Let's head back momentarily to a time precisely five years ago. Crude prices were headed for their all-time highs near $150 a barrel, and Warren Buffett was ambidextrously reaching for all the ConocoPhillips shares he could get his hands on.

It was, he later admitted, a major mistake. But who knew? The seers at Goldman Sachs were convinced that black gold was ineluctably headed for $200 a barrel. As a consequence, shares in the then-integrated Conoco -- which has since reinvented itself as the world's largest independent producer -- like those of most other oil and gas operators, seemed like a grand bargain. That is, until crude prices turned tail and plummeted to the $30s during the next six months.

The market's speed bumps
Today, we have crude oil in earshot of $100 a barrel and, as I see it, at least three key phenomena capable of affecting substantially both oil levies and the markets, in general. First, there's the obvious anxiety about the Federal Reserve's timing for weaning us, and our economy, from our addiction to monetary stimuli. Next, the conflagration in Syria is likely far more potentially world-altering than is generally recognized. And third, the implementation of Obamacare will probably wound key aspects of our economy.

We'll see
Almost certainly Obamacare will have a deleterious effect on the nation's unemployment rate, as companies furlough some employees, and switch others to part-time status. But then, even the Fed apparently is unaware of the program's dicey specter, since its prediction for unemployment in 2014 has just been lowered to a 6.5% to 6.8% range, from the earlier 6.7% to 7%. Lots of luck.

All of these considerations are coalescing to signal loudly that we're dealing with an equities market that's best treated with kid gloves. One way of doing so, it seems to me, is to hold at least a modicum of solid energy names. While there are lots of compelling companies in the sector, let me point to a few that I believe can provide a combination of stability and upside potential.

Schlumberger (NYSE:SLB) is easily the most brightly shining example of a company whose attraction is based, at least in part, on a hard-to-beat combination of geographic scope and technological leadership. With a "crew" of about 120,000 plying their trade in about 85 countries, the company serves the entirety of the worldwide petroleum industry, including national oil companies, integrated majors, and independent producers.

Technology, where Schlumberger is the industry's clear-cut leader, has become progressively more vital to the global quest for oil and gas. The company fully operates 25 worldwide research and development facilities, into which it pours nearly $1.2 billion annually.

Similarly, while Chevron (NYSE:CVX), is the only major producer working upstream in Saudi Arabia, it's also a leader in the Gulf of Mexico, South America, West Africa, the South China Sea, Canada, and the United Kingdom. Less recognized are its successes in developing renewable energy, including the development and operations of several successful solar projects.

In addition, Chevron is the analysts' most highly rated integrated company, and easily possesses the group's most muscular balance sheet.

National Oilwell Varco (NYSE:NOV), a favorite among Fools, has somewhat quietly catapulted itself into a $30 billion (market capitalization) company. Concurrently, it's become the leading manufacturer of much of the key equipment and many of the components used worldwide in oil and gas exploration and production.

Varco's somewhat disappointing first quarter was largely attributable to the need for digestion of the 51 acquisitions it's consumed during the past four years. Nevertheless, the company retains a solid consensus buy rating by the analysts who follow it.

Denbury Resources (NYSE:DNR) presents a compelling niche opportunity for Foolish energy investors. The company's focus is on carbon dioxide-based enhanced oil recovery (CO2 EOR). The process involves the injection of CO2 under high pressure into generally tired, old wells, thereby coaxing out much of the remaining hard-to-get-to oil.

Unless you're a believer that our planet's supply of oil is infinite, Denbury clearly bears watching. The Plano, Texas-based company achieved operating margins near 43% and is essentially debt free.

Fool contributor David Smith owns shares of Denbury Resources. The Motley Fool recommends Chevron and National Oilwell Varco. The Motley Fool owns shares of Denbury Resources and National Oilwell Varco. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.