Segment information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Revenue:
Oil and gas revenue	$ 3,591	$ 5,398
Other revenue	296	321
Total revenue	3,887	5,719
Less:
Depletion and amortization	1,589	3,002
Lease operating expense	303	352
Transportation and processing expense	151	222
Insurance expense	65	90
Workover expense	1	43
Management fees to affiliate	508	515
Other segment items	132	149
Net income	$ 1,138	$ 1,346