不同倾角起伏管油气水三相流动特性数值模拟

Numerical simulation on flow characteristics of oil-gas-water three phase flow in undulating tube with different incidence angles

随着水平井和大斜度井的广泛应用,对起伏管内油气水三相流的研究变得异常重要。通过VOF模型模拟不同含气率和倾角下三相流在起伏管中的流动特性,对流型渐变趋势、截面持气率、持水率及井筒内压力分布进行了分析比较。结果表明,低含气率下,起伏管中流型由分层-分层流转化为间歇-分层流,随着倾角的变大,局部持气率变大,持水率变小,压降曲线震荡加强,气弹的存在引起了压降曲线的波动;较高含气率下,其流型基本不变仍为分层-分层流,起伏管拐角处有周期性"液塞"的存在,倾角对持气率的影响作用减弱,倾角越大气液两相滑脱作用越强烈,井筒内压降越大。

With the widely application by the horizontal well and highly-deviated well,it becomes more and more important for studying affecting factors of the flow characteristics of oil-gas-water three phase flow in undulating tube.The VOF model is used to simulate the flow characteristics of three phase flow in big diameter,and simulating the flows condition of the undulating tube under different angle and gas content.then the trend of evolution of the flow pattern,and the gas hold-up,the water hold-up of wellbore section and the wellbore pressure distribution are analyzed and compared.Result shows that in lower rate of gas,the flow pattern of layered-stratified flow is translated to intermittent-stratified flow in undulating tube,with the inclination angle becomes larger,the gas hold-up increase or the water hold-up decrease,pressure drop curve shock strongly,the existence of gas bombs cause the wellbore pressure fluctuations;in higher rate of gas,the flow pattern in the undulating tube constantly is layered-stratified flow,the impact in angle to the gas holdup is abate,but with the inclination angle becomes larger,the slippage effect of atmospheric-liquid two phase is stronger,within the pressure drop in the wellbore is greater.