"The global supply picture is extremely bullish for crude oil," says energy expert Elliott Gue, who is playing this trend through oil services, equipment, and exploration firms including Schlumberger (NYSE: SLB), which he calls the "world's premier oil services play."

The editor of The Energy Strategist explains, "OPEC's current oil output isn't high enough to allow global oil importers to build their crude stocks ahead of the summer driving season. The fundamentals of strong growth in demand, coupled with static to falling supplies, are supporting higher global oil prices."

Further, he notes that unrest and weak output from Nigeria, terrorist attacks in Algeria and tension in the Middle East, and there are additional of reasons to be concerned that supplies could be cut even further from "current anemic levels."

All told, he sees, this as "a recipe for a significant rally in crude." In addition, he notes that global activity remains brisk, He notes, "We've seen no letup in the red-hot pace of international drilling and exploration activity; I expect no such slowdown to develop. In fact, if anything, the current environment should accelerate global oilfield activity."

Oil services -- he explains -- is a "catch-all term" used to describe a wide variety of oil production and exploration-related functions. He notes, "Suffice it to say that producers -- firms such as ExxonMobil (NYSE: XOM) and Chevron (NYSE: CVX) -- need oil and gas services firms to find and produce hydrocarbons.