空气钻井随钻井筒温度分布研究

发布时间：2018-04-16 14:31

本文选题：空气钻井 + 钻进过程　；参考：《西南石油大学》2015年硕士论文

【摘要】：空气钻井过程中,井下温度分布是影响井下压力平衡及控制、钻井液的流变性能、摩阻压力、井壁稳定等方面的重要因素,掌握其分布规律对钻井作业安全、快速地进行具有极其重要的意义。但是,目前关于空气钻井温度场分布的计算模型还存在以下问题：未考虑钻头破岩产热、流体流动摩擦产热及钻柱与井壁摩擦产热等主要热源项对井筒温度的影响；用整体对流换热系数代替局部对流换热系数,导致计算结果与实际工况差别较大。为了得到更为准确的空气钻井随钻井筒温度分布计算模型,本文做了以下研究： 1.根据传热学相关理论,基于能量守恒定律,建立了空气钻进过程中地层-环空-钻柱内的综合传热模型。 2.通过分析空气钻进过程中钻头破岩产热、钻柱与井壁摩擦产热及流体流动摩擦产热等主要热源项,得到了钻头破岩过程中的热量分配比、钻柱与井壁摩擦过程中环空气固两相流的携热量及井筒内流体流动摩擦产热量。 3.以纯空气通过环空时的对流换热系数为标准,将气固两相流中的三种具有代表性的模型与空气钻井实际工况对比分析,考虑了钻柱旋转对于对流换热系数的影响,优选出了适合空气钻进过程中环空气固两相流对流换热系数的计算模型。 4.在本文所分析的井筒热源项及对流换热系数基础上,编制了计算软件,得到了不考虑热源项、考虑单因素热源项及多因素热源项时的井筒温度分布曲线,结合曲线中的各个关键点,对热源项对于井筒温度分布的影响进行了分析。本文对空气钻进过程中的热源项进行了系统分析,并对井筒温度计算模型中的各个参数进行了优化,得到了考虑了多个热源项的影响的井筒温度分布曲线,从而使本文的研究结果更符合空气钻进过程的实际工况。
[Abstract]:In the process of air drilling, the downhole temperature distribution is an important factor affecting the downhole pressure balance and control, the rheological performance of drilling fluid, friction pressure and wellbore stability, etc.It is of great significance to proceed quickly.However, there are still some problems in the calculation model of air drilling temperature field at present: the influence of the main heat source items, such as bit breaking heat production, fluid flow friction heat generation and drillstring and wellbore friction heat generation, on wellbore temperature is not considered;The local convection heat transfer coefficient is replaced by the global convection heat transfer coefficient, which leads to the difference between the calculated results and the actual working conditions.In order to obtain a more accurate model of air drilling temperature distribution with the bore, this paper has done the following research:1.Based on the theory of heat transfer and the law of conservation of energy, the comprehensive heat transfer model of formation, annulus and drill string during air drilling is established.2.Based on the analysis of the main heat sources during air drilling, such as the heat generation of drill bit breaking, the heat of friction between drill string and shaft wall and the friction heat of fluid flow, the heat distribution ratio in the process of bit breaking is obtained.The heat carrying capacity of the annular air-solid two-phase flow and the friction heat production of the fluid flow in the wellbore during the friction between the drill string and the borehole wall.3.Based on the convection heat transfer coefficient of pure air passing through annulus, three representative models of gas-solid two-phase flow are compared with the actual conditions of air drilling, and the effect of drill string rotation on convection heat transfer coefficient is considered.A model for calculating convection heat transfer coefficient of annular air-solid two-phase flow during air drilling is selected.4.On the basis of the wellbore heat source term and convection heat transfer coefficient analyzed in this paper, a calculation software is developed, and the wellbore temperature distribution curve is obtained when the heat source term is not considered, the single factor heat source term and the multi-factor heat source term are considered.Combined with the key points in the curve, the influence of heat source term on wellbore temperature distribution is analyzed.In this paper, the heat source term in air drilling process is systematically analyzed, and the parameters in the wellbore temperature calculation model are optimized, and the wellbore temperature distribution curve considering the influence of multiple heat source terms is obtained.Thus, the research results of this paper are more in line with the actual conditions of air drilling process.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE24

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