杭锦旗区块二叠系气层产能影响因素分析

杭锦旗区块上古生界二叠系发育了多套近源陆相碎屑岩沉积,自下而上存在着多套含气层砂体。储层具有中低孔低渗且纵横向非均质性较强等特征,致使气层需压裂改造后才具有一定产能。综合运用薄片、X衍射、压汞等实验资料及钻井测试成果,对气层的伤害、产能与探测半径和产能系数之间关系等进行分析研究,认为本区气层易受外来侵入流体污染,压裂规模和解堵有效程度将制约着气层产能。因此,若要有效改造气层和提高天然气产能,必须针对本区二叠系气层特有的特征,研究和采用合理的钻井技术、压裂工艺保护气层和加大压裂规模、扩大其渗流面等气层改造方法。     

Convergence of Liapunov series for Huygens–Roche Figures

According to the classical theory of equilibrium figures, surfaces of equal density, potential and pressure concur (let us call them isobars). Isobars can be represented by means of Liapunov power series in small parameter q, up to the first approximation coinciding with the centrifugal to gravitational force ratio at the equator. Liapunov has proved the existence of the universal convergence domain: the above mentioned series converge for all bodies (satisfying a natural condition that the density ρ decreases from the center to the surface) if |q| < q*. Using Liapunov’s algorithm and symbolic manipulation tools, we have found q*= 0.000370916. Evidently, the convergence radius q* may be much greater in common situations. To comfirm it it is reasonable to consider two limiting and one or two intermediate cases for the density behaviour: ρ is a constant, the Dirac’s δ-function, linear function of the distance from the center, etc. And indeed, in the previous paper we find a three orders of magnitude greater value for homogeneous figures. In the present paper we find that in the opposite case of Huygens-Roche figures (a point-mass surrounded by a weightless atmosphere) the convergence radius is unexpectedly large and coincides with the well-known biggest possible value q*= 0.541115598 for such a class of figures. To ascertain it we ought to use numerical calculations, so our main result is demonstrated by means of a computer assisted proof. This revised version was published online in July 2006 with corrections to the Cover Date.     

磁感应阻力对导体卫星在圆形轨道上的摄动影响

用功能转换原理和摄动理论的两种方法重点研究了导体卫星在地球磁场和有电导率介质空间飞行时磁感应阻力对圆形轨道半径的摄动影响。理论研究表明：导体卫星在圆形轨道上受磁感应阻力后轨道半径有随时间变化的长期摄动效应外还有周期性变化。此外，文中还讨论了磁感应阻力对圆形轨道的其它要素的摄动影响概况。     

Chondrule size and related physical properties: A compilation and evaluation of current data across all meteorite groups

The examination of the physical properties of chondrules has generally received less emphasis than other properties of meteorites such as their mineralogy, petrology, and chemical and isotopic compositions. Among the various physical properties of chondrules, chondrule size is especially important for the classification of chondrites into chemical groups, since each chemical group possesses a distinct size-frequency distribution of chondrules. Knowledge of the physical properties of chondrules is also vital for the development of astrophysical models for chondrule formation, and for understanding how to utilize asteroidal resources in space exploration. To examine our current knowledge of chondrule sizes, we have compiled and provide commentary on available chondrule dimension literature data. We include all chondrite chemical groups as well as the acapulcoite primitive achondrites, some of which contain relict chondrules. We also compile and review current literature data for other astrophysically-relevant physical properties (chondrule mass and density). Finally, we briefly examine some additional physical aspects of chondrules such as the frequencies of compound and “cratered” chondrules. A purpose of this compilation is to provide a useful resource for meteoriticists and astrophysicists alike.     

地球扁率在地质历史上的变化下限

为研究地球形状的长期变化,将地球假设为弹性椭球体,根据弹性动力学理论导出地球的扁率下限公式,扁率与地球的平均密度ρ、引力加速度g、自转角速度ω、平均半径R、弹性模量E、泊松比v相关.将新星云假说下地质历史时期半径、质量和角速度变化值代入公式计算出各地质历史时期地球扁率值,作为地球扁率变化值的下限值.地球的扁率自地球形成以来总体变化趋势是在减小.     

基于LiDAR点云的复杂钢结构模型重建

传统的基于全站仪等单点测量技术难以获取钢结构整体信息,且测量速度慢、模型重建精度低。针对此问题,本文将三维激光扫描技术应用于钢结构模型重建领域,提出了基于LiDAR点云的复杂钢结构模型重建方法。首先,基于标靶球和钢结构面信息实现多测站点云的高精度配准,并通过半径滤波算法去除噪点,以得到完整的激光点云数据;然后,对复杂钢结构单体模型进行分割,以实现各个部件的模型重建;最后,根据现场实测数据对重建的三维模型进行精度评估。试验结果表明,基于该方法得到的模型精度较高,与实际尺寸差值均小于1 cm,为复杂钢结构的三维模型重建提供了有效解决方案。     

大坡度并小半径曲线盾构连续穿越建筑群沉降施工控制

以天津地铁三号线水上北路站一吴家窑站盾构区间左线施工为背景,针对盾构施工区间遇到的大坡度并小半径曲线且连续穿越建（构）筑群盾构施工的综合难题,利用施工过程中积累的各种数据,采用归纳总结分析和数理统计的方法,分析了地面建筑物沉降与地质、推力、注浆、纠偏等参数的关系,得出了影响建筑物沉降的因素主要为曲线和纠偏时的超挖、推进速度、注浆参数及注浆方法,总结了控制地面建筑物沉降的管理与技术措施。     

K0固结饱和土柱孔扩张问题弹塑性分析

采用K0固结各向异性土体本构模型,将柱孔扩张后周围土体分为弹性区和塑性区,根据柱孔扩张理论和边界条件,推导出K0固结状态下饱和天然土体柱孔扩张问题弹塑性区的应力、塑性区半径以及超孔隙水压力的理论解答。同时,通过算例与修正剑桥模型解答进行对比分析,结果表明,土的不同初始固结状态对柱孔扩张后孔周围的应力和超孔隙水压力产生很大影响,采用考虑K0固结诱发各向异性土体本构模型所得到的应力和超孔隙水压力解答大于修正剑桥模型的解答,但塑性区影响半径却明显小于后者。     

QuikSCAT风场在台风风暴潮计算中的应用

业务化风暴潮计算中多采用模型风场的算法来给出风暴潮强迫场。最大风速半径是模型风场最难确定的参数之一。利用QuikSCAT卫星风场数据拟合台风最大风速半径是确定该参数的有效方法。将拟合得到的最大风速半径代入模型风场计算风暴潮的驱动场,模拟的沿岸风暴增水与实况更为接近。     

超短半径径向水平井抽采煤层气渗流规律的数值模拟

为得到超短半径径向水平井开采煤层气过程中的气体渗流规律以及进行产量预测,在基本假设条件下,建立了径向水平井开采煤层气的固流耦合渗流数学模型;在一定的边界条件及初始条件下,利用Matlab软件进行编程计算后,得到直井和不同数目分支径向水平井开采煤层气1000天后的压力场、速度场和气产量变化规律。数值模拟结果表明,在一定的生产区域和开采时间,随着径向水平井分支数目的增加,煤储层压力下降范围更广,气体流速场干扰加强,压力漏斗降大面积扩展,煤层气有效供气区及解吸面积大幅增长,煤层气解吸能力及稳产能力加强,煤层气产量大幅度增加;同时,气产量增幅随着井筒分支数目的增加而下降,分支井数目理论上应存在一个最优值。模拟结果显示了超短半径径向水平井技术开采煤层气的有效卸压作用,对煤层气工业增产技术的选择和钻孔方案的布置具有重要的理论指导意义。