L. SUPPLEMENTARY FINANCIAL INFORMATION ON OIL AND NATURAL GAS EXPLORATION, DEVELOPMENT (Details - Future cash flows) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Extractive Industries [Abstract]
Future oil and gas cash inflows	$ 8,292	$ 10,653
Future oil & gas operating expenses	(1,478)	(3,425)
Future development costs	(1,400)	(1,480)
Future tax expense	(590)	(724)
Future net cash flows	4,824	5,024
10% discount to reflect timing of cash flows	(1,853)	(2,303)
Standardized measure of future cash flows	$ 2,971	$ 2,721