三种混合泥质砂岩有效介质通用电阻率模型比较

复杂泥质砂岩油气层的识别与评价一直是测井解释领域亟待解决的难点和热点问题,因此,针对复杂泥质砂岩油气层的特点,有必要研究能够描述这类储层导电规律的新导电理论。针对用于复杂泥质砂岩油气层解释的3种混合泥质砂岩有效介质电阻率模型,从理论和实验角度,进行了全面系统的比较。通过对3种有效介质通用电阻率模型建模理论基础的分析,可知混合泥质砂岩有效介质非对称模型基于HB方程和并联导电理论,对称模型基于对称导电理论和并联导电理论,而孔隙结合模型基于混合介质电导率积分方程;对称电阻率模型可用于多连续项存在的地层,而非对称电阻率模型和孔隙结合电阻率模型只允许水为连续项。对骨架不导电的纯砂岩进行模型化简,可知非对称电阻率模型和孔隙结合电阻率模型可以简化成阿尔奇公式,而对称电阻率模型能化简成类似阿尔奇公式。通过1组混合泥质砂岩人造岩样和2组分散泥质砂岩岩样以及1组骨架导电人造岩样的实验数据,验证3种有效介质通用电阻率模型均适用于混合泥质砂岩地层解释,且精度相近。     

裘布依公式在实际应用中的缺陷分析

主要通过对裘布依公式中：1）实际流量（Q）-降深（s）曲线与理论的差异,2）实际井径对流量的影响与理论的差异,3）井中最大流量,4）影响半径等问题的分析,指出裘布依公式的缺陷,并分别提出了一定的解决方案。同时还结合土力学的相关知识,从“达西定律的适用范围”,“渗透系数的不唯一性”,“地基沉降导致含水层变形”三个方面分析了公式的不足之处,更全面地对问题进行了剖析。     

深层岩体松动爆破中不耦合装药效应的探讨

基于冲击波在交界面两侧压力和速度必须各自相等的连续性条件,求解爆轰产物中适用的反射波方程和介质中适用的冲击波方程,得到药包周围介质中冲击波的初始参数.通过波的传播机理,把集中药包应力波随距离的衰减公式扩展到延长药包,并计算耦合与不耦合装药爆破时距爆心相同距离处岩石中冲击波的参数.由计算结果可知:(1)耦合装药爆破时形成的冲击波压力超过岩石抗压强度极限几十倍以上,药包周围岩石形成粉碎区;(2)与耦合装药爆破相比,不耦合装药爆破可以降低孔壁处岩石中冲击波初始压力,但可以增加孔壁后岩石中的冲击波压力.合理的不耦合系数,可使岩石不形成粉碎区,大幅度减少能量耗散;(3)水一般认为是非线性弹性介质,因此水介质成为炸药爆轰产物与岩石间的弹性缓冲层,增加了能量传递,延长了冲击波作用时间,加大了爆炸的作用范围.     

重力数据误差对大地水准面模型建立的影响

基于Stokes理论建立的大地水准面模型,其精度受重力数据误差,即重力数据分辨率、精度以及积分范围的影响。针对这一问题,通过重力场谱特征分析,给出不同地形区域重力数据分辨率以及积分半径造成的大地水准面高频截断误差的量级大小,计算平均重力异常误差对大地水准面建模精度的影响。研究成果对不同地形区域cm级大地水准面模型的建立具有理论与指导意义。     

Roughness coefficients and velocity estimation in well-inundated sheet and rilled overland flow without strongly eroding bed forms

Even with the flow of water over a soil surface in which roughness elements are well inundated, and in less erosive situations where erosional bed forms are not pronounced, the magnitude of resistance coefficients in equations such as those of Darcy–Weisbach, Chezy or Manning vary with flow velocity (at least). Using both original laboratory and field data, and data from the literature, the paper examines this question of the apparent variation of resistance coefficients in relation to flow velocity, even in the absence of interaction between hydraulics and resulting erosional bed forms. Resistance equations are first assessed as to their ability to describe overland flow velocity when tested against these data sources. The result is that Manning's equation received stronger support than the Darcy–Weisbach or Chezy equations, though all equations were useful. The second question addressed is how best to estimate velocity of overland flow from measurements of slope and unit discharge, recognizing that the apparent flow velocity variation in resistance coefficients is probably a result of shortcomings in all of the listed resistance equations. A new methodology is illustrated which gives good agreement between estimated and measured flow velocity for both well-inundated sheet and rill flow. Comments are given on the predictive use of this methodology. Copyright © 1999 John Wiley & Sons, Ltd.     

Control law for variable damping device defined by a non-linear differential equation

This paper proposes a non-linear control law for a variable damping device (VDD) aimed at reducing structural seismic responses. The VDD is attached to the structure by an auxiliary spring element composing a non-linear Maxwell element. The VDD's damping coefficient is adjusted to control the reactive internal force in the non-linear Maxwell element. A large controlled force is thus produced with little external power required to adjust the VDD's damping coefficient. The proposed control law defines the rate or increment of the VDD's damping coefficient at a certain moment by a differential equation or its discretized form. The controlled force vs. deformation relation plots parallelogram-like hysteretic curves, which indicates quick action and energy dissipation. Fundamental characteristics of an SDOF model with the VDD controlled by the proposed law are examined for impulse, sin and seismic excitations. The law for the SDOF model is extended to one for an MDOF model. The control effect for a 3DOF model is examined by numerical experiments. Copyright © 1999 John Wiley & Sons, Ltd.     

2002年7月15日华北地区酷热事件的诊断分析

为开展对高温酷热天气事件的研究 ,根据 2 0 0 2年 7月 15日我国华北大部分地区出现地面气温 >40℃的酷热天气 ,利用已有的各种观测资料 ,对酷热事件发生前和发生时的地面和高空天气形势进行了分析 ,并详细讨论了各物理量的时空分布情况。热力学方程各项因子的诊断分析表明 ,此次“酷热”事件是由于温度平流、温度垂直输送和非绝热加热 3个因子共同作用的结果。     

考虑流固耦合时的海洋平台结构非线性动力分析

采用非线性的Morison方程,建立了考虑流固耦合时的海洋平台非线性动力方程及其时程分析方法.以一固定式导管架平台为算例,计算了考虑流固耦合时的海洋平台浪致振动响应,比较了考虑流固耦合和不考虑流固耦合时海洋平台动力响应的差异.算例表明：在较大的波浪条件下,不考虑流固耦合时的计算结果明显小于考虑流固耦合时的计算结果,因此,偏于不安全.分析认为,在极端海况条件下,考虑流固耦合的分析方法更符合实际情况.