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.

Enterprise Products Partners (EPD 0.45%) reports earnings on Thursday. The midstream company has been pretty busy over the past few months and there should be plenty of material to pour over in the third-quarter release. Here are three things to watch for when Enterprise reports.

1. NGL prices
Enterprise has a strong fee-based business model, but it is not immune from the effects of depressed commodity prices. Ethane and propane are two particularly weak components of the natural gas stream right now, and we may see the effect of that on revenue. In fact, while analysts expect propane prices to recover by 2013, the outlook is not that great for ethane. Look for management to address this concern in the conference call.

2. Distributable cash flow and coverage
Enterprise has a strong history of increasing its distributable cash flow and distribution payouts. While investors probably don't need to worry about this trend continuing -- the partnership has already increased its third-quarter distribution -- it should absolutely be tracked from quarter to quarter. Last quarter, Enterprise reported distributable cash flow of $876 million, good for 1.6 times distribution coverage.

The third-quarter distribution will be $0.65 per unit, up 6.1% from 2011's third-quarter payout.

3. Forward progress
Enterprise has some $8 billion of projects in the works right now, $3 billion of which should be completed by the end of this year. Anytime a company is that busy, it's important to keep an eye on how often the phrase "on time and under budget" comes up. In Enterprise's case, most of these new projects are "fee-based", the type of business the partnership expects to derive 80% of its gross margin from by next year, so keep an eye out for that phrase as well.

Foolish bottom line
Analysts are expecting earnings of about $0.60 per unit, while revenue estimates range from a high of $13.14 billion to a low of $9.84 billion. Last quarter analysts anticipated earnings per unit of $0.58, but actual earnings came in higher at $0.64. Enterprise reports before the market opens on Thursday, with its conference call scheduled for 10:00 a.m. EST that morning. Interested investors can listen here, or click here to add Enterprise Products Partners to My Watchlist.