井底脱气半径方程建立及影响因素分析

The Value of Degassing Radius Solution and Affecting Factors Analysis after Well Degassing

当压力低于饱和压力后,原油会在地层脱气,在井筒附近形成三相流,影响油井产量。针对大多数油井在生产过程中仅在井底附近局部脱气的现象,根据渗流力学理论,建立油井脱气半径的计算公式,重点分析地层压力、井底流动压力、含水率对脱气半径的影响。研究结果表明,油井脱气半径随井底流压和地层压力的降低而逐渐增大,当地层压力降至饱和压力时,脱气半径等于供给半径;含水率对脱气半径的影响远小于地层压力和井底流压的影响,生产过程中可忽略不计。

In the process of oil well production,crude oil degassing will happen in reservoir when the pressure is lower than the saturation pressure,which leads to three- phase flow near wellbore,bringing a strong impact on oil production. In view of this phenomenon of many oil wells degassing happened near bottom- hole area,a method of calculating degassing radius was established according to the theory of percolation mechanics in this paper. It also focused on some factors that influenced the saturation pressure,including the formation pressure,the flowing bottom- hole pressure and the water cut. The results show that with the decreasing of the flowing bottom- hole pressure and formation pressure,the degassing radius increases gradually. And when the formation pressure drops to the saturation pressure,the degassing radius is the same with the reservoir supply radius. However,the influence of water cut on degassing radius is so small that we can ignore it in the process of oil production.