瞬态通用固液两相流模型及其在动态井眼清洁模拟中的应用

The research on transient general solid-liquid two-phase flow model and its application in dynamic hole cleaning simulation

为准确了解岩屑在井眼中的实时运移、积累过程及其变化规律,基于质量守恒和动量守恒方程,考虑岩屑运移流型和流型转换条件,建立了适应流型变化的瞬态通用固液两相流模型;并将其应用于一口窄密度窗口井的动态井眼清洁模拟过程中,实时模拟整个钻井过程中岩屑沿井筒分布情况。研究结果表明:岩屑对环空压力分布有重要影响;成功钻穿窄安全密度窗口井的关键是实时监测岩屑对井筒压力剖面的影响,通过洗井作业清理岩屑,将井底压力控制在安全密度窗口之内。本文结果能够为洗井间隔设计提供理论依据。

In order to understand the real-time solids transportation and accumulation process of cuttings in the whole borehole and its change law accurately,a general transient solid-liquid two-phase flow model is established based on mass and momentum conservation equations,considering solids transport flow pattern and its conversion conditions.It is applied to the dynamic hole cleaning simulation of a narrow density window well to simulate the distribution of cuttings along the wellbore in real time during the whole drilling process.The results show that the cuttings have an important influence on the annular pressure distribution,and the key to successfully drilling through the narrow safety density window is to monitor the influence of cuttings on the wellbore pressure profile in real time.The cuttings can be cleaned up through the well flushing operation,and the bottom hole pressure can be controlled within the safety density window,which provides a theoretical design basis for the well flushing interval design.