The decision to buy Copano Energy LLC (Nasdaq: CPNO) for about $4.9 billion will likely give the shares of the buyer, Kinder Morgan Energy Partner LP (NYSE: KMP), a mild boost, according to an independent analyst.

“The deal appears to offer a very slight accretion to KMP upon closing and is incrementally positive over the long-term,” according to a report from Raymond James & Associates Inc. The deal will also extend Kinder Morgan’s footprint in the active Eagle Ford shale.

Under the terms of the deal announced earlier this week, ...