The Effect of Heterogeneity of Reservoir on Recovery in Waterflooding

摘要

In multi - layer heterogeneity reservoir, the character of each layer differs greatly (such as porosity, permeability and fracture, etc), so does the water absorption capacity of each layer when water drive is adopted. Thus the adsorption profile of injection well, in great heterogeneity, which causes those layers of high porosity and fracture watered- out quickly, makes production well producing difficult, and makes the formation pressure decreasing rapidly due to the energy loss underearth. Therefore, how to thicken the accepting water layer and reduce the water -absorption- heterogeneity among each layer must be taken into account. Besides, under the action of injected water pressure, a part of oil can not be displaced due to viscosity resistance and capillary pressure. They are trapped in pores of rock thus the recovery is affected. Therefore, to conquer the negative effects that the heterogeneity of reservoir exerts on the improvement of oil recovery, it is quite important to discuss the profile control of injection well and water plugging of producing well, and research the mechanism of the remaining oil both existence and replacement. Injecting water to oil layer to make up the void due to exploit, thus complimenting the energy of layer and maintaining formation pressure to recovery, oil is called waterflooding recovery. Both confined by the geographic conditions and exploit level, the recovery efficiency is only about 40% on average, about 60% oil remained. This paper will study how to improve conformance efficiency and oil displacement efficiency so as to enhance the oil recovery.