Oil prices rose on Tuesday, after sliding by around 15 percent so far in May, but investors were concerned about global growth prospects after a slew of weak economic data.

ICE Brent for July was up 40 cents at $111.24 by 1258 GMT. U.S. crude futures for June delivery rose 11 cents to $97.48 a barrel on the day of the front-month expiry.

The market continues to consolidate after recent volatility. This is a bottom for the short-term, said Andrey Kryuchenkov of VTB Capital, adding that the risk premium for further supply disruptions in the Middle East has now been almost wiped out, limiting scope for further falls.

The war in Libya has nearly halted its oil exports but political unrest has not led to supply disruptions in other OPEC member states.

Trading volumes on U.S. crude have fallen so far this week in a move that some analysts took as a sign of uncertainty about price direction, with liquidity less than half the multi-year highs hit in the immediate aftermath of the crash in early May.

U.S. oil prices are set for their biggest monthly price drop since January 2009 and have been volatile since falling 10 percent in a single session. Daily volatility based on data from one market close to the next has flattened in the last couple of sessions but is still near 25-month highs, Reuters data showed.

U.S. crude inventories likely rose for the fourth straight week as higher imports outpaced refinery demand, a preliminary Reuters poll ahead of weekly industry and government reports showed on Monday.

Crude inventories were expected up 1 million barrels in the week to May 13 and gasoline stocks were seen up 1.1 million barrels. If confirmed, this could stoke a further sell-off in RBOB gasoline futures after a 5 percent slide on Monday within days of the start to the U.S. peak summer driving season.

Traders watched for a further rise in inventories at the U.S. delivery point of Cushing, Oklahoma, which hovered just below record highs.

Fears that rising water levels on the Mississippi River would affect eight refineries in Louisiana have abated following news the U.S. Army Corps of Engineers began opening flood gates.

OPEC producer Libya's top oil official Shokri Ghanem, chairman of Libya's National Oil Corporation has defected from the government of Muammar Gaddafi, the rebels' finance and oil minister said on Tuesday.

He left Libya for Tunisia, a rebel source told Reuters.

(Additional reporting by Florence Tan in Singapore; Editing by William Hardy)