On the New York Mercantile Exchange, light sweet crude futures for delivery in June settled at USD104.08 a barrel by close of trade on Friday, gaining 1.19% over the week.
Meanwhile, crude for delivery in May rose 0.8% to settle at USD103.05 a barrel. The contract expired at the end of floor trading Friday.
Market sentiment improved after the Group of 20 leading economies agreed Friday to boost the IMF's lending capacity by USD430 billion, to help shield the global economy from the debt crisis roiling the euro zone.
Also adding to the upbeat trade environment, the Ifo Institute for Economic Research said its index of German business climate ticked up to 109.9 in April, from 109.8 in the preceding month, against expectations for a decline to 109.5.
The news prompted investors to move in to riskier assets, such as stocks and industrial commodities, and shun traditional safe haven assets like the U.S. dollar.
The euro jumped to a two-and-a-half-week high against the greenback, while the dollar index, which tracks the performance of the greenback versus a basket of six other major currencies, declined 0.53% on Friday to end the week at 79.28, the lowest since April 3.
Oil prices typically strengthen when the U.S. currency weakens as the dollar-priced commodity becomes cheaper for holders of other currencies.
Meanwhile, market participants continued to monitor ongoing tension between Iran and the West and a potential disruption to oil supplies from the Islamic Republic.
Iran's crude exports declined to 2.1 million barrels per day, compared with a daily average of 2.3 million in the last Iranian year that ended on March 19, Iranian oil officials said in a report on Friday.
A potential loss of Iranian oil supplies has helped underpin strong gains in oil prices this year and prices could potentially go higher when a European Union embargo on Iranian oil imports goes into effect on July 1.
Oil futures fell to as low as USD102.12 a barrel on April 19, as Spain's borrowing costs rose above 6% amid fears that the government will struggle to reduce one of the largest deficits in the euro zone, in the face of a looming recession.
There have been renewed concerns of further debt contagion in the euro zone in recent weeks amid fears Spain will be the next in the euro zone to require a bailout.
The euro zone accounted for nearly 16% of global oil consumption last year, according to data from British Petroleum.
Also Thursday, data showed that manufacturing activity in the Philadelphia-region expanded at a slower rate than expected in April and U.S. existing home sales declined unexpectedly last month.
The data came after a government report showing that the number of people who filed for unemployment assistance in the U.S. last week fell less-than-expected, while the previous week's figure was revised higher.
The Department of Labor said the number of individuals filing for initial jobless benefits in the week ending April 14 fell by 2,000 to a seasonally adjusted 386,000, disappointing expectations for a decline of 18,000 to 370,000.
The previous week's figure was revised up to 388,000 from 380,000.
Oil traders have been paying close attention to readings on U.S. employment levels and manufacturing figures because they offer insight into the economic health of the world's largest crude oil consumer.
The U.S. is the world's biggest oil-consuming country, responsible for almost 22% of global oil demand.
Elsewhere, on the ICE Futures Exchange, Brent oil futures for June delivery settled at USD118.85 a barrel by close of trade on Friday. The Brent contract lost 1.35% over the week.
Brent prices dropped to as low as USD116.70 a barrel on April 18, the lowest since February 10.
Brent futures have been under pressure in recent weeks as the market is now balancing assurances from Saudi Arabia that it would make up for any supply shortfalls against the potential risk for the loss of oil from Iran.
Saudi Arabia and Iran are the two largest oil producers and exporters among OPEC members.
The spread between the Brent and the crude contracts stood at USD14.19 a barrel by close of trade Friday. The WTI-Brent spread dipped below USD14 per barrel earlier in the week, after hitting highs above USD20 in recent months.
The reduced spread between the two main global oil benchmarks came following news last week that owners of the Seaway pipeline slated to carry crude from Cushing, Oklahoma to the Gulf of Mexico had asked federal authorities to fast-forward the project by about two weeks.
Pipeline operators Enbridge and Enterprise Products Partners said they plan to switch the flow on Seaway about May 17, according to a filing with the Federal Energy Regulatory Commission.
The reversal is intended to ease the glut in U.S. crude stockpiles in the Midwest as the pipeline brings Canadian oil and North Dakota crude to the U.S. Gulf Coast.
In the week ahead, investors will be eyeing the Federal Reserve's rate statement for any signs that the central bank is leaning towards another round of monetary easing.
In addition, market sentiment looks set to remain dominated by concerns over Spain's fiscal woes, as well as Sunday's first-round presidential vote in France.
President Nicolas Sarkozy and Socialist challenger Fran?ois Hollande are expected to move to a head-to-head runoff on May 6. Most French opinion polls show Hollande would prevail in that runoff.
Meanwhile, Italy is due to auction 10-year government bonds on Thursday. The amount to be offered is to be announced on Monday.
Oil traders will also continue to monitor tensions between Iran and the West and a potential disruption to oil supplies from the region.