A large share price decline at Cairn Energy meant that the oil and gas producing sector was at the bottom of the pile on Wednesday. Falling oil prices didn't help much as Brent Crude futures were nearly 2% lower at $114.16 at 16:22.Oil exploration group Cairn Energy said that despite the inital promising analysis in the South Ungavva area (offshore Greenland), the LF7-1 exploration well has not met its target. The FTSE 100 stock was trading 5.22% lower at 334.30p in the afternoon.Meanwhile, the mobile telecommunications sector was making gains, driven by Avanti Communications.The satellite broadband firm rose higher after extending its contract with Hughes Network Systems. Avanti said that Hughes had fully allocated its initial purchase £7.5m of capacity on its HYLAS 1 satellite to existing clients.Shares were 1.11% higher at 319.50.BCTop performing sectors so far todayElectricity 8,273.88 +1.41%Mobile Telecommunications 3,883.49 +1.12%Gas, Water & Multiutilities 4,617.82 +0.97%Alternative Energy null 0.00%Leisure Goods null 0.00%Bottom performing sectors so far todayOil & Gas Producers 7,999.79 -3.86%Pharmaceuticals & Biotechnology 9,120.89 -3.52%Technology Hardware & Equipment 691.48 -3.39%Electronic & Electrical Equipment 3,047.20 -3.25%Oil Equipment, Services & Distribution 23,071.64 -3.25%