Midstream companies have grabbed investor attention recently, and for good reason. Oil and gas production volumes have increased across America, resulting in a massive build-out of midstream infrastructure and a ton of acquisitions.

Energy Transfer Partners (ETP) and Energy Transfer Equity (ET 0.12%) report earnings on Wednesday, Nov. 7. The midstream companies have been pretty busy over the past few months and there should be plenty of material to pour over in the third-quarter releases for both the general partner and the master limited partnership. Here are three things to watch for when Energy Transfer reports.

1. Distributable income
Many expect Energy Transfer to begin to increase its distribution for the first time in over four years in 2013. In order for that to happen, ETP needs to continue to increase its distributable income. Last quarter the partnership reported an increase of $51.9 million. That number will likely garner an early mention in the earnings release and conference call; it is the figure on everyone's mind right now.

2. Sunoco assets
Energy Transfer Partners closed its acquisition of Sunoco in the first week of October, and while we may not see many effects of that deal on the balance sheet, we can hope to hear an update on the integration progress. Specifically, some sort of concrete plan for handling the 4,900 gas station and convenience stores that ETP picked up in the acquisition. Analysts expect ETP to sell the operation, perhaps for as much as $2 billion, but management has yet to comment definitively one way or the other.

3. NGL volumes
Energy Transfer suffered at the hands of low natural gas liquids pricing in the second quarter of this year. The situation hasn't improved since last quarter, though the price decline of NGLs has leveled off somewhat. Last quarter ETP was able to mitigate some of those losses by increasing NGL volumes on its system. We will have to wait to see how successful it was doing that again this quarter. On top of that, the partnership expects margins to improve as more fee-based projects come online. For comparison, non-fee-based contracts and processing margins for ETP's midstream segment were down 9% in the second quarter.

Foolish bottom line
Analysts are expecting earnings of about $0.30 per unit, while revenue estimates range from a high of $2.87 billion to a low of $1.22 billion. Last quarter analysts anticipated earnings per unit of $0.41, but actual earnings came in at $0.01. Energy Transfer reports after the market close on Wednesday, with its conference call scheduled for 9:30 a.m. EST the following morning. Interested investors can listen here, or click here to add Energy Transfer to My Watchlist.