Nonlinear optimization and control of an Electric Submersible Pump lifted oil field

In an Electric Submersible Pump (ESP) lifted oil field, the ESP of each oil well should be operated inside its operating window. The total power consumed by the ESPs in the oil field should be minimized. The speed of the ESPs and the production choke valve opening should be optimally chosen for maximizing the profit from the oil field. At the same time, the capacity of the separator should not be exceeded. In this paper, a nonlinear steady state optimizer is developed. The optimal pump speed and the optimal fluid flow rate through each oil well are controlled by two separate PI controllers. The paper shows that the production choke valve for each oil well has to be always 100% open to maintain the optimal fluid flow rate. The limitation of the optimal control structure for very low values and for very high values of the separator capacity has been discussed.