Experimental Studies On Water Flooding Of Oil In A Heterogeneous Reservoir

Reservoir heterogeneity has a great influence on water flooding recovery ratio, the reservoir physical property parameters will change during the super high water-cut stage. The effect of areal heterogeneity and interlaminated heterogeneity on water flooding recovery were studied by making up a series of self-designed heterogeneous physical models.The water oil displacement results that obtained by using core tandem combination model show that, core tandem combination will affect the recovery of single core. When the core is put in the tandem combination model, its recovery reduces from the injection end to the recovery end, and has nothing to do with its gas permeability. The general recovery of the tandem combination model has good correlation with its equivalent gas permeability. The radial flow recovery could be obtained by calculating the equivalent gas permeability of the model. The recovery is proportional to the equivalent average permeability, inversely proportional to its permeability variation coefficient and more sensitive to the permeability variation coefficient.Two-dimensional heterogeneity water oil displacement experiments show that, the recovery of the plane model that the mainstream line parallel to the sedimentary belt extending direction is less than that of the model that the mainstream line diagonal to the sedimentary belt extending direction. The recovery of the model that the water injected in high permeability region is larger that that of the model that the water injected in low permeability region. Injecting speed affect the recovery, in the range of our experiment, the optimal injecting speed is 0.3mL/min. Cyclic waterflooding can make the final recovery efficiency increase 1.6%~3.6%, and the optimal moment of water injection is when the exit skirt water content is 45%. The short note injection/long note cease strategy is better than the long note injection/short note cease strategy for increasing recovery.The water flooding results of interlaminated heterogeneity physical model show that, when the middle high permeability reservoir were developed commingled, the recovery difference between the two reservoir increases and the general recovery decreases with the permeability contrast increase. Under 0.3mL/min injection speed condition, the recovery increases with the average permeability increasing under the same permeability contrast. The two layer commingled permeability contrast limit is 2.56 for middle-high permeability reservoir and it is 5.30 for high permeability reservoir. The recovery difference between the relative low permeability core and the relative high permeability core decreases and the general recovery increases with the injection rate increasing.The experimental results on property time-varying of the reservoir show that, the gas permeability, bound water saturation, residual oil saturation, oil relative permeability under bound water saturation and water relative permeability under residual oil saturation have a good correlation. The reservoir property time-varying mathematical model was obtained with establishing their relationship by using power law formula fit and the polynomial fit.