Summertime is almost here, and with oil prices spiking, the living looks easy for energy investors.

West Texas Intermediate spot futures, the benchmark for North American oil, have risen nearly 20% so far this year to above $70 per barrel. The recent crude rally has been so impressive, it is finally getting a rise out of oil stocks, pushing the exchange-traded funds that track them sky-high. They stand to gain even more if crude prices continue their relentless rise.