幂律流体在内管做行星运动的环空中流动的二次流

建立了运动双极坐标系下幂律流体在内管做行星运动的环空中流动的控制方程,并用有限差分法对其进行了数值求解,得到了该流动的流函数分布.结果表明:幂律流体在内管做行星运动的环空中流动时出现二次流,且二次流分布与环空内管公转、自转速度的方向和大小以及环空偏心距有关.     

P110钢抗冲刷腐蚀行为研究

采用高温高压釜,利用扫描电子显微镜(SEM)、能散X射线谱仪(EDS)和X射线衍射(XRD)技术,并辅以失重法对油套管钢P110在不同条件下的CO2腐蚀速率和行为进行了研究,探讨了在流动介质中多种因素对油套管钢腐蚀造成的影响,并以此提出了P110钢抗冲刷腐蚀的机理.     

变梯度控压钻井井控过程中井口回压变化规律

为了准确掌握变梯度控压钻井井控过程中井口回压的变化规律,采用考虑密度突变的井筒气液两相变质量流动模型,分析了基于井底恒压的变梯度控压钻井井控过程中井口回压的变化,探讨了不同因素变化对井口回压的影响,并开展了最大井口回压影响因素敏感性分析。研究发现：变梯度控压钻井在控制井底压力恒定时井口回压的调节受气体膨胀、分离器位置处液相密度突变、套管鞋及海底泥线处环空变径等多个因素综合影响,其变化规律更加复杂;其他条件不变时,分离器与钻头间距越小、轻/重质钻井液密度差越大、地层压力越大、循环排量越小,循环排气过程中的井口回压越大;对于最大井口回压而言,地层压力、轻/重质钻井液密度差、分离器与钻头间距、循环排量的比变异系数值依次减小,敏感性程度也随之降低。研究结果可为变梯度控压钻井井控过程中的井口回压准确预测和井筒压力精细控制提供理论支撑。     

椭圆井眼同心环空赫巴流体流动规律研究及压降计算简化模型

因岩石和地应力的非均匀性易形成椭圆井眼,导致现有规则圆形井眼环空流动模型存在较大误差.为明确椭圆井眼同心环空赫巴流体流动规律,建立了解析模型和Fluent仿真模型,分析椭圆井眼对环空流速和压降梯度的影响规律;通过修正水力直径和引入有效黏度的方法建立了椭圆井眼同心环空压降计算简化模型,实现流动压降的准确快速预测,并利用解...     

工业CT断层序列图像三维重建的实现

文中对ICT序列断层图像进行三维结构的重建和显示。先对图像进行预处理，去掉空气环，然后再利用Matlab功能强大的函数用体绘制方法进行断层序列图像的三维重建，对某一工业CT机提供的实测数据进行了三维重建，实验结果比较理想。     

Mechanical Stretch-Induced NLRP3 Inflammasome Expression on Human Annulus Fibrosus Cells Modulated by Endoplasmic Reticulum Stress

Excessive mechanical loading is a major cause of spinal degeneration, typically originating from a tear in the annulus fibrosus (AF). Endoplasmic reticulum (ER) stress and NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3) inflammasome have been implicated in the pathogenesis of intervertebral disc (IVD) degeneration. However, the causal relationship between the mechanical stretching of AF cells and the NLRP3 inflammasome response associated with ER stress remains scarce. To elucidate the pathogenesis and regulatory mechanisms of mechanical stretch-induced IVD degeneration, human AF cell lines were subjected to different degrees of cyclic stretching to simulate daily spinal movements. Our results indicated that 15% high cyclic stretch (HCS) induced the expression of NLRP3 and interleukin-1 beta (IL-1β) and was also responsible for the increased expression of NADPH (nicotinamide adenine dinucleotide phosphate) oxidase 2 (NOX2) and reactive oxygen species (ROS) in human AF cells. In addition, HCS increased the expression of glucose-regulated protein 78 (GRP78), an ER stress chaperone, which was neutralized with tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor. In addition, HCS was found to induce thioredoxin-interacting protein (TXNIP) expression and NLRP3 inflammasome activation, which can be suppressed by si-NOX2 or the NOX2 inhibitor GSK2795039. Consequently, HCS upregulated ER stress and ROS production, leading to increased NLRP3 and IL-1β expression in human AF cells, and may further accelerate IVD degeneration.     

可精确测量的小井眼随钻测井仪

井底环空压力是小井眼钻井的关键参数，通常的压力降计算方法对小井眼不适用。文章介绍一种新型小井眼随钻测井仪，它能够精确测量井底环空压力以及抽吸和波动引压力效应。     

Application of unsteady couette flow of non-Newtonian power-law fluids in concentric annular wellbore

Fluid flow phenomena that occur when the fluid is confined between two co-axial cylinders, one of which is stationary and the other is moving at a specified velocity, is known as couette flow. Such flow is representative of that which occurs in the borehole annulus where the wall of the wellbore is represented by the stationary cylinder, and the drill string or casing is represented by the moving cylinder. The fluid local velocity is dependent on the velocity of the moving cylinder or pipe.Different mathematical relations have been developed for surge and swab pressure calculations for flow of power-law fluids in the wellbore annulus. The application of couette flow equations and relationships to evaluate the surge or swab pressure has been limited. These equations are either too complex for field use or require much computation for field application.In this study, the motion equations are analytically solved for non-Newtonian power-law fluids. The solutions of the equations are presented in both dimensionless and graphical forms, which are applied to predict the surge or swab pressure encountered when running tubular goods in liquid-filled boreholes. The technique presented here is easy to use and requires minimal computational efforts for determining the surge or swab pressure for an unsteady motion of a moving inner pipe in a concentric annulus. The results of this study show that the magnitude of surge or swab pressure increases with increase in the pipe acceleration.     

考虑材料非线性的环空增压预测模型

为了准确预测深水油气井钻采过程中的环空增压,建立了改进的环空增压计算模型。该模型考虑了材料的非线性性质和套管变形的影响,其中材料的非线性性质包括了流体热膨胀系数和压缩系数随温度、压力变化的性质以及套管弹性模量、热膨胀系数随温度变化的性质。模型中的非线性函数由插值方法获得,并进行了实验验证和误差分析。计算中,将各个环空沿轴向进行分段,并将变温以增量的方式进行加载。通过算例,将该模型与忽略材料非线性性质和套管变形的简化模型进行了对比,讨论了各非线性参数及井筒变温对环空增压预测结果的影响。结果表明,与改进模型相比,简化模型的误差范围为2.51%~26.11%;在变温较小的深水井中,同时忽略材料非线性和套管变形对环空增压影响较小;而井筒变温较大时,忽略材料非线性后造成的环空增压预测误差非常显著;流体膨胀系数对环空增压的预测结果影响最大,若将流体膨胀系数取为常数,则误差达到70%。