As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE NR 2 ENGINE OIL QUANTITY STEADILY DECREASED FROM APPROX 5.6 GALLONS TO ZERO WITHIN 45 MINUTES FROM TAKEOFF. SHUT DOWN ENGINE AND RETURNED TO AMS. WINDMILL TIME 1 HOUR 16 PSI OIL PRESSURE. FOUND OIL LEAK TO BE INTERNAL REMOVED AND REPLACED ENGINE PER BOEING MAINTENANCE MANUAL 71-00-02.