There are a few oil service companies that have really done well lately.
If you study their chart patterns they basically look the same. This means most all the mutual funds and hedge funds are investing in them. Look at the OIX. Then look at NTG, SLB, HAL, and NBR. They all have a bright future.
Back in the 1970's oil companies kept giving these companies more work to explore for more oil. Rigs and support to the oil industry. They will always be in demand and will make a good profit. Look at the above companies and buy the ones you are able to be a piece with. Hold for at least 3 years because they will double in price by then.