What was found
WHILE COMPLYING WITH MEL 24-11-1A WE HAD APU RUNNING CONTINUOUSLY IN FLIGHT. ABOUT 30 MIN INTO THE FLIGHT AT FL250 WE RECIEVED APU OIL PRESS CAUTION. COMPLIED WITH QRH AND LEFT APU RUNNING BECAUSE OF IDG#2 DEFERRAL. ABOUT 10 LATER WE RECIEVED A RIGHT ENGINE LOW OIL PRESSURE WARNING 18 PSI AND DECREASING. DECLARED EMERGENCY. QRH FOR RIGHT ENG LOW OIL UNREADABLE. COMPLETED IN FLIGHT SHUTDOWN AROUND 7000 FT. REMOVED AND REPLACED #2 ENGINE IAW J/C 200-71-00-00. CHECKS GOOD. REF AML 3736868-2 FOR APU