Oil prices finished their best month in a year on Friday and are headed back toward $50 a barrel, bringing some relief to beleaguered energy producers even though they reported some of their worst quarterly results in years. Benchmark U.S. oil futures rose 20% in April, despite a slight slip Friday, and have surged 75% since bottoming out in February at a 13-year low. The rally has been more powerful than most analysts and investors anticipated. Declining U.S. production, corporate cost-cutting and production outages around the world have raised hopes that the crude-oil glut might be easing. So far this year, Exxon shares have risen 13%. Energy stocks in the S&P 500 are up nearly 9% in the past month alone. BP BP 0.27 % PLC shares rose Tuesday after it reported results that […]