Automated pump control of a cementing unit of wellsite equipment

1. A method comprising:

establishing communication between a cementing unit and a controller operable to control operation of the cementing unit, wherein the controller comprises a processor and a memory including computer program code; and

operating the controller to automatically perform a flow rate calibration of the cementing unit, wherein the flow rate calibration comprises automatically:

varying pumping speed of the cementing unit while recording the pumping speed and a corresponding flow rate generated by the cementing unit, wherein varying the pumping speed of the cementing unit comprises increasing the pumping speed of the cementing unit based on a first incremental percentage set-point until a volume of cement pumped by the cementing unit is substantially equal to a fluid volume set-point, and decreasing the pumping speed of the cementing unit based on a second incremental percentage set-point until the cementing unit stops pumping the cement; and

determining a flow rate ramp relating the recorded flow rates to the corresponding recorded pumping speeds.

2. The method of claim 1 further comprising inputting the fluid volume set-point, and wherein varying the pumping speed comprises:

increasing the pumping speed of the cementing unit while recording the pumping speed and the corresponding flow rate generated by the cementing unit until the fluid volume set-point is met; and

decreasing the pumping speed of the cementing unit while recording the pumping speed and the corresponding flow rate generated by the cementing unit until the cementing unit stops pumping the cement.

3. The method of claim 2 further comprising inputting first and second incremental speed set-points, wherein the pumping speed is increased by the first incremental speed set-point until the fluid volume set-point is met, and wherein the pumping speed is decreased by the second incremental speed set-point until the cementing unit stops pumping the cement.

4. The method of claim 3 wherein:

the recorded flow rates and corresponding recorded pumping speeds are first recorded flow rates and first recorded pumping speeds;

the flow rate ramp is a first flow rate ramp;

the method further comprises inputting the first incremental percentage set-point, the second incremental percentage set-point, a fluid flow rate set-point, and the fluid volume set-point; and

varying the pumping speed further comprises, after estimating the first flow rate ramp:

increasing the pumping speed of the cementing unit by a speed corresponding to the first incremental percentage set-point of the fluid flow rate set-point based on the first flow rate ramp while recording second pumping speeds and corresponding second flow rates generated by the cementing unit until the fluid volume set-point is met;

decreasing the pumping speed of the cementing unit by a speed corresponding to the second incremental percentage set-point of the fluid flow rate set-point based on the first flow rate ramp while recording third pumping speeds and corresponding third flow rates generated by the cementing unit until the cementing unit stops pumping the cement; and

determining a second flow rate ramp relating the second and third recorded flow rates to the corresponding second and third recorded pumping speeds.

5. The method of claim 1 wherein the flow rate calibration further comprises, before varying the pumping speed:

confirming that the cementing unit is not pumping;

confirming that the cementing unit is depressurized;

confirming that a sufficient volume of fluid is available for performing the flow rate calibration; and

either:

opening fluid inlet and outlet valves of the cementing unit; or

confirming that the fluid inlet and outlet valves of the cementing unit are open.

6. The method of claim 1 further comprising operating the controller to automatically confirm that safety parameters are within corresponding predetermined ranges during the flow rate calibration.