Unsteady-State Models

In nearly all applications, the steady-state models discussed in the previous section are not adequate in describing the water influx. The transient nature of the aquifers suggests that a time-dependent term be included in the calculations for W_e. In the next two sections, unsteady-state models for both edgewater and bottomwater drives are presented. An edgewater drive is one in which the water influx enters the hydrocarbon bearing formation from its flanks with negligible flow in the vertical direction. In contrast, a bottomwater drive has significant vertical flow.