基于卡森流体的水平井波动压力预测新方法

New Prediction Method on Surge Pressure in Horizontal Well Basing on Casson Fluid

针对水平井钻井过程中产生的波动压力问题提出了一种新的预测方法。以钻井流体力学理论为基础,阐述了水平井环空波动压力的流动物理模型,考虑管柱偏心对钻井液流动规律的影响,从一维稳定流动的基本方程和卡森模式的本构方程出发,引入卡森流体在水平井偏心环空轴向层流的流量模型,进而结合管柱在不同现场工况下的环空流量方程,使用mathematica软件进行数值模型的计算,最终建立了预测水平井各个井段波动压力的新模型。实例计算表明:该方法计算简单快捷,预测准确,对水平井钻井过程中的安全控制具有重要的指导意义。

In this paper, a new prediction method is established to predict the surge pressure in horizontal well drilling. It is based on the drilling fluid mechanics, describing the flowing physical model towards surge pressure in horizontal well annulus, and taking the effect on the flowing law of drilling fluid made by eccentricity into consideration. Due to the constitutive equation of one-dimensional steady flow and Casson-mode, the axial laminar flowrate models of eccentric annulus of Casson-fluid, and equations of annulus flowrate under different drill string working conditions, the new model for surge pressure prediction numerical model for each section in horizontal well is established by a software Mathematica. Applications show that the method has a critical positive affection on horizontal well operation.