钻柱自转公转和径向运动诱发牛顿流体流动的流场分析

发布时间：2018-01-21 16:28

本文关键词： 钻柱自转公转径向运动双极坐标有限体积法　出处：《燕山大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,在石油钻井过程中,钻柱是必不可少的井下钻井工具。其长期浸泡在充满钻井液的井眼当中,靠转盘的带动旋转向下钻进,在这一过程当中,钻柱不仅会绕自身的轴线做自转运动,还有可能绕井眼轴线做公转运动并产生径向运动。研究钻柱运动诱发牛顿流体流动的流动规律具有重要作用,能够有效减少由于钻柱涡动和屈曲而导致的钻井事故的出现,从而减少经济损失。目前国内外学者对偏心环空流已经进行了许多研究,并取得了一定的成果,本课题将在前人的研究成果之上,首次将钻柱径向运动考虑在内,建立钻柱自转、公转和径向运动诱发牛顿流体流动的数学模型,并进行求解,以期更好的研究井筒中钻井液的流动规律,为钻柱受力分析提供依据,从而减少钻井事故的出现。本文首先分析了目前国内外学者在偏心环空流研究中存在的问题和不足之处,并针对这些问题和不足提出了本文的研究内容以及研究方法;经过研究分析,以惯性坐标系下的连续性方程和运动方程为基础,建立了非惯性坐标系下的控制方程;通过基本假设,建立了钻柱自转、公转和径向运动诱发牛顿流体流动的数学模型;采用双极坐标,将偏心环空区域转化为了矩形区域;采用适用性较好,且具有明显优势的有限体积法对建立的数学模型进行了离散,得到了离散后的数学方程;采用MATLAB软件,对钻柱自转运动诱发牛顿流体流动的流场进行了分析,求出了轴向速度分布图和切向速度分布图,并且绘制了不同偏心距条件下的速度流线图。采用FLUENT软件对相同工况下的流场进行了分析,绘制了不同偏心距条件下的速度流线图,并将两种方法绘制的流线图进行了对比,经过对比发现这两种方法计算结果相似,同时都发现只有偏心距达到一定的距离要求时才会有二次流出现。
[Abstract]:At present, in the process of oil drilling, drill string is an essential downhole drilling tool. The drill string can not only rotate around its axis, but also rotate around the hole axis and produce radial motion. It is very important to study the flow law of Newtonian fluid induced by drill string movement. It can effectively reduce the occurrence of drilling accidents caused by vortex and buckling of drill string and thus reduce economic losses. At present, many researches have been done on eccentric annular annulus flow at home and abroad, and some achievements have been made. In this paper, based on the previous research results, the radial movement of drill string is taken into account for the first time, and the mathematical model of Newtonian fluid flow induced by rotation, rotation and radial motion of drill string is established and solved for the first time. In order to better study the flow rule of drilling fluid in wellbore and provide the basis for the analysis of drill string force. In order to reduce the occurrence of drilling accidents. Firstly, this paper analyzes the existing problems and deficiencies of domestic and foreign scholars in the research of eccentric annulus flow. In view of these problems and shortcomings, this paper puts forward the research content and research methods; Based on the continuity equation and motion equation in inertial coordinate system, the control equation in non-inertial coordinate system is established. The mathematical models of Newtonian fluid flow induced by rotation rotation and radial motion of drill string are established by the basic assumptions. The eccentric annulus region is transformed into a rectangular region by using bipolar coordinates. The established mathematical model is discretized by using the finite volume method, which has good applicability and obvious advantages, and the mathematical equations after discretization are obtained. The flow field of Newtonian fluid flow induced by rotary movement of drill string is analyzed by MATLAB software, and the axial velocity distribution diagram and tangential velocity distribution diagram are obtained. The velocity streamline diagram under different eccentricity is drawn. The flow field under the same working condition is analyzed by FLUENT software, and the velocity streamline diagram under different eccentricity is drawn. The flow diagram drawn by the two methods is compared. The results of the two methods are similar and it is found that only when the eccentricity reaches a certain distance can there be secondary flow.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE921.2

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