The energy sector is known for being volatile, given that oil and natural gas are commodities. But there's one niche in the energy sector that tends to be far less volatile -- the midstream. Yet all midstream companies are not created equal. The upstream segment of the energy sector is filled with companies that produce oil and natural gas. Given that the prices of these commodities can fluctuate wildly over time, the revenue that upstream companies bring in is highly volatile. It costs a lot to drill for o ...