Crude-oil futures finished a week of wild swings with a gain on Friday, with the U.S. benchmark posting its fourth consecutive weekly advance as fears a nuclear deal with Iran could result in a near-term flood of crude exports faded. Oil futures briefly edged to session highs after oil-services firm Baker Hughes reported another weekly drop in the number of U.S. oil rigs.

On the New York Mercantile Exchange, light, sweet crude futures for delivery in May rose 85 cents, or 1.7%, to close at $51.64 a barrel. The U.S. benchmark saw a 5.1% weekly rise, and that is after a 6% plunge on Wednesday inspired by another sharp increase in U.S. inventories. May Brent crude on London’s ICE Futures exchange rose $1.30, or 2.3%, to close at $57.87 a barrel, marking a 5.3% weekly rise.

Oil previously saw pressure on fears an eventual deal to curb Iran’s nuclear program would result in a surge in crude exports as sanctions against Iran are eased. But some analysts argued that such fears were overblown. “Even if a final deal is reached, Iran is unlikely to be able to significantly ramp up its exports until 2015 at the earliest,” said economists at Capital Economics. Oil had gained ground Thursday after Iran’s supreme leader Ayatollah Ali Khamenei said the U.S. and its negotiating partners must lift all sanctions on his country immediately after a final deal to curb Iran’s nuclear program is signed. His comments were bullish in particular for Brent crude, the Middle East benchmark, as they introduce an additional political hurdle to completing a nuclear deal by June, a deal that has the potential to add 800,000 barrels a day of Iranian crude to the oversupplied global market, analyst Tim Evans at Citi Futures said in a report.

A slower return to the export market by Iran is seen as a positive by traders, but the timing of an agreement could still interfere with a recovery in prices, wrote analysts at KBC Bank in Brussels. “The timing is interesting as the increase could come precisely when the low oil prices should start to have a greater impact on the production-growth rate in the U.S.,” they said. “In other words, the anticipated decline in oil production by the U.S. may be (more than) offset by increased exports from Iran. Thus the period of low oil prices may become longer.”

Rig count falls: Baker Hughes said the number of U.S. oil rigs fell by 42 to a total of 760 in the latest weeks, while total rigs were down 40 to 988. The number of rigs has fallen sharply in reaction to a more-than-50% plunge in oil prices since mid-2014, but production has remained strong. Since this time last year, the number of oil rigs has declined by 757, according to Baker Hughes.

Next week, the International Energy Agency and the Organization of the Petroleum Exporting Countries will publish their monthly assessment of oil markets.