低渗-特低渗油藏非稳态油水相对渗透率计算模型

Unsteady-state model for calculating oil-water relative permeability for reservoirs with low and ultra-low permeability

关键词:  油藏  低渗-特低渗油藏  非稳态  油水相对渗透率  启动压力梯度  毛管力  重力

Key words:  reservoir  low and ultra-low permeability reservoir  unsteady-state  oil-water relative permeability  threshold pressure gradient  capillary pressure  gravity

摘要:

考虑低渗-特低渗储层多孔介质中油水渗流特征,建立考虑启动压力梯度、重力及毛管力影响的低渗-特低渗油藏非稳态油水相对渗透率计算模型,进行非稳态油水相对渗透率试验,计算不同影响因素下的油水相对渗透率曲线。结果表明,启动压力梯度作为油水渗流的阻力,对油水相对渗透率、储层压力、剩余油饱和度、产油及产水等影响最为显著,其次是重力,毛管力仅对油相相对渗透率有影响,对水相相对渗透率无影响。

Abstract:

Based on the characteristics of oil and water flow in porous media, a model for calculating oil-water relative permeability for oil reservoirs with low and ultra-low permeability was developed, in which the effects of threshold pressure gradient, gravity and capillary pressure were considered. A unsteady state method was used to conduct the measurement of the relative permeability, and the relative permeability curves influenced by various factors were then calculated. The results show that the threshold pressure gradient has a prominent effect on the oil-water relative permeability, formation pressure, residual oil saturation, and the recovery of oil production. The gravity also has important effect on the relative permeability and oil production, while the capillary pressure can affect the oil relative permeability, but it has little influence on the water relative permeability.