深井超深井溢流流体密度计算方法

Calculation Method of Overflow Fluid Density in Deep and Ultra-deep Wells

我国油气勘探开发逐渐转向深水、深井、超深井等区域,深层地层复杂且认识不清,钻探过程中溢流漏失等事故频发,对油气勘探开发进程危害极大。处理溢流事故,优选压井方法,首先需要计算溢流流体的密度。目前,相关研究主要是通过经验法或简单的计算模型判别溢流流体的种类,该模型并未考虑温度压力的影响,存在一定误差。文章考虑了温度压力以及两相流模型的影响,基于U型管效应,建立了一种计算溢流流体密度的修正方法。该方法应用简单,经过现场验证,准确率高达95%以上,计算精度高于传统方法,溢流流体种类判别准确率高,对现场处理溢流事故、优选压井方法以及溢流后的控压钻井具有指导意义。

China′s oil and gas exploration and development has gradually shifted to deep water,deep wells,ultra-deep wells and extra deep wells.In these areas,the complex formation is unclear,overflow and lost circulation events occur frequently,which causes great harm to the process of oil and gas exploration and development.To deal with overflow event and select the optimal well killing method,the first step is to calculate the density of overflow fluid.At present,related studies mainly judge the types of overflow fluid through empirical method or simple calculation model,which does not consider the influence of temperature and pressure and has some errors.Considering the temperature pressure and the two-phase flow model,a modified method to calculate the overflow fluid density based on the U-tube effect is established.This method is simple to use,and the accuracy of the field data is up to 95%.The calculation accuracy is higher than the traditional method.This method has its guiding significance for dealing with overflow events,selecting the optimal well killing method and MPD operation after overflow.