U.S. domestic oil and gas production is higher than it's been in decades, and as a result, the midstream industry is booming as well. But headline hogs such as Kinder Morgan (KMI +4.21%) and TransCanada (TRP +3.47%) aren't doing all the work. In this video, energy analyst Aimee Duffy takes a look at Pembina Pipeline (PBA +3.96%) and Boardwalk Pipeline Partners (BWP +0.00%), two lower-profile midstream outfits that may be right for your portfolio.