Shell's Deer Park, Texas crude unit shut up to 2 weeks -sources

(Adds details about units shut, Thursday fire, background on refinery)

HOUSTON, Aug 18 (Reuters) - The large crude distillation unit at Royal Dutch Shell Plc (LSE: 0LN9.L - news) 's 325,700 barrel per day (bpd) joint-venture Deer Park, Texas, refinery may be shut for up to two weeks of repairs from a Thursday fire, sources familiar with plant operations said on Friday.

"Operations are stable at Shell Deer Park," company spokesman Ray Fisher said.

The refinery's gasoline-producing fluidic catalytic cracking unit and hydrocracker are out of production due to loss of feed from the shut CDU, the sources said. The coker unit is near shutdown.

Production has been reduced on the olefins unit in the adjoining Shell Chemical Plant, the sources said. That unit is due to begin an overhaul in September.

The fire began when leaks developed around flanges on the 115,000 bpd VF-3 vacuum distillation unit connected to the 270,000 bpd DU-2 CDU, which is the larger of two at the Deer Park refinery, the sources said.

Residue released from the flange leaks then ignited on Thursday, according to the sources.

The CDUs do the initial refining of crude oil and provide feedstock to all other production units at the refinery. They operate at atmospheric pressure.

After shutting DU-2 and VF-3 because of the fire, Shell (LSE: RDSB.L - news) cut production on units downstream from the CDU.

By Friday, the 70,000 bpd FCCU was shut as were the 41,100 bpd gasoline hydrotreater and the 72,000 bpd reformer feed hydrotreater, according to the sources.

Production on the 67,000 bpd hydrocracker was stopped with the unit being kept at operating temperature as of Friday afternoon, the sources said.

The 92,000 bpd coker was operating at a very low production level, the sources said.

The refinery's sulfur recovery units were also shut down, according to the sources. Other units were also idled.

The refinery supplies feedstocks to the chemical plant.

Vacuum distillation units increase the yield from a barrel of oil by refining at vacuum pressure residual crude produced by CDUs.

Hydrocrackers produce motor fuels by refining gas oil under high heat and pressure in the presence of hydrogen and a catalyst.

Cokers further refine residual crude, increasing the yield of refinable material or converting it to petroleum coke, which can be used as a coal substitute.

Hydrotreaters remove sulfur from motor fuels to comply with U.S. regulations.

The Deer Park refinery is co-owned by Shell and Petroleos Mexicanos (Pemex), Mexico's national oil company.

(Reporting by Erwin Seba; Editing by James Dalgleish and Leslie Adler)