塔河油田盐膏层承压堵漏技术

塔河油田地质情况极为复杂,在塔河南区块经常性钻遇厚度不等的盐膏层.由于盐膏层在高温高压条件下呈塑性蠕变状态,极易造成井下事故,造成不可估量的损失.为了克服盐膏层塑性蠕变,需要提高钻井液密度.而上覆三叠系地层抗破能力差,极易发生漏失:为提高上覆地层的抗破能力,最为有效的办法就是承压堵漏.本文从方案优选,试验配伍,实际操作...     

横观各向同性地基的三维Biot固结有限层求解

将有限层法应用于求解Biot固结问题 ,推导了横观各向同性地基的三维Biot固结问题的有限层求解格式 ,并编制了相应的计算程序对算例进行计算分析 ,通过计算结果与Biot固结理论解的对比证实了方法的正确性     

黄岩汇煤矿开采对地下水的影响研究

介绍了黄岩汇煤矿所在地区的水文地质情况,应用Visual MODFLOW软件,通过对计算域进行剖分,确定二类流边界,采用迭代逼近法模拟预测了黄岩汇煤矿15号煤层开采对上覆含水层的影响。结果表明,煤矿开采59.8 a后,漏斗中心的水位降深约为60 m,影响面积约为54.4 km2。     

三维横观各向同性土体开挖问题有限层求解

首先探讨了有限层法求解开挖问题的难点:开挖等效荷载的有限层表达和开挖后刚度矩阵的有限层计算,并在此基础上建立了三维横观各向同性土体开挖问题的有限层求解格式,并编制了相应的计算程序。计算结果同实测值一致性证实了方法的正确性和有效性。     

油气层保护用淀粉微球承压能力评价研究

通过对自制淀粉微球粒径分布、承压能力和岩心端面微观形貌分析可得,微球的D10、D50、D97分别为3.00、18.68和92.05μm,粒径的区间百分含量呈偏差正态分布。淀粉微球在中高渗岩心中承压能力最高,最大可达16.3 MPa,说明岩心在(50～70)×10~(-3)μm~2渗透率下的孔喉尺寸与淀粉微球的粒径更加匹配。而在低渗岩心中,淀粉微球承压能力不佳。从岩心端面电镜图发现中高渗岩心在入口端和出口端均可见微球状物质,说明有部分微球颗粒已嵌入岩心孔喉,并且少量微球颗粒在岩心内部发生运移。由此可见,此粒径分布的淀粉微球在渗透率大于50×10~(-3)μm~2的中高渗地层将会发挥较大"屏蔽暂堵"作用。     

察尔汗盐湖S4层盐岩卤水含水层的渗透性特征

察尔汗盐湖是柴达木盆地的最大盐湖,其开采利用的主要对象为S4盐岩卤水含水层,作为可溶盐(岩)含水层,其矿物组合及沉积特点,决定该含水层基本特征及主要水文地质参数将随晶间卤水的开采规模、卤水渗流场及卤水化学场的变化而呈现易变性,从而又进一步影响渗流场和水化学场的变化,以致影响到卤水矿有效合理的开采。了解S4层含水层基本特征,摸清晶间卤水运动规律,正确确定其水文地质参数,无论从科学研究还是生产开采,均有着重要的理论和现实意义。     

地层承压能力的影响因素分析

对于低压易漏井,或多套压系统下的地层,常常因地层承压能力差而发生井漏事故。本文详细总结了地层承压能力的影响因素,并对其进行了深入研究和探讨,对提高地层承压能力的室内试验及现场研究提供了重要的参考。     

用有限体积法研究二维矩形散射介质辐射传递

用直角坐标系下有限体积法研究了二维矩形介质内辐射传递,散射相函数采用Legendre多项式展开.与其他文献的计算结果比较证明了本文有限体积法模型是可靠的.研究表明,相函数及反照率等对温度分布有影响.比较了线性各向异性散射与各向同性散射矩形介质内的温度场,对于不同的误差要求对应存在一个衰减系数及反照率取值区域,在该区域内选取物性参数则可以将线性各向异性散射简化处理为各向同性散射,从而方便了计算.     

基于焊接仿真的承压管道开孔设计分析

提出并分析了一种对电厂承压管道中开孔(依据工艺要求确定孔的大小)采用支管焊接(BOSS头型式)回堵的操作形式的可行性,经结构强度分析、焊接残余应力和变形快速仿真分析可知:该操作形式能最大限度地降低其对主管道应力和变形的影响.     

承压金属元件超声波探伤中声程修正的条件分析

对承压元件进行超声波探伤中,常常会遇到声程修正的问题。根据JB/T4730—2005《承压设备无损检测》,结合检测人员习惯得到简体直径D和壁厚t的直观数据的情况,对免于声程修正的简体最大壁厚进行了分析。结果表明,在进行常规设备超声波检测时就不必时常担心曲面的声程修正,对较高压力或筒径较小的设备时,才考虑曲面修正。     

受限微细通道内的流动沸腾流型转化准则

理论分析了微细尺度条件下通道尺寸对气泡运动特性的影响,指出当通道尺寸小于气泡脱离直径时一种特殊流型"受限泡状流"的产生及其特性。对受限通道内流动沸腾过程中的流型转变准则进行了推导,绘制了相应的流型图,并进行了实验验证。研究表明,微细通道内沸腾流动气液两相流流型转变比绝热工况下有明显的推迟;而在流动沸腾工况、相同热通量和质量流速条件下,随着微细通道尺寸的减小,流型转化会在一定程度上提前产生。     

Numerical calculation of the limiting current for a cylindrical thin layer flow cell

A cylindrical thin layer flow cell for the investigation of electrochemical reactions is described. Due to the geometry of the cell, known approaches to a quantitative interpretation of the measurements based on high flow rate asymptotics fail. Instead, a numerical method is introduced which models coupled fluid flow and reactant transport. Due to the use of a pointwise divergence-free finite element method, coupled to a finite volume method, the obtained approximate reactant distribution is guaranteed to remain in physically relevant bounds. The method is used to interpret limiting current measurements in the flow cell. The comparison to the measured values shows that a quantitative interpretation of the limiting current measurements depends on the ability to obtain sufficiently exact information about cell geometry, diffusion coefficient and inlet concentration. At the same time, for higher flow rates, the scaling of the limiting current with the flow rate seems to be well described by the Leveque asymptotic law for channel type cells.     

单螺杆挤出机中三维流动有限体积数值模拟

Based on the vortex-velocity method,the dimensionless control equations of three-dimensional flow in single screw extruder were developed,and a new simulation method for the flow of non-Newtonian fluids was presented.A staggered grid arrangement was used,in which the dependent variables were located at different mesh points in the computational domain.The discretization scheme was second-order accurate,resulting from the use of central differencing.The simulation concerned the incompressible fluid obeying power law and the application of the finite volume method to the geometrical configuration of channel with aspect ratio up to 13.The distributions of velocities and stresses were investigated for different longitudinal pressure gradients.It was found that the distributions of velocities and stresses agreed well with the result of the two-dimensional approximation over 84% width scope owing to the large aspect ratio of the cross-section of the channel.The output decreased linearly with the increase of the longitudinal pressure gradients as observed in dimensionless forms.In addition,the center of the recirculating region in the channel cross-section drifted upward with the increase of longitudinal pressure gradients,which had positive influence on mixing performance.     

大开间约束砖砌体结构的抗震性能与设计方法

提出对大开间砖砌体结构采取在砖砌体中设置钢筋混凝土墙中柱和水平条带的加强措施。通过大比例模型试验 ,探讨其抗震性能 ;采用非线性有限元法对约束砌体横墙进行全过程分析 ,采用弹塑性时程分析法对原型结构进行地震反应分析 ;在此基础上提出了相应的设计建议和构造措施。试验与理论分析结果表明 ,在 7度区采用大开间约束砖砌体结构建造 7层住宅 ,可满足抗震设防要求。     

Multi-scale finite element modelling of laminar steady flow through highly permeable porous media

The Brinkman equation is used to model the isothermal flow of Newtonian fluids in a highly permeable porous medium between two parallel plates. Due to the multi-scale nature of flow regimes represented by the Brinkman equation, the standard Galerkin method requires excessive mesh refinement to achieve stable and accurate results. To avoid this, a residual free method is used to derive appropriate bubble functions for inclusion in the finite element discretisations. It is shown that by using bubble enriched shape functions the standard Galerkin method can yield accurate and stable solutions for multi-scale problems. In this paper the performances of the third and fifth order bubble functions used in conjunction with bilinear Lagrangian elements to solve the Brinkman equation via a penalty finite element scheme, are reported.     

运动单帧图像法湍流边界层相干结构的实验测量

在研究单帧单曝光图像法（SFSE）流场测量的基础上,提出了测量湍流边界层相干结构的运动单帧长曝光图像法（MSFLE）,该方法是具有拉格朗日性质的测量方法,测量时相机以被拍摄相干结构的迁移速度基本相同的速度移动,同时采用长曝光的方法记录粒子的运动轨迹。应用该方法,得到了充分发展湍流边界层流向-展向平面内相干结构的直观图像,清晰地展示了相干结构随时间与空间的发展演变过程,并对其中的运动特征进行了分析研究。实验结果表明,高低速条带之间的相互作用可以导致发夹涡的位移、合并和耗散,鞍点及附近强剪切层的存在是相干结构发展演化的关键。     

Comparison of finite volume and lattice Boltzmann methods for multicomponent flow simulations

In pseudopotential lattice Boltzmann (LB) models for simulating multicomponent flows, interaction forces between the components of a mixture lead to phase separation and interfacial tension. At the macroscopic scale, such LB models solve an advection-diffusion equation for each component and the Navier-Stokes equations for the fluid mixture. In this paper, the computational efficiency of the LB method is compared with a finite volume (FV) solver for the same macroscopic-scale equations for a binary system in a two dimensional domain. The FV implementation replicates the phase separation of the LB model. Differences in the interfacial tension are due to truncation of the Taylor series expansion of the LB interaction force in the FV version. While the computations required to update the domain for each timestep can be completed faster with the FV approach, a smaller timestep is required to achieve stability, which negates the improvement in processing speed. The FV implementation, however, allows independent variation of model parameters, which is not possible in LB. For example, the viscosity can be changed without affecting interfacial tension or the extent of phase separation. Furthermore, it is possible to obtain low interfacial tensions without suppressing phase separation with the FV formulation. The significance of changing the diffusion rate of components on the deformation of a droplet in shear is also demonstrated. For three-dimensional simulations, the finite volume approach is expected to be faster than LB and would benefit from the demonstrated flexibility in specifying model parameters.     

几种有限元分析方法在机头流道分析中的应用研究

研究了 3种有限元分析方法———流函数法、侧壁因子修正法和全高三棱柱单元法在挤出机平板机头流道分析中的应用情况。结果表明 ,流函数法只适合分析流道高度不变化或变化极小的情况 ;侧壁因子修正法误差较小 ;全高三棱柱单元法比较精确 ,但分析方法复杂     

Numerical simulation of reacting plane mixing layer by particle method

This paper proposes a two-dimensional particle method for a plane mixing layer with a single-step and irreversible chemical reaction. The vorticity and concentration fields are discretized into the vortex and concentration elements, respectively, and the behavior of the elements is calculated with the Lagrangian method. The reaction is estimated through the calculation for the time rate of change in the strength for concentration element. The method is applied to simulate the reactive plane mixing layer. The simulation demonstrates that the mixing and reaction phenomena caused by the large-scale eddies are successfully captured. It is also confirmed that the effects of the Damköhler number and stoichiometric ratio on the reaction are favorably analyzed by the method.