Shares in BP are rallying, helping lift the oil and gas sector higher.The oil giant said the cost of the clean-up in the Gulf of Mexico has risen to $3.5bn from $3.12bn a week ago and $2.65bn at the end of June, although some say that figure could eventually hit $70bn. The first half of August remains the current estimate of the most likely date by which the first relief well will be completed and kill operations performed, the company said.It is press coverage suggesting both Exxon Mobil and Chevron have received White House approval to launch a bid for BP that has got the market excited. Other press reports suggest the beleaguered UK oil giant is in talks with US independent oil company Apache over the sale of some of BP's assets in a deal that could raise up to $12bn.Underwater robots have started work on a new containment cap on the broken well in the Gulf of Mexico.Among smaller companies in the sector, Max Petroleum is in demand after it reported a recent study by Ryder Scott on the Kazakhstan-focused group's Blocks A&E licence areas showed total risked mean recoverable resources estimated at 1,100 million barrels of oil equivalent.But Falkland Oil and Gas (FOGL) lost almost two-thirds of its value after the Toroa F61/5-1 exploration well in the East Falkland basin turned up dry.Weak metals prices have miners on the back foot. Copper, lead, aluminium and nickel are lower as are the precious metals gold, silver and platinum.Among today's fallers is Rio Tinto. The mining giant is in the news today having referred Canadian miner Ivanhoe's breaches of a private placement agreement to arbitration following its adoption of the shareholders rights plan.Among smaller companies though, shares in Ariana Resources rallied after the Turkey-focused gold miner announced the completion of its joint venture agreement with Proccea to develop the Red Rabbit Project in western Turkey.Top performing sectors so far todayOil & Gas Producers 6,839.42 +2.04%Construction & Materials 3,131.88 +1.35%Oil Equipment, Services & Distribution 18,001.14 +0.91%Beverages 8,535.39 +0.81%Technology Hardware & Equipment 475.91 +0.76%Bottom performing sectors so far todayAlternative Energy 4,587.04 -1.71%Fixed Line Telecommunications 1,977.11 -1.01%Forestry & Paper 4,354.86 -1.00%Personal Goods 13,612.39 -0.91%Mining 19,861.94 -0.79%