大斜度井注水泥顶替界面理论模型分析与数值求解

Analysis and numerical solution of cementing displacement interface theoretical model in highly deviated well

保持注水泥顶替界面稳态可有效保证注水泥顶替效果。该文以非牛顿流体在井眼环空流动特性为基础,参考顶替界面处的连续性条件,对建立的偏心环空注水泥顶替界面理论模型进行分析和有限差分求解。结果表明:在大斜度井内,一定的套管偏心可抑制水泥浆在环空低侧宽间隙内的突进,有利于保持顶替界面的稳定。该模型适用于不同井斜角条件偏心环空内的注水泥顶替界面形态,可为注水泥顶替参数和流体性能参数优化设计提供一定的理论依据和参考。

Keeping cementing displacement interface steady can guarantee cementing quality effectively. Based on non-Newtonian fluid flow characteristics in the annulus, the displacement interface theoretical model is founded after the continuity conditions are considered. The model can be solved by finite difference method and the results show that a certain casing eccentricity can stop the fingering in the widest annular gap （usually at the low of the wellbore） and help maintain the displacement interface stability in highly deviated well. The displacement interface model can be used to imitate displacement interface states in eccentric annulus of wellbores with different deviation angles, which offer certain theoretical foundation and reference for optimizing designs of the displacement parameters and performance parameters.