They actually performed better than expected. Strategic petroleum reserves proved to be surprisingly effective in helping markets adjust to the disruption.
However, inventories were only part of the story. China, Japan and South Korea also reduced their oil purchases instead of trying to maintain previous import levels. For example, when China's imports declined, it eased pressure on global oil prices. Japan and South Korea followed a similar approach. Even the United States, despite being a net oil exporter, reduced its imports during the crisis.
In other words, strategic reserves gave these countries the flexibility to lower imports without disrupting domestic supply, helping stabilize the global oil market during a period of significant uncertainty.
Consumption did decline somewhat, but nowhere near as much as crude oil imports. Countries were able to maintain most of their domestic consumption while reducing imports, which helped ease upward pressure on global oil prices.
That brings us back to the role of strategic petroleum reserves. If a country has built up substantial inventories before a crisis, it can draw on those reserves when supplies are disrupted. Instead of buying the same volume of oil from the market, it can temporarily rely on its stockpiles.
Of course, that strategy assumes the crisis will eventually be resolved because inventories are not unlimited. But having significant reserves gives governments valuable time to adjust while waiting for normal supplies to resume.