement and present contain areas that are analogous in composition, using surveys of the Holland Land Company (1797–1799) and U.S. Forest Service (1991–1993) from western New York. Gridded forest-type maps are produced from each survey using two models: a uniform model that assumes each data grid cell is occupied by a single forest type, and a mixture model in which grid cells are assumed to be occupied by multiple forest types in different proportions. The mixture model consistently detects a larger area of analogous communities in the two time periods at both global and local scales.     

汤原断陷始新统新安村组层序格架内多参数井约束岩性预测

汤原断陷构造岩性复杂,岩性分选是本区储层预测的关键。采用测井-地震多参数属性提取对密度曲线进行重构,消除井壁垮塌、裂缝等因素的影响。利用层序格架内多参数井约束反演方法,将层序格架研究与储层反演相结合,对汤原断陷新安村组SX1R单元进行岩性预测,预测成果与实际钻井资料吻合较好,符合程度达到87.63%。通过层序地层格架的井约束反演得出高分辨率反演数据体,刻划出目的层砂地比与砂岩的空间分布,揭示岩性展布规律:砂体厚度中心主要分布于控盆断裂一侧的深凹陷带,砂岩主要分布于西部斜坡、东部边缘和中央隆起带。     

地震反演技术在煤田勘探中的应用探讨

煤炭企业对地质安全保障的期望越来越高,特别是对查清煤层赋存形态、构造、煤层厚度、煤层顶底板条件、岩浆岩侵蚀范围等方面的要求已远超规范。以岩心、测井为约束条件的波阻抗反演,可有效提高目标地质体的预测精度。Jason反演所导出的结果是一宽频带的反射系数序列和宽频带的波阻抗数据,同时加入了低频分量,使反演结果能正确地反映地层变化规律。实例表明,在波阻抗剖面上,不仅可以预测出煤层厚度的变化趋势,而且可以反映煤层夹矸及围岩的变化规律及煤层受岩浆岩侵蚀的范围。     

最小体积约束的线性光谱解混算法

提出了最小体积单体约束的线性光谱解混算法。该算法不需要假设数据中存在纯像元,采用二次规划方法计算降维后的端元矩阵,利用最小二乘方法实现丰度估计和端元提取。实验结果表明,此算法解混的结果整体上优于MVC-NMF算法。     

GDZ-300L型履带式全液压多功能钻机的设计

主要介绍了GDZ-300L型履带式全液压多功能钻机总体结构设计、动力机的确定、液压系统设计、机械传动系统设计、主要技术参数等内容。样机试制和野外生产试验结果表明：该钻机结构紧凑、质量轻、钻进能力强、可靠性高。     

Palaeomagnetism of the loess/palaeosol sequence in Viatovo (NE Bulgaria) in the Danube basin

The results of a palaeomagnetic investigation of a 27 m thick loess/palaeosol sequence in Viatovo (NE Bulgaria) are presented in this paper. The sequence consists of topsoil S₀, seven loess horizons (L₁–L₇) and six interbedded palaeosols (S₁–S₆) overlying a red clay (terra rossa) complex. Magnetic viscosity experiments, IRM acquisition, AMS analysis and NRM stepwise alternating and thermal demagnetisation experiments of pilot samples were implemented for precise determination of the characteristic remanence and construction of a reliable magnetostratigraphical scheme. Analysis of IRM acquisition curves using the expectation – maximization algorithm of Heslop et al. [Heslop, D., Dekkers, M., Kruiver, P., van Oorschot, H., 2002. Analysis of isothermal remanent magnetization acquisition curves using the expectation – maximization algorithm. Geophys. J. Int., 148, 58–64] suggests that the best fitting is obtained by three coercivity components. Component 1 corresponds to SD maghemite/magnetite, while component 2 is probably related to the presence of oxidised detrital magnetites. The third component shows varying coercivities depending on the degree of pedogenic alteration of the samples and probably reflects the presence of detrital magnetite grains oxidised at different degree.

The relevance of the Viatovo section as a key representative sequence for the loess cover in the Danube basin is confirmed by the presence of geomagnetic polarity changes in the lower part of the sequence. The youngest one recorded in the seventh loess unit L₇ can be identified as corresponding to the Matuyama/Brunhes palaeomagnetic polarity transition. Two normal magnetozones were found in the red clay complex, probably corresponding to the Jaramillo and Olduvai subchronozones of the Matuyama chron.     

基于波场外推压制水层多次波

重点讨论了基于克希霍夫积分的波场外推方法预测水层多次波的方法原理及具体的数值实现.自适应减法是波动方程方法压制多次波的另一个重要方面,考虑到Monk提出的带约束的互均衡化算法在复杂模型情况下压制效果不是很理想,本文对其算法进行了改进,提出了基于矩形窗和海宁(hanning)窗的分段匹配算法,模型算例的处理结果表明,改进后的算法具有一定的优越性.