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Note 10 - Supplemental Financial Data - Oil and Gas Producing Activities (Unaudited): Schedule of Proved Developed and Undeveloped Oil and Gas Reserve Quantities (Details)
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2019
Details      
Net Proved Developed And Undeveloped Reserves 1,000 1,100 2,400
Proved Developed And Undeveloped Reserves, Revisions of previous estimates 700 (700)  
Proved Developed And Undeveloped Reserve, Production (800) (600)