43 U.S.C. § 1865

The Secretary of the Interior shall conduct a continuing investigation to determine an estimate of the total discovered crude oil and natural gas reserves by fields (including proved and indicated reserves) and undiscovered crude oil and natural gas resources (including hypothetical and speculative resources) of the Outer Continental Shelf. The Secretary of the Interior shall provide a biennial report to Congress on June 30 of every odd numbered year on the results of such investigation.