The invention relates to a heavy
oil displacement method using a wedged vicious
slug. The method includes the steps of 1, dividing a nonhomogeneous reservoir into a plurality of
layers according to water absorbing capacities, and acquiring permeability Ki of each reservoir; 2, designing three slugs, namely a pre-
slug, a main wedged
slug and a trailed slug, according to the permeabilities Ki and the physical properties in heavy oil and reservoirs; 3, alternately injecting the
heavy oil reservoir with the pre-slug which is prepared with low-concentration B III-type poly-surfactant and which enters a high permeability layer to emulsify
crude oil; 4, injecting the reservoirs with the main wedged slug for multiple rounds; and 5, injecting the trailed slug with low-concentration B III-type poly-surfactant or
fresh water generally. In each round, the main wedged slug is divided into three small slugs; the small slugs in each round are combined by regulating the corresponding concentrations by the B III-type poly-surfactant according to formation permeability. According to the method, the nonhomogeneous heavy oil reservoirs are emulsified to reduce
viscosity, the wedged equivalent vicious slug is used for equi-fluidity displacement, and swept volume is increased; accordingly,
recovery efficiency of heavy
oil can be further increased, investment can be reduced and operation can be simplified.