UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 REPORT ON FORM 10-K (Mark one) Commission File No. 1-15555 TENGASCO, INC. (name of registrant as specified in its charter) Delaware 87-0267438 (state or other jurisdiction of Incorporation or organization) 8000 E. Maplewood Ave., Suite 130, Greenwood Village, CO 80111 (Address of Principal Executive Offices) (Zip Code) (I.R.S. Employer Identification No.) Registrant's telephone number, including area code: (720) 420-4460. Securities reg ...