BP (NYSE: BP) on Tuesday reported stronger-than-expected earnings for the third quarter as higher output, field start-ups, and improved refining margins offset weaker oil prices and trading result. BP booked an underlying replacement cost profit – the closest metric to net profit – of $2.21 billion for the third quarter, essentially flat on the year, but surpassing an average consensus estimate of $2 billion. The UK-based supermajor cited higher profitability in the operating segments, increased refining margins and utilization…