* Harvey brings heavy rainfall, flooding to U.S. Gulf Coast
* Rebels attack oil pipeline in Colombia
* Operations in Libya still affected by pipeline blockade
* WTI discount to Brent hits two-year high
* North Atlantic storms history: http://tmsnrt.rs/2gcckz5 (Updates prices)
LONDON, Aug 29 (Reuters) - Crude prices dipped on Tuesday as the market grappled with the shutdown of some 13 percent of refining capacity in the United States after a hurricane ripped through the heart of the country's oil industry.
The refinery closures helped push U.S. gasoline futures to a two-year high of $1.7799 per gallon on Monday, although they had receded to $1.7030 by 1158 GMT on Tuesday.
International Brent crude futures were 32 cents lower at $51.57 per barrel, having traded as high as $52.19 earlier in the day.
U.S. West Texas Intermediate (WTI) crude edged down 5 cents to $46.52 a barrel, after falling more than 2 percent in the previous session.
The damage assessment could lead to more volatility. Some refineries were preparing for restarts, but heavy rains are expected to last through Wednesday, adding to catastrophic flooding in Houston.
"Refineries in Asia should run much harder to make up for (U.S. closures), which is supportive for Brent," said Olivier Jakob, managing director of oil analysis firm PetroMatrix.
Still, Jakob warned that the scale of U.S. upstream outages was not yet clear, and extensive damage on oilfields or pipelines could boost WTI prices.
Tropical Storm Harvey, which has been downgraded from a hurricane, hit oil refiners harder than crude producers.
"Around 2-3 million bpd (barrels per day) of refining capacity is offline or in the process of shutting down ... (and) more than 500,000 bpd of oil production... is offline," Barclays bank said.
It added that the storm's impact would "linger for several more weeks."
As a result, the discount of U.S. WTI versus Brent surpassed $5 per barrel, its widest in more than two years. <CL-LCO1=R>
Crude markets were also looking at disruptions in Libya and Colombia.
In Libya, militia pipeline blockades closed three oilfields and forced state-run National Oil Corp to declare force majeure at several sites. The 280,000-bpd Sharara field, the OPEC member's largest, has been shut for around a week.
In Colombia, a bomb attack by the leftist ELN rebel group halted pumping operations along the country's second-largest oil pipeline, the 210,000-bpd Cano-Limon Covenas.
Despite this, crude remains in ample supply, resulting in low prices.
"We are thus lowering our Brent oil price estimates to $55 per barrel from $60 per barrel in 4Q17 (and) to $57 per barrel from $64 per barrel in 2018," Jefferies bank said.
(Additional reporting by Henning Gloystein in Singapore; Editing by Dale Hudson)