UAE Oil Minister Suhail bin Mohammed Al Mazroui expects the oil price to pick up in the second half of this year, he said on Thursday.

Mazroui told reporters in Vienna the market needs the oil price to appreciate to sustain investment in the sector. Benchmark Brent crude was trading at just under $50 a barrel on Thursday.

Oil ministers from the Organization of the Petroleum Exporting Countries (Opec) are meeting in the Austrian capital.

In another developement, Venezuela's oil minister Eulogio del Pino proposed an "oil supply range" for individual Opec countries.

Del Pino added that such a range could substitute for talks on an output ceiling.

Venezuela's crude production stood at around 2.8 million barrels per day last month, he added.

Algerian Energy Minister Salah Khebri said he was optimistic that Opec will return to an oil output ceiling with production quotas for individual member countries.

Angolan Oil Minister Jose Botelho de Vasconcelos said he believed there was a possibility that he and his Opec counterparts could reach a decision on a possible ceiling on the group's crude output.

Botelho de Vasconcelos told reporters that an oil price of $60 was not bad, but "$80 would be better."

Several Opec sources said on Wednesday Saudi Arabia and its Gulf allies would propose to set a new collective ceiling in an attempt to repair Opec's waning importance and end a market-share battle that has sapped prices and cut investment.

Meanwhile, Iran pledged that it would boost the oil production to 4.8 million barrels per day within the next five years.

"Iran's oil production capacity will reach 4.8 million bpd in five years,"  the country's oil minister Bijan Zanganeh said on Thursday in Vienna before a meeting of Opec oil ministers.-Reuters