L. SUPPLEMENTARY FINANCIAL INFORMATION ON OIL AND NATURAL GAS EXPLORATION, DEVELOPMENT (Details - Future cash flows) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Extractive Industries [Abstract]
Future oil and gas cash inflows	$ 10,653	$ 19,368
Future oil & gas operating expenses	(3,425)	(4,605)
Future development costs	(1,480)	(2,982)
Future tax expense	(724)	(1,308)
Future net cash flows	5,024	10,473
10% discount to reflect timing of cash flows	(2,303)	(4,150)
Standardized measure of future cash flows	$ 2,721	$ 6,323