起下钻引发的环空瞬态波动压力计算方法

Improved Calculation of Transient Surge Pressure in Wellbore while Tripping Operations

准确计算并预测井筒波动压力对保证钻井安全至关重要。通过井筒流道分析,建立了井筒环空瞬态波动压力计算模型,采用特征线法进行数值求解,获得了环空波动压力值及波动压力的时间分布特征。以现场一口井为基础数据进行下钻过程计算。结果表明:压力波以弹性波的形式在井筒流道内进行传播;随着钻杆运行速度的增加,环空中瞬态波动压力增加。现场钻井作业过程中,在保证钻井安全的前提下,可通过降低钻井液密度、减小起下钻速度以减小瞬态波动压力的影响。

Accurate calculation and prediction of wellbore transient surge pressure is essential to ensure drilling safety.Through the analysis of the wellbore flow path,a calculation model of the transient surge pressure in the wellbore annulus was established.The characteristic line method was used for numerical solution,and the transient surge pressure value and the time distribution characteristics of the transient surge pressure in the annulus could be obtained.The calculation results of the drilling process based on the data of a well on site show that the pressure wave propagates in the wellbore flow channel in the form of elastic wave.As the operating speed of the drill pipe increases,the transient surge pressure in the annulus increases.During on-site drilling operations,under the premise of ensuring drilling safety,the impact of transient pressure fluctuations can be reduced by reducing the density of the drilling fluid and the tripping speed.