From the Introduction: "The Strategic Petroleum Reserve (SPR), administered by the Department of Energy (DOE), has been a part of U.S. oil security policy for over 40 years. Originally intended as a reserve to replace oil that might be withdrawn from the world market to forward political purposes and objectives, its rationale has evolved with the changing world oil market and the role of the United States in the market. In addition to replacing oil lost to political turmoil, as in Libya in 2011, in recent years it has been more commonly used to replace oil supplies curtailed due to natural disasters, mainly hurricanes. The effects of hurricanes, especially those of the magnitude of Katrina, Rita, and others, has threatened to disrupt oil production, refining, and distribution, creating potential economic dislocation. Use of oil from the SPR has helped to minimize the economic effect of those events."
CRS Report for Congress, R45577
Congressional Research Service: https://crsreports.congress.gov/