They say an elephant never forgets, but just about anyone can recall two years ago when the likes of ExxonMobil (NYSE: XOM), Total (NYSE: TOT), and other crude oil producers benefited from escalating oil prices that ultimately topped out at almost $150 a barrel. With prices north of $86 per barrel, are we quickly heading back to the triple digits?

And while prices toppled rapidly after peaking, in May of last year oil was still trading above $65 a barrel. Yesterday, traders were buoyed by the U.S. Labor Department's relatively optimistic jobs report, which was released when many investors were celebrating Good Friday, and pushed oil prices to heights not seen in a year and a half.

So where do we go from here? Indeed, there are several factors that could move prices temporarily in either direction. For instance, a strengthening dollar could add downward pressure, as could an increase in production from the OPEC countries, most of which curtailed their output more than a year ago and have 6 million barrels per day of idle production in their back pocket. Also, recent crude discoveries by such majors as BP (NYSE: BP), Petrobras (NYSE: PBR), and Chevron (NYSE: CVX) ultimately could have an impact on lowering prices somewhat.

Factors raising prices would include a sustained global economic recovery, which seems to be the market consensus, along with stimulus spending in places like China, the U.S., and the European Union. In fact, some believe the latter likely has already pushed crude prices up to $15 above what they might otherwise be.

And then there's the role of natural gas prices. A number of the major companies are increasing their attention to this cleaner-burning hydrocarbon. Despite its longtime affinity for oil, Exxon is in the process of buying gas producer XTO (NYSE: XTO), while Shell (NYSE: RDS-A) will produce more gas than oil within the next couple of years.

Partially due to the explosion of unconventional discoveries, prices have fallen out of step with oil. If gas prices remain low enough, you could potentially see some switching, at least in the U.S., away from foreign oil and toward domestic gas. But that could change given a new Department of Energy realization that it may have been unknowingly overstating gas production.

For what it's worth, my opinion is that crude will enjoy solid price support in the vicinity of $85 per barrel, especially as driving season arrives. And as time goes on, that support level will increase slowly, as will prices. I therefore believe that Foolish portfolios that don't include oil and gas producers are incomplete. My favorites continue to be ExxonMobil and BP, but I'd love to hear your favorite plays for the sector in the comments box below.

Fool contributor David Lee Smith doesn't own shares in any of the companies mentioned above. He does welcome your question or comments. Petroleo Brasileiro and Total SA are Motley Fool Income Investor picks. The Fool owns shares of XTO Energy. Try any of our Foolish newsletters today, free for 30 days. The Fool has a disclosure policy.