| 1 | D & B Operating LLC | Ringwood, OK 73768 | Oil Operator | Jan 2023 |
| 2 | D & J Oil Company | Kermit, TX 79745 | Oil & Gas Operator | Oct 2025 |
| 3 | D & J Oil Company Of Okla Inc | Enid, OK 73706-0129 | Oil & Gas Operator | May 1999 |
| 4 | D C Energy, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2020 |
| 5 | Dalcor Energy LLC | Duncan, OK 73534 | Oil & Gas Operator | Jun 2025 |
| 6 | Damson Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Mar 2005 |
| 7 | Darrah Oil Company LLC | Wichita, KS 67201 | Oil & Gas Operator | Oct 2025 |
| 8 | Davon Drilling Company | Oklahoma City, OK 73113-0665 | Oil & Gas Operator | Mar 2015 |
| 9 | Dawson Resources Inc | Franktown, CO 80116 | Oil & Gas Operator | Mar 2015 |
| 10 | Dawson, Levi S | | Oil & Gas Operator | Mar 2015 |
| 11 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 12 | Dehart Company (The) | Ardmore, OK 73402 | Oil & Gas Operator | Jul 2025 |
| 13 | Delta D Operations | Wilson, OK 73463 | Oil & Gas Operator | Jul 2014 |
| 14 | Deminex U.S. Oil Company | | Oil & Gas Operator | Jan 1998 |
| 15 | Dennett'S Inc | Enid, OK 73701-1851 | Oil & Gas Operator | Apr 2014 |
| 16 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 17 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 18 | Diamond A Inc. | Tulsa, OK 74137 | Oil & Gas Operator | Jun 2001 |
| 19 | Diamond Energy Operating Company | Tulsa, OK 74137 | Oil & Gas Operator | Mar 2005 |
| 20 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Oct 2025 |
| 21 | DLB Energy Corporation | Oklahoma City, OK 73118-1401 | Oil & Gas Operator | Dec 2014 |
| 22 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Oct 2025 |
| 23 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Aug 2025 |
| 24 | Dolphin Energy LLC | Lake Worth, FL 33467 | Oil & Gas Operator | Jun 2025 |
| 25 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 26 | Dominion Ok TX E & P Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2018 |
| 27 | Dorado E & P Partners LLC | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2025 |
| 28 | Dorchester Resources LP | Oklahoma City, OK 73154-8879 | Oil & Gas Operator | Aug 2021 |
| 29 | DRG Energy Inc | Norman, OK 73026-3171 | Oil & Gas Operator | Jun 2025 |