Updated from 11:31 a.m. ESTOil eased Friday as bullish traders tried to defend the $60-a-barrel level after a 5% selloff this week. April crude settled down 52 cents at $59.95 a barrel, after rising 43 cents on Thursday. The price has been bobbing around a the $60 mark after posting consecutive declines on the first three days of the week. Bearish inventory reports, OPEC's decision not to cut production and an easing of tension around Iran's nuclear program helped spur the decline. Gasoline, which rallied Thursday as traders anticipated early spring driving weather, fell 3 cents to to $1.68 a gallon. Heating oil fell 3 cents to $1.69 a gallon, and natural gas gained 5 cents to $6.65 per million British thermal units. The major geopolitical news Friday was a report of a militant attack on a tanker in Nigeria. Rebel activity in the North African country has cut about 20% of its daily crude output over the last month or so. Energy shares were mixed. In recent trading, the Philadelphia Stock Exchange Oil Services index was up 0.6%, while the Amex Oil index rose 0.4%. Shares of Exxon Mobil ( XOM) and BP ( BP) were both down 0.2%, while Valero ( VLO) was unchanged and Halliburton ( HAL) rose 1.4%.