| 1 | D C Energy, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2020 |
| 2 | Dabb Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Aug 2020 |
| 3 | Daco, Inc. | Spearman, TX 79081 | Oil & Gas Operator | Mar 2025 |
| 4 | Dalf Energy LLC | Pampa, TX 79066 | Oil & Gas Operator | Mar 2025 |
| 5 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 6 | Daniels Energy | Pampa, TX 79066 | Oil & Gas Operator | Mar 2025 |
| 7 | Daniels, J.C. Energy | Pampa, TX 79066 | Oil & Gas Operator | Apr 2001 |
| 8 | Davenport, Vernon | Shamrock, TX 79079 | Oil & Gas Operator | Mar 2008 |
| 9 | Davenport, Vernon Prod. Co. | Dumas, TX 79029 | Oil & Gas Operator | Jan 2002 |
| 10 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Nov 2024 |
| 11 | DDC Track, LLC | Bushland, TX 79012 | Oil Operator | Mar 2025 |
| 12 | Dee'S Oil | Wellington, TX 79095 | Oil & Gas Operator | Mar 2008 |
| 13 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Mar 2025 |
| 14 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 15 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2025 |
| 16 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 17 | Diamond S Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Mar 2025 |
| 18 | Diamondback E&P LLC | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 19 | Discovery Operating Inc | Midland, TX 79705 | Oil & Gas Operator | Mar 2025 |
| 20 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Mar 2025 |
| 21 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 22 | Donalu Oil | Pampa, TX 79066 | Oil & Gas Operator | Mar 2025 |
| 23 | Douglas, Norvel Trust | H SPG NTL PK, AR 71909 | Oil & Gas Operator | Aug 2013 |
| 24 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 25 | Dunne Equities Operating Inc | Houston, TX 77057 | Oil & Gas Operator | Aug 2022 |
| 26 | Dunne Equities, Inc. | Wichita, KS 67226 | Oil & Gas Operator | Apr 2014 |