| 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 & J Oil Company | Kermit, TX 79745 | Oil & Gas Operator | Oct 2025 |
| 4 | D & T Swabbing & Well Serv Inc | Hennessey, OK 73742-0124 | Oil & Gas Operator | Jun 2025 |
| 5 | D C Energy, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2020 |
| 6 | Dakota Oil Company | Hebbronville, TX 78361 | Oil & Gas Operator | Oct 2025 |
| 7 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 8 | Damson Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Mar 2005 |
| 9 | Daube Company The | Ardmore, OK 73401 | Oil & Gas Operator | Jul 2025 |
| 10 | Davis & Davis | | Oil & Gas Operator | Dec 2021 |
| 11 | Davis Operating Company | Elysian Field, TX 75642 | Oil & Gas Operator | Oct 2025 |
| 12 | Dawson Resources Inc | Franktown, CO 80116 | Oil & Gas Operator | Mar 2015 |
| 13 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 14 | Deaton, Gary L. Corporation | Oklahoma City, OK 73105 | Oil & Gas Operator | Mar 2015 |
| 15 | Delong Ralph J | Sapulpa, OK 74066 | Oil & Gas Operator | Nov 2005 |
| 16 | Deminex U.S. Oil Company | | Oil & Gas Operator | Jan 1998 |
| 17 | Denveramerican Petro LLC | | Oil & Gas Operator | May 2006 |
| 18 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 19 | Devon Energy Operating Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2013 |
| 20 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 21 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 22 | Devon Resources Corporation | Jenks, OK 74037-3525 | Oil & Gas Operator | May 2025 |
| 23 | Diamond A Inc. | Tulsa, OK 74137 | Oil & Gas Operator | Jun 2001 |
| 24 | Diamond B Company Inc | Tulsa, OK 74170 | Oil & Gas Operator | Dec 2010 |
| 25 | Diamond Energy Operating Company | Tulsa, OK 74137 | Oil & Gas Operator | Mar 2005 |
| 26 | Diamond Production Company LLC | Irving, TX 75016-7853 | Oil & Gas Operator | Jun 2025 |
| 27 | Dinsmore C E | Enid, OK 73702 | Oil & Gas Operator | May 2009 |
| 28 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Oct 2025 |
| 29 | Dixie Petroleum Inc | Cashion, OK 73016 | Oil & Gas Operator | May 2001 |
| 30 | DKT Energy LLC | Edmond, OK 73083-6844 | Oil & Gas Operator | Sep 2014 |
| 31 | DLB Energy Corporation | Oklahoma City, OK 73118-1401 | Oil & Gas Operator | Dec 2014 |
| 32 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Oct 2025 |
| 33 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Aug 2025 |
| 34 | Doco Development Corporation | Norman, OK 73072 | Oil & Gas Operator | Jun 2025 |
| 35 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 36 | Dominion Ok TX E & P Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2018 |
| 37 | Donaldson Richard E | Bartlesville, OK 74005-0032 | Oil & Gas Operator | Nov 2005 |
| 38 | Dorchester Resources LP | Oklahoma City, OK 73154-8879 | Oil & Gas Operator | Aug 2021 |
| 39 | Double H Petroleum Corporation | Tulsa, OK 74136-5414 | Oil & Gas Operator | May 2006 |
| 40 | Draco Production Company | Tulsa, OK 74133 | Oil & Gas Operator | Jul 2012 |
| 41 | Duncan Oil Properties, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 42 | Dyco Petroleum Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |