具有拐点的油井IPR方程建立及应用

Establishment and application of inflow performance relationship with an inflection point

油藏开采过程中,当流动压力低于饱和压力时,溶解于原油中的天然气析出,水驱油藏油井出现三相渗流,部分油井受其影响,产量出现随着流动压力降低而下降的现象,表现为IPR曲线发生倒转。利用新建立的油井流入动态关系方程,能够合理地拟合和描述这种倒转现象,并可以判断油井IPR曲线是否出现倒转现象或具有拐点,计算油井的最低合理流动压力。新建立的IPR方程通式囊括了大部分经典的IPR方程,包括经典的Vogel方程和Fetkovich方程及其推广式,具有较强的实用性。

Dissolved gas will come out from oil in producing process when flowing pressure is lower than bubble point pressure,thus appeared three-phase flow in oil wells of water flooding reservoir,and oil production will decrease with the drop of flowing pressure,showing inversion of IPR curve. A newly established inflow performance relationship can reasonably match and describe the inversion,judge whether there will be an inversion or inflection point on IPR curve,and calculate the minimum reasonable flowing pressure in oil wells. The new IPR involves most of the classical IPR equations,such as Vogel and Fetkovich equations and their generalization formula,so it is highly practical.