Chevron Texaco has 13 wells producing offshore Africa by use of electrical submersible pumps (ESPs) that have experienced problems primarily because of the transient nature of the multiphase inflow through the sinusoidal well-path profiles. A transient multiphase simulator modeled the sinusoidal sections of each producer and calculated conditions that the ESPs might encounter over the life of the well for various drawdown conditions and speeds. The results were used to reduce operational downtirne and improve ESP-completion designs.