ConocoPhillips is integrating new assets as it focuses on its best properties, setting up for stronger returns when oil prices rise again.If there is one thing that investors need to understand about the energy sector, it is that oil and natural gas prices are inherently volatile. But there's a somewhat counterintuitive takeaway here. Sometimes the best investment opportunities arise when business in the oil space isn't going so well.Which is why investors might want to buy ConocoPhillips (COP -2.67%) today ...