基于ANSYS的金刚石钻头钻进中孔底岩石的热交换研究

摘要

Reasonable heat exchange is helpful to stress development and fracture of hole-bottom rock.However, the heat exchange of hole-bottom rock is a complex dynamic process, so it is difficult to use a mathematical model to solve. Therefore, in this paper finite element method was employed to establish model of hole bottom rock heat exchange; the temperature distribution in bottom rock and its changes with time and bit parameter were analyzed with ANSYS software, and the basic heat exchange law of hole bottom rock was obtained. The simulation results showed that the temperature oscillation existed in bottom rock surface layer (shallower than 1.0 mm )during diamond drilling , whose waveform was approximated to a sine wave;however, with the increase in depth the amplitude of temperature oscillation decreased sharply, while with increasing waterway length, the depth of temperature oscillation increased linearly.%合理的井底岩石热交换有助于岩石表面应力的发育,从而有利于提高钻进效率.但孔底岩石热交换是一个复杂的动态变化过程,很难用一个数学模型进行量化求解.基于此,本文采用有限元方法,对孕镶金刚石钻头钻进过程中的孔底岩石热交换问题进行了建模,并利用ANSYS软件对孔底岩石表层温度分布及其随时间、钻头参数的变化规律进行了分析,得出了孔底岩石热交换的基本规律.仿真结果表明:金刚石钻进过程中岩石表层内(厚度一般小于1 mm)存在温度振荡,振荡波形近似为正弦波,但随着深度增加温度振幅急剧变小;而随着水口的增大,振荡深度呈线性增加.