The CDUs, Pipestills 11A and 11C, which can both process 75,000 bpd in crude oil, were near normal production levels early on Friday, the sources said. Production on Pipestills 11A and 11C was cut back for work on Thursday to an electrical substation.

The refinery's production dipped below 90 percent of capacity on Thursday because of the work.

CDUs do the initial refining of crude oil coming into a refinery and provide feed to all other units.

(Reporting by Erwin Seba; editing by G Crosse, Bernard Orr)