水平气井临界携液流量预测新方法

A NEW PREDICTING METHOD OF THE CRITICAL LIQUID-LOADING FLOW RATE FOR HORIZONTAL GAS WELLS

针对水平气井连续携液机理不清、临界携液流量计算误差较大等问题,基于水平气井连续携液的实验结果,首先对水平井筒中的液膜和中心气流进行受力分析,综合考虑液膜稳定存在和连续携液这两方面,建立了水平气井的临界携液流量预测新模型,并给出相应的修正因子。敏感性分析表明:在水平气井中,修正因子主要由油管内径、液相黏度和举升因子决定;随着油管内径与液相黏度的不断增大,临界携液流量也相应增大;而随着举升因子的增大,临界携液流量随之减小。实例研究表明:新模型的计算结果相对误差小于10%,比常用计算模型提高精度10. 5%~62. 8%;计算结果与现场实际数据吻合度更高,可用来准确预测水平气井的临界携液流量。新模型对提高水平气井的最终采收率具有指导作用。

In the light of the problems of the unclear mechanism of continuous liquid loading,rather bigger calculated error of the critical liquid-loading flow rate and so on for the horizontal gas wells,on the basis of the experimental results of the continuous liquid load-up for the wells,the force was first analyzed for the liquid film and central gas flow in the horizontal wellbore,considering the two aspects of the stable existence of the film and continuous liquid load-up,the new predicting model of the critical liquid-loading flow rate was established for the horizontal gas wells,at the same time,the corresponding correcting factors were presented. The sensitivity analysis shows that in the gas wells,the correcting factors are mainly determined by the inner diameter of the oil tubing,the viscosity of the liquid phase and the lifting factor; with the rises of the inner diameter and the viscosity,the critical liquidloading flow rate is correspondingly increased; while with the rise of the lifting factor,the rate stated above is decreased. The history case study proves that the relative error of the calculated results by the new model is less than10%,comparing with the common calculating model,the precision can be enhanced by 10. 5%-62. 8%; there is pretty higher matched degree between the calculated results and the field actual data,so the critical liquid-loading flow rate can be correctly predicted. The new model possesses a certain guiding action for enhancing the ultimate recovery of the horizontal gas wells in the field.