| 1 | D & B Operating LLC | Ringwood, OK 73768 | Oil Operator | Jan 2023 |
| 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 & J Oil Company Of Okla Inc | Enid, OK 73706-0129 | Oil & Gas Operator | May 1999 |
| 5 | D & T Swabbing & Well Serv Inc | Hennessey, OK 73742-0124 | Oil & Gas Operator | Jun 2025 |
| 6 | D C Energy, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2020 |
| 7 | Dalcor Energy LLC | Duncan, OK 73534 | Oil & Gas Operator | Jun 2025 |
| 8 | Damson Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Mar 2005 |
| 9 | Dance Oil Company | Denver, CO 80202 | Oil & Gas Operator | May 1993 |
| 10 | Darrah Oil Company LLC | Wichita, KS 67201 | Oil & Gas Operator | Oct 2025 |
| 11 | Dash Operating LLC | Oklahoma City, OK 73118-5031 | Oil & Gas Operator | Jun 2025 |
| 12 | David E Morgan Inc | Danville, CA 94506-2035 | Oil & Gas Operator | Jul 2025 |
| 13 | Dawson Resources Inc | Franktown, CO 80116 | Oil & Gas Operator | Mar 2015 |
| 14 | Dawson-Markwell Exploration Co. | Oklahoma City, OK 73101 | Oil & Gas Operator | Jun 2025 |
| 15 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 16 | Deaton, Gary L. Corporation | Oklahoma City, OK 73105 | Oil & Gas Operator | Mar 2015 |
| 17 | Delta D Operations | Wilson, OK 73463 | Oil & Gas Operator | Jul 2014 |
| 18 | Deminex U.S. Oil Company | | Oil & Gas Operator | Jan 1998 |
| 19 | Dette Oil Corporation | Oklahoma City, OK 73162-6249 | Oil & Gas Operator | Oct 2015 |
| 20 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 21 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 22 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 23 | Dinsmore C E | Enid, OK 73702 | Oil & Gas Operator | May 2009 |
| 24 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Oct 2025 |
| 25 | Dixie Petroleum Inc | Cashion, OK 73016 | Oil & Gas Operator | May 2001 |
| 26 | DLB Energy Corporation | Oklahoma City, OK 73118-1401 | Oil & Gas Operator | Dec 2014 |
| 27 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Oct 2025 |
| 28 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Aug 2025 |
| 29 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 30 | Dominion Ok TX E & P Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2018 |
| 31 | Dorchester Resources LP | Oklahoma City, OK 73154-8879 | Oil & Gas Operator | Aug 2021 |
| 32 | Dorey Oil Corporation | Healdton, OK 73438-0856 | Oil Operator | Apr 2014 |
| 33 | Douglass Dietz & Daley Inc | Oklahoma City, OK 73154-0125 | Oil & Gas Operator | Aug 2023 |
| 34 | Draco Production Company | Tulsa, OK 74133 | Oil & Gas Operator | Jul 2012 |
| 35 | Drake Exploration Inc | Tulsa, OK 74105-4250 | Oil & Gas Operator | Jul 2025 |
| 36 | Driver Energy Of Texas | Dallas, TX 75379-5951 | Oil & Gas Operator | Apr 2011 |
| 37 | Duncan Jr J Walter | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2016 |
| 38 | Duncan Oil Properties, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 39 | Dyco Petroleum Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |