连续管作业气液两相流多模型组合计算方法

Gas-Liquid Two-Phase Flow Combined Model for Coiled Tubing Operation

目前连续管作业井筒气液两相流压力计算以单一模型为主,该模型难以有效模拟整个井筒的实际流动状况,亟需解决单一气液两相流动模型仅适用于一种流动工况,与实际井筒同时存在多种流动工况两者难以匹配的问题。为此,通过试验数据建立不同流动工况下的最优流动模型,在此基础上形成多模型组合优化的气液两相流计算方法。该方法能够针对不同的流动工况将整个井筒(管内/环空)合理划分为多个井段,每个井段采用对应流动工况下的最佳气液两相模型,最终完成整个井筒的压耗计算。通过将环空压力与泵压的相对误差分别与其他5种单一气液两相模型相比可知,优化模型综合平均相对误差最低为8.23%。该方法可为连续管作业施工方案的合理设计提供理论参考。

A single model is usually used for calculating the gas-liquid two-phase flow pressure in wellbore with coiled tubing(CT)operation.However,this model is only applicable to one flow condition in the wellbore,but cannot effectively simulate the actual multiple flow conditions in the whole wellbore.In this paper,the optimal flow model for each flow condition was built using the test data,and accordingly an optimized gas-liquid two-phase flow combined model was formed.This combined model can divide the whole wellbore(in string/annulus)into multiple sections depending on flow conditions.The optimal gas-liquid two-phase model for corresponding flow condition is used for each section,and ultimately the pressure loss calculation is completed for the whole wellbore.The combined model was compared with each of the five optimal models in terms of relative error between annulus pressure and pump pressure.It is found that the average relative error of the combined models is 8.23%.This proposed combined model provides a theoretical reference for the rational design of CT operation plan.