Oil and gas producers were flowing higher on Tuesday after a well-received first-quarter update from sector heavyweight BP.BP, the largest UK-listed stock in the sector with market capitalisation of £90bn, was trading at its highest level in two months after profits fell less than expected in the first three months of the year.Underlying profit was $3.23bn, down from $4.22bn a year ago but 4% ahead of consensus forecasts, somewhat flattered by a low average tax charge.Chief Executive Bob Dudley called the performance a "very solid start" to the year and pointed to strong operating cash flow, exploration success and upstream project start-ups, and the ramp-up of the upgraded Whiting refinery.Broker Investec kept a 'hold' stance on the stock today, but said that the update showed a "solid start to the year".The shares were 2.4% higher at 500.1p by 15:53; they have not closed above this mark since the end of February.Sector peer BG Group was also rising strongly today after analysts at HSBC, Deutsche Bank and Goldman Sachs all reiterated their positive ratings on the stock.The stock was clawing back some of yesterday's heavy losses which came after it delivered a double blow to investors, announcing the departure of Chief Executive Chris Finlayson and warning that its 2014 production levels would be at the lower end of expectations due to challenges in Egypt.Ophir Energy, Afren and Tullow were also higher.Top performing sectors so far todaySoftware & Computer Services 1,175.32 +2.44%Industrial Metals & Mining 1,193.31 +2.09%Oil & Gas Producers 8,390.32 +1.70%Life Insurance 7,059.74 +1.67%Industrial Transportation 3,060.73 +1.35%Bottom performing sectors so far todayTechnology Hardware & Equipment 1,094.05 -0.81%Electronic & Electrical Equipment 4,098.34 -0.43%Support Services 6,475.57 -0.31%Personal Goods 23,527.41 -0.15%Aerospace and Defence 4,739.86 -0.13%BC