The sharp decline in oil prices in the past year has put a damper on many big energy producers’ prospects, but that hasn’t kept them from joining the gusher of mergers-and-acquisitions activity. There have been $323 billion in announced or proposed oil-and-gas mergers so far this year, the most on record for a similar period by nearly $100 billion, according to Dealogic. Oil and gas is the third-most-active sector for M&A this year and has helped drive overall announced deal volume to $3.2 trillion world-wide, putting 2015 on pace to roughly match the record of $4.3 trillion set in 2007. “The big deals that we’ve seen have all had strategic merit, a consistent message from management and synergies that justify paying a premium,” said Dan Ward, co-head of Deutsche Bank AG DB 1.13 % ’s global natural-resources group. “They’ve been done by large, best-in-class, well-capitalized companies that can afford […]