Look here for next energy sector merger: Analyst

Spotting the next big energy sector merger could be tougher than investors expect, Henderson Global Investors' head of global equities said on Thursday.

Royal Dutch Shell's planned $70 billion takeover of BG Group has sparked speculation of a buyout boom in the energy patch. But Matthew Beesley sees the deal less as a sign of things to come than a special situation that brought together a willing buyer and seller.

"I don't think this necessarily means we're about to have a wave of M&A sweeping across the energy sector," he told CNBC's "Squawk on the Street."

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A repeat of the energy sector consolidation among oil majors is unlikely, he said. While ExxonMobil has a strong balance sheet and desire to enter new areas, BP is still dealing with the financial ramifications of a massive oil spill in the Gulf of Mexico and problematic assets in an increasingly isolated Russia.

Majors would also struggle to find targets in the North American exploration and production sector ripe for cost cutting because the drillers outsource much of their operations to oilfield services firms, he added. These organizations might not be willing to sell their assets during what they see as the lows of the current commodity cycle.

Beesley said he would keep his eye on potential acquistions that would allow energy firms to do a deal without issuing lots of equity or, in the case of the majors, prohibiting them from continuing dividend policies.

Shell's BG deal was about the biggest transaction it could do without impairing its credit rating and interrupting the dividend issuance it promised shareholders, he said.

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In the U.S. oil and gas sector, companies that have recently undergone management changes, are shifting around assets, or would benefit from a change in strategy could be targets, Beasley said. He pointed to Apache Corp. and Anadarko Petroleum as two names to watch.

Part of the problem is that deals today are difficult to assess because of commodity price uncertainty in the medium term. Beasley noted that some sell side analysts are building models based on oil rebounding to $80 in two or three years, while the futures market is still pricing crude at $60 to $65 over that time horizon.

"I think it's very hard for us to judge the merits, even the strategic merits, of these deals today when the financial returns of these deals is so uncertain and, indeed, so dependent on where the oil price ends up two or three years hence," he said.