小口径割管器的设计与应用

某盐井施工时,在245．00—270．00m孔段有25m钻具被水泥固结,进行透孔作业时,扫至孔深250．60m时,扫孔用岩心管被扫落的钻杆接头碎块卡住拧断,透孔时发现孔内遗留3．2m断岩心管、钻头等物。根据钻孔结构与遗留钻具的特点．自行设计一种主要由活塞柱、割刀片和复位弹簧组成的小口径割管器,将水泥固结钻具割断,并将钻具和多种残留管材打捞出孔。从割断后打捞上来的钻杆分析,钻杆切割面光滑、平整,钻杆被完全切透,说明此种割管器设计合理,各部件动作有效。     

国外天然气水合物岩心处理分析技术综述

分析了国外天然气水合物岩心研究现状,并从钻井液和实时监控两方面讨论分析了钻进和取心中存在的安全问题.对于岩心取样和保存,主要探讨了压力和温度的保持与现场取心和取样的方法,然后结合取心上存在的主要差异、关键岩心性质以及MALLIK和ODP Joides决心号钻探船上岩心的实验室研究,探讨了天然气水合物的岩心分析.最后针对国内研究现状提出了几点建议.     

Wavelet triangulated irregular networks

GIS applications have recently begun to emerge on the Internet. The management of three-dimensional geographic datasets in this distributed environment poses a particularly challenging problem, which highlights the need for a good data representation. This paper presents a new multiresolution data representation: the Wavelet Triangulated Irregular Network (WTIN). Compared to the traditional cell-based Digital Elevation Model (DEM) format and the Triangulated Irregular Network (TIN) format, it is more compact and suitable for scalable distributed GIS services. This format is based on the second-generation wavelet theory and is specially designed for geographical height field data. The modified Butterfly scheme is used for constructing the wavelet transform. For every point in the geographic surface, only a single wavelet coefficient is used, which makes the final data representation very efficient and easy to compress. Because the transform used in the data representation is a linear filter operation, the computational efficiency is better than other multiresolution data formats for terrain surfaces. Results from numerical experiments on real data are given to demonstrate that the proposed data representation can be efficiently implemented. The results show that the proposed WTIN data format can provide multiresolution data sets, which achieve significant compression while preserving geographical features. The quality is found to be quite acceptable for geographical terrain representation.     

页岩气藏评价中的岩石物理方法

岩石物理在页岩气勘探开发中非常重要,而文献中至今缺少足够的重视.本文分别从页岩气藏的地质特征、评价参数、岩心分析工作流程及测井工作流程等4个方面探讨页岩气储层的固有特征及岩石物理所起的关键作用.从生烃潜力、储存性能、流动特性和力学性质讨论相关评价参数的岩石物理方法,重点讨论吸附气含量的计算、力学性质及基质渗透率的测量.在页岩气储层测井评价方面,重点探讨有机质含量的测井评价方法、页岩气层孔隙度的评价方法、随钻测井用于水平井的地质导向、及测井评价在制定压裂方案中的应用.     

混凝土核心筒的水平双向循环加载试验研究

为了研究地震多维性对于混凝土核心筒抗震性能的影响,对大尺寸混凝土核心筒试件进行了水平双向加载下的拟静力试验.重点研究在双向加载下,核心筒的破坏形态与机理、承载能力、变形性能、刚度退化等方面的问题.结果表明,由于水平双向加载下简体一个方向的损伤影响到另一个方向的性能,因而对混凝土核心筒的抗震能力造成不利影响.因此,在实际工程中应合理地考虑这种影响,这对于确保混凝土核心筒的抗震安全具有重要意义.     

A study on the seismic performance of steel‐reinforced concrete frame‐concrete core wall high‐rise mixed structure by large‐scale shaking table tests and numerical simulations

This paper reports a study for the seismic performance of one large‐scaled (1/15) model of 30‐story steel‐reinforced concrete frame‐concrete core wall mixed structure. The study was implemented by both shaking table tests, in which the similarity ratio for lateral and gravitational accelerations was kept to 1:1, and numerical nonlinear dynamic analysis. The test observations presented herein include story displacement, interstory drift, natural vibration periods, and final failure mode. The numerical analysis was performed to simulate the shaking table test procedure, and the numerically obtained responses were verified by the test results. On the basis of the numerical results, the progressions of structural stiffness, base shear, and overturning moment were investigated, and the distributions of base shear and overturning moment between frame and core wall were also discussed. The test demonstrates the seismic performance of the steel‐reinforced concrete frame‐core wall mixed structure and reveals the potential overturning failure mode for high rise structures. The nonlinear analysis results indicate that the peripheral frames could take more shear forces after core wall damaged under severe earthquakes. Copyright © 2013 John Wiley & Sons, Ltd.     

The instability of barotropic circular vortices

Abstract

The linear, normal mode instability of barotropic circular vortices with zero circulation is examined in the f-plane quasigeostrophic equations. Equivalents of Rayleigh's and Fjortoft's criteria and the semicircle theorem for parallel shear flow are given, and the energy equation shows the instability to be barotropic. A new result is that the fastest growing perturbation is often an internal instability, having a finite vertical scale, but may also be an external instability, having no vertical structure. For parallel shear flow the fastest growing perturbation is always an external instability; this is Squire's theorem. Whether the fastest growing perturbation is internal or external depends upon the profile: for mean flow streamfunction profiles which monotonically decrease with radius, the instability is internal for less steep profiles with a broad velocity extremum and external for steep profiles with a narrow velocity extremum. Finite amplitude, numerical model calculations show that this linear instability analysis is not valid very far into the finite amplitude range, and that a barotropic vortex, whose fastest growing perturbation is internal, is vertically fragmented by the instability.     

Resistive wave breaking in the Earth's outer core

The equations for an electrically conducting fluid in cylindrical coordinates are linearized assuming that the inertial terms in the momentum equation can be ignored (small Rossby number), and that the ratio of the Elsasser number and magnetic Reynolds number is one. After these assumptions, the governing equations are linearized about an ambient solution which vanishes at the the equator. Upon assuming large Elsasser and magnetic Reynolds number, the solutions to the linearized equations are approximated by wave trains having very short wave length (relative to the core radius) but which vary slowly (on a scale of the core radius). The period of the waves is much longer than a day but much shorter than the period of the slow hydromagnetic oscillations. These waves are found to be trapped in a region about the equator and away from the axis of rotation. The waves break at a latitudinal wave region boundary, in the sense that the waves become exponentially large in a boundary layer, having as an exponent some positive power of the large azimuthal wave number. This behavior is amplified as the Elsasser number becomes smaller while still remaining relatively large. Waves in more Earth-like parameter regimes are discussed briefly.     

浅谈提高地质岩心钻探质量指标的若干问题

结合新发布的地质岩心钻探规程中的钻探工程质量要求,通过多年来的生产实践,就如何提高钻探质量指标问题进行探讨,并浅谈几点认识.