METHODS AND SYSTEMS FOR CONTROLLING VISCOSITY IN REAL TIME

Systems and methods are disclosed for controlling a viscosity of a fluid. The control system includes a controller controlling an input to an actuator and an observer estimating the viscosity of the fluid. The controller includes an input, and the actuator is capable of controlling a viscosity of a fluid by delivering a gelling agent to the fluid. The observer and the controller are coupled together. The observer may be used to determine the viscosity at the current time from a sensor and filter combination that lags the actual viscosity value. The estimated sensor and filter output may be then compared to the sensor and filter output to make corrections to the estimate of the viscosity of the current time.