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1.
水平井变质量流研究进展   总被引:15,自引:0,他引:15  
综述了水平井筒沿管壁具有流体流入的变质量流动的最新研究 进展.内容包括:考虑油藏流体流入时井筒流动压力及产量的计算,具 有不同流入时管壁摩擦系数的经验计算公式,以及流体径向流入井筒 后流动阻力损失产生的机理分析等.重点介绍了水平井筒变质量流动 阻力系数的计算,同时文中还介绍了井筒两相变质量流动损失产生的 机理和数值模拟研究进展.  相似文献   

2.
欧阳伟平  张冕  孙虎 《力学学报》2016,48(2):464-472
多段压裂水平井技术是目前开采致密气最常用的方法之一,在致密气压裂水平井试井测试中常常伴随着一定的产水量,井筒气液两相流会增加井筒流体的流动阻力,加大井筒流体流动对试井解释的影响.为了明确井筒气液两相流对致密气藏压裂水平井试井的影响,提高产水致密气压裂水平井的试井解释精度,建立了一种井筒气液两相流与地层渗流耦合的试井模型,采用数值方法对模型进行求解,获得了考虑井筒气液两相流的压裂水平井试井理论曲线、压力场分布及裂缝产量分布.研究结果表明:井筒气液两相流会增加试井理论曲线中压力和压力导数值,造成靠近入窗点的压力扩散要快于远离入窗点的压力扩散,引起靠近入窗点的裂缝产量要高于远离入窗点的裂缝产量.现场实例分析进一步说明,不考虑井筒两相流可能会对产水压裂水平井的试井解释结果产生很大误差,主要表现为水平井筒假设为无限大导流能力会使得拟合得到的表皮系数偏大,将测试点视为入窗点会使得拟合得到的原始地层压力偏小.所建立的考虑井筒两相流的压裂水平井试井模型为产水致密气井试井资料的正确解释提供了重要技术保障.  相似文献   

3.
通风阻力的计算与测定是保障煤矿安全生产必须进行的日常工作。通常认为巷道内造成风流能量损失的途径主要是沿程摩擦损失、局部阻力损失、热阻力。传热导致流体物性参数会发生大变化,产生热阻力。巷道内不断有水蒸气和瓦斯等气体掺混进入主流空气中,形成复杂的对流传质现象,同样也会影响物性参数,从而产生附加通风阻力。这是一种被人们忽视的能量损失。本文对这种能量损失形式进行了探讨,提出了传质附加阻力概念,并运用CFD模拟技术研究了不同传热、不同散湿强度下通风阻力的变化规律。结果表明:当巷道风流速度低于0.5m/s时,传质使巷道阻力增加15%以上;当风速增大到2m/s以后,传质对巷道阻力的影响减弱,使巷道阻力约增大5%左右;当传质与传热同时存在时,传质会削弱热阻力,其综合效果不是简单的代数相加,传热与传质对阻力的影响是同一数量级。文中给出了传质附加阻力拟合计算式,可用于实际巷道通风设计和日常矿井通风能力核定。  相似文献   

4.
水平井开采石油遇到的几个流体力学问题   总被引:1,自引:0,他引:1  
本文从渗流力学和流体动力学方面讨论了利用水平井技术开采石油时在油藏工程和采油工程中遇到的几个力学问题,如水平井产量的计算,水平井非稳态试井及流场分析,水平井井筒内压力降及其对产量的影响、水平井近井油藏和井筒内流体流动耦合等,半提出水平井开采机理仍存在很多基础理论需要研究解决。  相似文献   

5.
通过模型实验和数值模拟计算,研究了带有涡激振动抑制罩的圆截面柱体的水动力特性.模型实验主要测试了柱体上附加谐波型和类圆锥型涡激振动抑制罩的单摆结构在不同流速下发生涡激振动的性质;数值模拟则针对谐波型和圆锥型扰动,在雷诺数Re为10~2到10~5范围内,研究其水动力参数,如阻力、升力和涡脱落频率等,随扰动波长和波动强度的变化.模型实验结果表明,在直圆柱开始发生共振的流速下,带抑制罩的柱体的振幅显著降低,而在更高流速下则显著增大.数值模拟结果表明,谐波型和圆锥型扰动具有相似的水动力特性;且在不同Re时,阻力、升力和涡脱落频率具有相似的变化规律;随波动强度的增大,阻力一般逐渐增大,升力则在多数情况下先减小而后增大,而涡脱落频率一般逐渐减小.  相似文献   

6.
管内固-液两相流动阻力特性影响因素的敏感性分析   总被引:1,自引:0,他引:1  
在浆体管道的工程设计中,管道阻力损失是一项关键参数。在大量实验的基础上,本文根据取得的有关实验成果,对影响管内固-液两相流动阻力的4个最主要因素-管径D、颗粒比重S、浆体浓度Cv和倾角θ进行了深入探讨,并采用多因素分析法比较了它们对于固体物料管道水力输送阻力输送阻力损失的影响程度大小关系,从而为在工程设计降低管道输送阻力提供了主要调整手段。  相似文献   

7.
制备了羰基铁粉(CIP)的质量分数为70%的硅树脂基磁流变胶。用安东帕MCR-301型流变仪对其流变特性进行了测量,并对测试结果进行了Herschel-Bulkley本构模型参数识别。最后对MRG-70在该模型下磁流变减振器旁路中的泊肃叶(Poiseuille)流动展开了分析。试验及分析结果表明,在外加磁场下,Herschel-Bulkley本构模型中非牛顿指数n1。剪切应力随半径的增大而线性增大;当τ_rτ_y形成剪切流,反之则为柱塞流动。在剪切流动区域内,流速随半径增大而非线性降低,剪切速率随半径增大而非线性增大。磁感应强度越大,柱塞流区域越大,柱塞流区域内剪切速率恒为0。体积流量随磁感应强度增强而非线性减小。在0mT~500mT之间体积流量随磁感应强度变化剧烈,进一步增加磁感应强度则变化缓慢。  相似文献   

8.
为研究水平管内气液两相螺旋流的流动特性,开展了以空气和水为实验介质,含气率为10%~90%,气相折算速度为0.01~3.4m/s,液相折算速度为0.05~2.7m/s的气液两相螺旋流实验.利用高速摄影机记录并参考借鉴相关研究结果分析和划分了不同工况下的流型;给出了水平管内气液两相螺旋流的流型图;研究了不同流速、不同起旋参数对流动特性(压降、流型衰减、螺距、螺旋直径以及流型转换边界等)的影响.实验结论如下:将水平管内气液两相螺旋流的流型划分为螺旋波状分层流、螺旋泡状流、螺旋团状流、螺旋线状流、螺旋轴状流、螺旋弥散流6种;将绘制的流型图与经典Mandhane流型图进行对比,出现了线状流、弥散流和轴状流3种新的流型;泡状流的分布基本不变,层状流的分布发生变化,当气相流速在2m/s以内时是线状流和轴状流,而不是层状流;随着液相流速的提高,管内两相流动的损失逐渐变大,流型的衰减程度变弱,螺旋扭矩逐渐变大,螺旋直径逐渐变小.另外,随着叶轮角度的增大或者随着叶片面积的减小,流型转换边界均向进气量增大的方向推移.而当进气量一定时,随着叶轮角度的增大或者随着叶片面积的减小,同样流型转换边界趋于进水量增大的方向.最后,随着起旋角度的增大或者随着叶片面积的减小,压降均有逐渐变大的趋势.  相似文献   

9.
对团聚体状细颗粒的阻力修正系数进行落球法实验研究,得到颗粒粒径比、团聚体颗粒与流场夹角、规则团聚体颗粒自身夹角和不规则团聚体的分形维数等参数对阻力修正系数的影响。结果表明,团聚体所含颗粒的粒径之比越大,其阻力修正系数越大;团聚体颗粒阻力修正系数随团聚体与流场夹角的增大而增大;团聚体颗粒自身夹角越大,阻力修正系数越大,团聚体颗粒自身夹角越接近0°,其阻力修正系数越接近于1。对于不规则团聚体颗粒,阻力修正系数随分形维数的增大而减小。  相似文献   

10.
不同高度柔性植被对坡面流水动力特性的影响   总被引:1,自引:0,他引:1  
基于系列坡面流试验,研究了柔性植被的高度(4 cm,8 cm和15 cm)对坡面流水动力特性的影响.研究表明:覆盖率相同时,4 cm植被阻水效果最好,15cm最差,而该差异随着坡度增大而减小.4 cm和8 cm植被覆盖时,水流阻力系数随雷诺数增加先减小后增加,这是由于雷诺数较小时水流阻力主要以床面阻力为主,雷诺增大时主要以植被阻力为主.另外,通过染色剂法测得光滑床面平均流速修正系数为0.2~0.4,有植被覆盖床面为0.4~0.8,且修正系数随平均流速增大而增大.  相似文献   

11.
A powerful approximate method for modeling the flow performance of perforated completions under steady-state conditions has been developed. The method is based on the representation of the perforation tunnels surrounding a wellbore by the equivalent elongated ellipsoids. This makes possible an analytical treatment of a 3D problem of steady-state flow in a porous medium with complex multiple production surfaces. The solution is obtained for a vertical wellbore fully penetrating through a horizontal formation in the presence of permeability anisotropy. The perforations are oriented horizontally, arranged in almost arbitrary patterns, repeating along the wellbore, and may have different lengths and shapes. The hydraulic resistances of perforations flowing inside them as well as the crushed zones around them with impaired permeability are neglected. The approximate solution found was verified by comparing the previous analytical/numerical solutions for a small number of perforations. This approach allows one to determine the local skin or the effective wellbore radius for any perforated interval, which can then be integrated into the conventional calculations of well productivity and used for the perforating gun selection during perforation job design.  相似文献   

12.
水平井和水力压裂是页岩气开发中的关键技术。对水力压裂中多簇裂缝同时扩展的物理过程进行了数值模拟。采用扩展有限元法(XFEM)模拟岩石中裂缝沿着任意路径扩展,采用有限体积法(FVM)模拟裂缝中流体的流动,并且考虑井筒中流体流动以及在各簇裂缝间的流量动态分配。通过牛顿迭代对全耦合物理过程进行数值求解,重点研究了初始长度不同的两条裂缝的扩展过程,证明较大的射孔摩阻能促进两条裂缝的同时扩展。并通过算例证明了本方法的精度和有效性。  相似文献   

13.
Direct contact heat transfer between water and a heat transfer oil was investigated under non-boiling conditions in co-current turbulent flow through a horizontal concentric annulus. The ratio of the inner pipe diameter to the outer pipe diameter (aspect ratio) κ = 0.730−0.816; total liquid velocity (mixture velocity) VT = 0.42−1.1 m/s; inlet oil temperature Toi = 38−94°C; oil volume fraction in the flowing mixture φo = 0.25−0.75 were varied and their effects on the overall volumetric heat transfer coefficient Uv were determined at constant interfacial tension of 48 dynes/cm.

It was found that, in each concentric pipe set, the overall volumetric heat transfer coefficient increased with increasing dispersed phase volume fraction at each constant mixture velocity and reached a maximum at around φo = φw ≈ 0.5. The maximum Uv values increased with increasing total liquid velocity and decreasing aspect ratio of the annulus. The volumetric heat transfer coefficient was also found to increase with increasing inlet oil temperature and increasing total liquid velocity but to decrease with length along the test section keeping all other parameters constant. Empirical expressions for the volumetric heat transfer coefficient were obtained within the ranges of the experimental parameters.  相似文献   


14.
为了准确模拟致密油藏水平井大规模压裂形成复杂裂缝网络系统和非均质储层井底压力变化,建立考虑诱导缝矩形非均质储层多段压裂水平井不稳定渗流数学模型,耦合裂缝模型与储层模型得到有限导流裂缝拉普拉斯空间井底压力解,对两种非均质储层模型分别利用数值解、边界元和已有模型验证其准确性.基于压力导数曲线特征进行流动阶段划分和参数敏感性分析,得到以下结果:和常规压裂水平井井底压力导数曲线相比较,理想模式下,考虑诱导缝影响时特有的流动阶段是综合线性流阶段、诱导缝向压裂裂缝“补充”阶段、储层线性流动阶段和拟边界控制流阶段.诱导缝条数的增加加剧了综合线性流阶段的持续时间,降低了流体渗流阻力,早期阶段压力曲线越低;当诱导缝与压裂裂缝导流能力一定时,裂缝导流能力越大,线性流持续时间越长;当所有压裂裂缝不在一个区域时,沿井筒方向两端区域低渗透率弱化了低渗区域诱导缝流体向压裂裂缝“补充”阶段,因此,沿井筒方向两端区域渗透率越低,早期阶段压力曲线越高;当所有压裂裂缝在一个区域时,渗透率变化只影响径向流阶段之后压力曲线形态,外区渗透率越低,早期径向流阶段之后压力曲线越高.通过实例验证,表明该模型和方法的实用性和准确性.  相似文献   

15.
The pressure drop has a significant importance in multiphase flow systems. In this paper, the effect of the volumetric quality and mixture velocity on pressure drop of gas-liquid flow in horizontal pipes of different diameters are investigated experimentally and numerically. The experimental facility was designed and built to measure the pressure drop in three pipes of 12.70, 19.05 and 25.40 mm. The water and air flow rates can be adjusted to control the mixture velocity and void fraction. The measurements are performed under constant water flow rate (CWF) by adding air to the water and constant total flow rate (CTF) in which the flow rates for both phases are changed to give same CTF. The drift-flux model is also used to predict the pressure drop for same cases. The present data is also compared with a number of empirical models from the literature. The results show that: i) the pressure drop increases with higher volumetric qualities for the cases of constant water flow rate but decreases for higher volumetric qualities of constant total flow rate due to the change in flow pattern. ii) The drift-flux model and homogenous model are the most suitable models for pressure drop prediction.  相似文献   

16.
A micropolar model for blood simulating magnetohydrodynamic flow through a horizontally nonsymmetric but vertically symmetric artery with a mild stenosis is presented. To estimate the effect of the stenosis shape, a suitable geometry has been considered such that the horizontal shape of the stenosis can easily be changed just by varying a parameter referred to as the shape parameter. Flow parameters, such as velocity, the resistance to flow (the resistance impedance), the wall shear stress distribution in the stenotic region, and its magnitude at the maximum height of the stenosis (stenosis throat), have been computed for different shape parameters, the Hartmann number and the Hall parameter. This shows that the resistance to flow decreases with the increasing values of the parameter determining the stenosis shape and the Hail parameter, while it increases with the increasing Hartmann number. The wall shear stress and the shearing stress on the wall at the maximum height of the stenosis possess an inverse characteristic to the resistance to flow with respect to any given value of the Hartmann number and the Hall parameter. Finally, the effect of the Hartmann number and the Hall parameter on the horizontal velocity is examined.  相似文献   

17.
The underground contour of an embedded rectangular dam, whose corners are rounded in accordance with curves of constant flow velocity and whose water-permeable base is underlain by a confining layer with a curvilinear roof characterized by a constant flow velocity, is constructed. The corresponding boundary value problem is solved by means of the semi-inverse use of the velocity hodograph method. The results of the numerical calculations are given and the effect of the main determining parameters of the model on the shape and dimensions of the underground contour of the dam and the curvilinear confining layer is analyzed. The limiting cases in which the water-permeable base of the dam has an unbounded thickness, namely, a streamlined apron with a horizontal insert and streamlined sheet piling (tooth), are investigated in detail.  相似文献   

18.
水平井砾石充填数值模拟研究进展   总被引:1,自引:0,他引:1  
综述了水平井数值模拟研究的最新进展,内容包括:水平井砾石充填 机理及技术难题、充填过程中平衡砂床高度、临界流速的计算模型,描述了筛管/井筒环空砂 浆流动、冲管/筛管环空纯携砂液流动以及它们之间流体的交换和向地层的滤失过程. 重点介 绍了$\alpha$波充填过程中流动数学模型的研究现状及影响水平井砾石充填的各个 因素和存在的问题.  相似文献   

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