Shell is among the stocks lifting the oil and gas sector higher. Chinese oil giants Sinopec and China National Offshore Oil Corporation (CNOOC) are thought to be readying bids worth about £3bn for the firm's assets in Nigeria.Elsewhere in the sector, Cairn Energy, which has secured a drill ship to get an early start on its exploration activities in Greenland, is another riser.The Stena Forth, a sixth generation dynamically positioned drill ship, has been contracted by the oil company to start operations in the summer of 2010 on Cairn's Disko West acreage in Greenland.Pharmaceuticals are slightly lower. Eco Animal Health is the heaviest faller in the sector after saying it raised £6m through the placing of about 4.25m shares at 140p a time.Top performing sectors so far todayBanks 4,628.84 +1.75%Oil & Gas Producers 7,981.01 +1.74%Automobiles & Parts 2,681.76 +1.59%Life Insurance 3,741.53 +1.23%Electricity 6,449.11 +0.96%Bottom performing sectors so far todayIndustrial Transportation 1,895.47 -1.66%Beverages 8,030.25 -0.12%Pharmaceuticals & Biotechnology 8,699.87 -0.11%Personal Goods 10,245.30 -0.05%Chemicals 4,396.56 -0.03%