It's been a dramatic week for stock markets but oil prices have remained range-bound, with the price of a barrel of WTI crude drifting between $95 and $97. In London, the story has been similar -- Brent crude started the week at around $114 per barrel and looks likely to finish at a very similar level, after bouncing off a high of $116.62 and a low of $112.55.

Natural gas prices have proved less robust, though, touching a high of $2.88/mmbtu early in the week, before drifting down to around $2.68/mmbtu on Friday morning. All of this means investors in the United States Oil Fund (NYSE: USO) have little to smile about this week, with their fund losing 1.9% over the week to Friday morning, while the United States Natural Gas Fund (NYSE: USG) has slipped by 1.2% during the same period.

Oil prices have been high for much of this year, but some junior oil and gas shares have managed to outperform the market by a big margin, highlighting the potential benefits of investing in companies, rather than commodities. Here are three of the top climbers of late:

FX Energy (Nasdaq: FXEN) has gained 48% in the last twelve weeks, rising to $7.48 as it makes solid progress drilling and production testing its wells in Poland's Permian Basin -- an area believed to have substantial gas resources. Gas prices are much higher in Europe than in the U.S., making the area a very commercial prospect for the company.

Gulf Keystone Petroleum (LSE: GKP.L) has gained 14% to 234 pence in the last week. The company -- a favorite with U.K. private investors -- has always had a volatile share price, but the recent entry into Kurdistan of several oil supermajors has boosted confidence that a route to commercial exploitation and export will be found for Gulf Keystone's sizable oil resources.

Circle Oil (LSE: COP.L) has risen 17% to 21 pence over the last month after confirming it has drilled two new producing wells in Egypt and achieved a 53% increase in pre-tax profits over the last six months compared to the same period last year. So far this year, Circle has also commissioned a new pipeline in Morocco and doubled its gas sales to 4.4MMscf/d.

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