Buckeye opened a 7.5 million offering of limited partnership units to partly fund the deal, which is expected to close in early January 2017, Reuters reported.
The combination of American Midstream and JP Energy provides scale and efficiency, companies say.
Rising natural gas prices lift NGL, especially ethane, to levels not seen since late 2014.
Tillerson said that shale oil producers' resilience in cutting costs to make some wells profitable at low oil prices means that North America has effectively become a swing producer.
Stratas Advisors expects coming winter demand and exports to prop up natural gas and NGL price recoveries as well as production.
Open Season For Shell’s Ethane Pipeline In Northeast
Expected lower temperatures than last winter will push up costs for households in the Midwest and Northeast, despite high natural gas storage levels.
Natural gas resurgence buoys NGL prices as ethane rides 34% rally in recent weeks.
The deal, the largest so-called "dropdown" from Phillips 66 to the unit, includes assets supporting the company's refineries in New Jersey, Montana, Texas and Oklahoma.
Best NGL “barrel” price in 17 months at Mont Belvieu is driven by rallies in ethane, isobutane and pentanes-plus.
Propane exports soared in the first half of 2016, but the price disadvantage in Asian markets have hindered shipments since.
NGL from the U.S. shale boom such as ethane, an alternative to naphtha refined from crude, could feed as much as a third of demand growth in 2017, BP's Richard de Caux told the Platts Refining Summit in Brussels.