I didn't know that either.
Excerpt from link below:
DOE intends to draw down and sell 10.1 million barrels of crude oil from the SPR. This notice of sale is to fulfill the requirements of Section 403(a)(4) of the Bipartisan Budget Act of 2015 (5 million barrels) and the Consolidated Appropriations Act of 2018 (5.1 million barrels), which combined require a mandatory sale of 10.1 million barrels during FY 2021. The proceeds of the sale will be deposited in the U.S. Treasury by the end of the Fiscal Year.
https://www.energy.gov/articles/doe-announces-notice-sale-crude-oil-strategic-petroleum-reserve-1