HOUSTON, Jan 19 (Reuters) - Pemex’s Deer Park, Texas refinery was operating on Friday at 80% of its 312,500 barrel-per-day (bpd) capacity, said people familiar with plant operations.

Pemex reduced production at the refinery prior to a winter storm’s passage across the Texas Gulf Coast on Monday, the sources said.

Reducing production gave refinery operators more flexibility in responding to problems that might develop in the cold weather that blanketed the area for the first part of the week, the sources said.

Production remains at the 80%-level because internal utilities have been unstable in colder weather, according to the sources.

Temperatures are expected to drop below freezing over the weekend.

Pemex is also preparing for an upcoming overhaul on the 70,000-bpd DU-1 crude distillation unit, according to the sources.

(Reporting by Erwin Seba Editing by Marguerita Choy)