“The flexibility to rapidly dial back investment in unconventionals at low prices has provided a competitive advantage for the US independents with the bigger positions,” according to a recent study. “Majors and international players lack exposure to this flexible investment.”

Oilfield service suppliers that provide equipment like drilling rigs will be among those hardest hit. Consequently, the oil services-sector ETFs may likely be among the worst performers in energy-sector during a low oil environment. For instance, IEZ includes a 78.4% tilt toward oil, gas equipment and services sector, along with 20.0% oil and gas drilling.

Order books for services have experienced a “steep decline” from the fourth quarter of 2014, with the backlog of business now running to two or three quarters.

For those seeking a hedge against further weakness in the energy sector, the ProShares Short Oil & Gas (NYSEArca: DDG) tries to reflect the inverse, or -100%, daily performance of the Dow Jones U.S. Oil & Gas Index. The UltraShort Oil & Gas ProShares (NYSEArca: DUG) takes two times the inverse, or -200%, daily performance of the Dow Jones U.S. Oil & Gas Index. The Direxion Daily Energy Bear 3X Shares (NYSEArca: ERY) reflects three times the inverse, or -300%, daily performance of the energy select sector index. Moreover, the recently launched Direxion Daily S&P Oil & Gas Exploration & Production Bear Shares (NYSEArca: DRIP) takes the -3x, or -300%, daily performance of the S&P Oil & Gas Exploration & Production Select Industry Index. [New ETFs for the Bold Energy Investor]

For more information on the oil industry, visit our energy category.

Max Chen contributed to this article.