井下它激自增流量理论及数值模拟

【作者】 钱声华；

【导师】 熊继有；

【作者基本信息】 西南石油学院 ， 油气井工程， 2004， 硕士

【摘要】 对于如何利用井底水力能量的问题，目前正在进行探索性研究。利用井下水力能量是国际石油界的一个重大理论研究课题和实践问题，是提高钻井速度，降低钻井工程成本的新思维、新概念及21世纪的必然发展趋势。本文所研究的内容是属于在2003年获得国家自然基金资助的项目《西部深井井下水力增压及高效破岩理论研究》的一部分，主要是通过对自激振荡腔室及它激振荡腔室内的流场进行数值模拟分析，弄清了它激振荡腔室的自增流量的机理，并找出了自增流量与各个影响因素之间的关系。 通过对振荡腔室内流动特性理论进行研究，建立了适合于自激振荡腔及它激振荡腔内流场的数学模型，然后利用ANSYS的流体动力学软件进行了三维腔室流场的数值模拟计算。 自激振荡腔室内的流场是一种轴对称的紊动射流问题，我们运用流体动力学软件对腔室内流场的压力进行了数值模拟研究，分析了腔室结构及流体性质对腔室内压力的影响关系，找出了影响腔室内压力的主要因素有流量、喷嘴直径比值、流体的密度和流体的粘度。 自增流量装置就是利用自激振荡腔室内的负压力，引入环空的流体形成它激振荡，达到自增流量的目的。在进行它激振荡腔室内流场的模拟计算中，我们采用单因素分析的方法，分别对入口流量、上下喷嘴直径比值、腔室长度、腔室直径、它激孔直径、流体介质的密度、流体介质的粘度，这七项作了研究，得出了影响腔室自增流量的最主要的两个因素是上下喷嘴直径比值和入口流量。当喷嘴直径比值r=1.5时，自增流量为最大；自增流量大小与入口流量几乎呈线性变化的关系。 根据数值模拟的结果，得出了它激振荡腔室自增流量的经验公式，为了便于对它激振荡腔室进行优化设计，我们利用这些经验公式编制了自增流量的计算程序。更多还原

【Abstract】 The problem about how to make use of the downhole hydraulic power is researched exploringly. As an important theoretical and practical subject in the world petroleum area, it is a new idea, a new conception and an inevitable tendency for increasing the drilling rate and decreasing the drilling cost. This paper is part of the project named "the Research about Downhole Pressure-Increasing by Hydraulic and High Efficiency Rock-Cutting Theory for the Deep Well in West of China" which has been supported by the National Natural Science Fund in 2003. In this paper, through the numerical simulation analysis of the flow field in the self-excited oscillation and external-excited oscillation cavity, the mechanism of self-increasing flow in external- excited oscillation cavity was clarified and the relation between the self-increasing flow and the related factors was discovered.By the study of the theory about flow characteristic in the cavity, the mathematical model applied in the flow field of the self-excited oscillation and external-excited oscillation cavity was established, then the numerical simulation about three-dimensional flow field is carried on through the fluid dynamics software of ANSYS.The flowing field in self-excited oscillation cavity is a kind of axial-symmetrical turbulent jet flow. Through the fluid dynamic software, we studied the pressure in the flowing field of the cavity with the numerical simulation method, and analyzed the relation between the pressure of the cavity and the structure of cavity and quality of the fluid. And we found out that the main factor related to the pressure are flow rate, the ratio of jet nozzle diameters, the density and viscosity of the fluid.The device for self-increasing flow was just utilize the under pressure in the self-exciting oscillation cavity to introduce the annular fluid leading to the external excited oscillation. While simulated and calculated the flowing field in the external excited oscillation cavity, we applied the mono-factor method and analyzed the seven factors, such as entry flow rate, the ratio of upper and lower jet nozzle diameter, the length of the cavity, the diameter of cavity, the diameter of the external-excited hole, the density and viscosity of the fluid. Then we found that the primary factors influence the self-increasing flow are the entry flow and the ratio of jet nozzle diameters. The self-increasing flow is most while the ratio of jet nozzle diameters is 1.5. The relation between self-increasing flow and the entry flow is linearity.According to result from numerical simulation, we found out the experiential formulas of the self-increasing flow. In order to convenient to optimize self-excited oscillation cavity, we programmed a program making use of these formulas.更多还原