Sector movers: Energy stocks tank as oil prices continue to tumble

Another tumble in the price of oil knocked stocks in the energy sector on Monday with investors concerned that the continued decline in crude prices will continue, while producer Afren lost over a quarter of its value after a disappointing project update.Brent crude was down 4.7% at $47.75 a barrel, trading at its lowest in over five and a half years, after analysts lowered their forecasts for prices.Oil had sunk 50% over the course of 2014 following an OPEC decision not to cut production despite the current supply gut, with US output rising to its highest in over 30 years. Prices are now at their lowest since April 2009.Providing further downwards pressure on the commodity were gloomy comments from Saudi billionaire Prince Alwaleed bin Talal who said that $100-a-barrel oil is a thing of the past."If some supply is taken off the market, and there's some growth in demand, prices may go up. But I'm sure we're never going to see $100 anymore," he said.Afren was a standout faller in the sector, trading 27% lower at 28.8p after reporting "material reduction" in reserve estimates at its Barda Rash field and saying it is now looking at its "strategic options" for its 60% stake.Further analysis of the Kurdistan project has meant that reservoirs have "not performance according to previous expectations and the approved field development plan".Afren was also hit by a ratings downgrade by Canaccord Genuity from 'buy' to 'hold', while analysts at Goldman Sachs and Deutsche Bank lowered their target prices for the stock.BG Group, Shell, Premier Oil, BP, Ophir Energy, Tullow Oil and Genel Energy were all registering with heavy losses in afternoon trade, tracking the price of crude lower.Top performing sectors so far todayAutomobiles & Parts 8,040.61 +1.81%Technology Hardware & Equipment 1,188.07 +1.53%Forestry & Paper 11,396.10 +0.86%Travel & Leisure 8,024.59 +0.83%Personal Goods 24,839.19 +0.81%Bottom performing sectors so far todayElectricity 8,962.06 -5.42%Oil Equipment, Services & Distribution 14,708.58 -5.01%Oil & Gas Producers 6,752.98 -2.38%Mining 13,761.37 -2.24%Industrial Metals & Mining 1,450.72 -1.93%