| 1 | D & B Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2003 |
| 2 | D & D Pipe & Equipment Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Mar 2005 |
| 3 | D & G Oil & Gas Company Inc | Enid, OK 73702-2027 | Oil & Gas Operator | Nov 2021 |
| 4 | D & J Oil Company | Kermit, TX 79745 | Oil & Gas Operator | Jun 2025 |
| 5 | D & J Oil Company Of Okla Inc | Enid, OK 73706-0129 | Oil & Gas Operator | May 1999 |
| 6 | D C Energy, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2020 |
| 7 | Dab And Associates Inc | Crescent, OK 73028-0580 | Oil & Gas Operator | Nov 2014 |
| 8 | Dar-Lon Operating Company | Lamont, OK 74643 | Oil & Gas Operator | Oct 2000 |
| 9 | Darling Dan Oil | | Oil & Gas Operator | Sep 2018 |
| 10 | Darling Oil Corporation | Lamont, OK 74643 | Oil & Gas Operator | Feb 2025 |
| 11 | Darrah Oil Company LLC | Wichita, KS 67201 | Oil & Gas Operator | Jun 2025 |
| 12 | Dart Oil Properties | Enid, OK 73703 | Oil & Gas Operator | Oct 1992 |
| 13 | Davco Productions Inc | Springer, OK 73458-8191 | Oil & Gas Operator | Jun 2021 |
| 14 | David E Morgan Inc | Danville, CA 94506-2035 | Oil & Gas Operator | Feb 2025 |
| 15 | Davis Operating Company | Elysian Field, TX 75642 | Oil & Gas Operator | Jun 2025 |
| 16 | Davis, William H. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2014 |
| 17 | Davon Drilling Company | Oklahoma City, OK 73113-0665 | Oil & Gas Operator | Mar 2015 |
| 18 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Feb 2025 |
| 19 | Deck Oil Company | Tulsa, OK 74101 | Oil & Gas Operator | Jun 2020 |
| 20 | Deka Exploration Inc | Oklahoma City, OK 73113-0057 | Oil & Gas Operator | Nov 2019 |
| 21 | Dem Operations Inc | Lamont, OK 74643-5010 | Oil & Gas Operator | Mar 2025 |
| 22 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 23 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 24 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 25 | Dinsmore C E | Enid, OK 73702 | Oil & Gas Operator | May 2009 |
| 26 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Jun 2025 |
| 27 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Jun 2025 |
| 28 | Dolphin Energy LLC | Lake Worth, FL 33467 | Oil & Gas Operator | Feb 2025 |
| 29 | Dominion Ok TX E & P Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2018 |
| 30 | Douglass Dietz & Daley Inc | Oklahoma City, OK 73154-0125 | Oil & Gas Operator | Aug 2023 |
| 31 | Draco Production Company | Tulsa, OK 74133 | Oil & Gas Operator | Jul 2012 |
| 32 | Drake Exploration Inc | Tulsa, OK 74105-4250 | Oil & Gas Operator | Mar 2025 |
| 33 | Duncan Oil Properties, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2025 |
| 34 | Dune Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Jan 1993 |
| 35 | Dyco Petroleum Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |