Natural gas pipeline operator Atlas Pipeline Partners L.P. said Wednesday it has agreed to sell its Oklahoma-based Elk City gas gathering and processing system for $682 million in cash.

The sale to Enbridge Energy Partners L.P., Houston, will allow Atlas to pay down debt, resume distributions to unit holders and "participate in the sharp growth of its Marcellus Shale gathering venture," the company said in a written statement. The natural-gas-laden Marcellus, underlying a huge swath of Pennsylvania, has sparked a recent rush in gas drilling and production.

Atlas has headquarters near Pittsburgh, but some executive offices are in Philadelphia.

Its shares jumped $3.82, or 30.1 percent, to $16.17 in early afternoon trading. Enbridge shares were down 70 cents, to $56.90.    - Reid Kanaley