Abstract: The production fluid emulsification is a usual type of formation damage. Electrical submersible pump (ESP) shear action may result in or intensify production fluid emulsification. It gets more difficult to determine whether the production fluid emulsification is caused before the production fluid flows into wellbore or when it is in the wellbore. Using the continuity equation, momentum equation, energy equation for oil-gas-water multiphase fluid, a dynamic theory model taking shearing into account is established. After substituting the components of each phase, a multi-phase fluid dynamic model is established for oilfield production fluid. Then the actual production fluid data is substituted, so a mathematic model suitable for oilfields is established. The production fluid of 5 wells is calculated, which approaches to the real production fluid. It indicates that the model is appropriate. The relationship between the well depth and the well fluid pressure distribution is predicted when the water cut of the five typical wells of the oilfield is 0, 20%, 40%, 60%, and 80%. The result shows that the energy consumption before pump is lower than that after pump when enhancing unit well fluid, that is, emulsification of produced fluid is intensified by ESP. It gets easier to determine whether the formation damage is caused by production fluid emulsification.