* Oil spillage from cracked pipelines; none from tanker
* Tanker suspected to have approached at higher thanrecommended speed
* Cleanup for seashore seen to take up to two weeks
* No refinery production impact from the incident
* Ocean Tankers says to discuss with Shell over unloading
By Meeyoung Cho and Keith Wallis
SEOUL/SINGAPORE, Feb 3 (Reuters) - Teams of workers, aidedby ships and aircraft, will complete on Monday the sea cleanupof 164,000 litres of oil that leaked off South Korea's southerncoast, the coast guard said, after a pipeline run by GS CaltexCorp cracked at the weekend.
A cleanup of shore areas will take up to two weeks.
The crack and subsequent leak occurred on Friday at a quayoff Yeosu, more than 300 km (185 miles) south of Seoul, whilethe 318,445 deadweight tonne Very Large Crude Carrier Wu Yi Sanwas preparing to berth and offload crude.
Oil remaining in the pipeline leaked, but none spilled fromthe tanker, which did not hit refinery production at GS Caltex,according to the refiner and the Korea Coast guard.
"A clean up would be completed within today, while a cleanup of the seashore would take one or two weeks," a seniorofficial at the Yeosu Coast Guard of Korea told a press briefingbroadcast live on television.
The prime minister's office, in a statement issued on Sunday, said an oil boom to control the spillage would beexpanded to a diameter of 9.5 km from 5 km, and 201 vessels andfive planes would work on the clean up.
The coast guard official said the tanker was suspected ofapproaching the quay at a higher than recommended speed, but theexact cause of the accident was under investigation.
He added that crude oil, naphtha and other oil compoundsleaked from three cracked pipelines at the quay.
The tanker is operated and managed by Singapore's OceanTankers, which said the vessel was under the control of two portpilots and assisted by five harbour tugs when it struck theshore jetty and pipeline.
Surveyors from ship safety classification society ABS andthe ship's insurer, the North of England P&I Association, arehelping the investigation and assessing damage to the ship, saidNg Kwang Chiau, senior vice president at Ocean Tankers' fleetmanagement division.
He said the ship's voyage data recorder, or "black box",would be analysed as part of the investigation.
NO SPILL FROM SHIP
There were no injuries to the crew, Ng said. The front ofthe ship sustained minor damage, but the vessel was safelyanchored.
The ship was chartered to Shell, Ng said and talkswould take place with the oil major about unloading options, hetold Reuters.
A spokesman at GS Caltex said: "The tanker needs to gothrough safety tests before unloading the crude and unloadingmight be done through a jetty nearby or ship-to-ship, which theshipper is in charge of."
He declined to comment on the type of the crude in thetanker.
South Korea's second-largest refiner, with a775,000-barrels-per-day (bpd) capacity, GS Caltex is equallyowned by Chevron Corp, the second-largest U.S. oilcompany, and South Korea's GS Energy, owned by GS Holdings.
In 2007, South Korea's worst oil spill occurred off thecoast of Taean, when 10,500 metric tonnes spilled from a HongKong-registered tanker whose hull was punctured in a collision.
In November 2013, a small amount of oil leaked into the seaeast of South Korea from a cracked pipeline run by the country'stop refiner, SK Energy, owned by SK Innovation.