Wave structure in WAG recovery

In immiscible three-phase flow, the lead oil bank can split into two, a Buc kley-Leverett shock wave followed by a new type of shock wave. Such a noncl assical "transitional" shock wave is common in three-phase flow. Its sensit ivity to diffusion implies that capillary pressure must be modeled correctl y to calculate the flow. In particular, transitional shock waves arise in w ater-alternating-gas (WAG) flow. They can be calculated by semi-analytic me thods, which are helpful in the design of effective WAG recovery strategies .