A method for repairing a blowout preventer while in an operational configuration at sea using a blowout preventer milling assembly, the method comprising:
- a. lifting the blowout preventer while secured to casings or tubulars and in the operational configuration to a platform;
- b. locking the blowout preventer to the platform;
- c. opening doors of a gasket chamber of the blowout preventer exposing a gasket surface;
- d. sliding a pair of legs into a pair of grooves in the gasket chamber;
- e. attaching the blowout preventer milling assembly to the pair of legs using a plurality of spring loaded mounting assemblies;
- f. inserting a pneumatic spindle with a calibration head into a spindle holder of the blowout preventer milling assembly;
- g. connecting a support frame actuator of the blowout preventer milling assembly to a portable controller and connecting a bridge frame actuator of the blowout preventer milling assembly to the portable controller enabling simultaneous movement along an x-axis and a y-axis of the blowout preventer milling assembly;
- h. connecting the portable controller to a power supply;
- i. calibrating a location of the pneumatic spindle over the gasket surface using the portable controller, wherein the portable controller controlling simultaneous movement along the x-axis and the y-axis by both the support frame actuator and the bridge frame actuator;
- j. obtaining a preset size of the gasket surface from a library of gasket sizes in a portable controller data storage of the portable controller;
- k. replacing the calibration head of the pneumatic spindle after calibration with a cutting head;
- l. connecting the pneumatic spindle with the cutting head to a pneumatic air supply;
- m. activating the pneumatic air supply to provide pressurized air in a range from 85 psi to 95 psi to the pneumatic spindle with the cutting head;
- n. automatically refinishing the gasket surface using the cutting head by simultaneously moving the support frame actuator along the x-axis and the bridge frame actuator along the y-axis, moving the pneumatic spindle in a predetermined pattern over the gasket surface using an identified gasket size bi-directionally;
- o. de-energizing the pneumatic air supply;
- p. disengaging the pneumatic spindle with the cutting head from the de-energized pneumatic air supply;
- q. removing the blowout preventing milling assembly from the pair of legs;
- and
- r. removing the pair of legs from the pair of grooves of the blowout preventer forming a repaired blowout preventer gasket while the blowout preventer is in the operational configuration at sea and while the blowout preventer is in line with casings or tubulars and secured to casings or tubulars of a wellbore.