| 1 | D & B Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2003 |
| 2 | D & V Oil Co., LP | San Angelo, TX 76909 | Oil & Gas Operator | Jan 2019 |
| 3 | D And B Oil | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 4 | D G D Oil Co. | Imperial, TX 79743 | Oil & Gas Operator | Oct 2025 |
| 5 | Dakota Resources, Inc | Midland, TX 79707 | Oil & Gas Operator | Jun 2025 |
| 6 | Dakota Resources, Inc. (I) | Midland, TX 79707 | Oil & Gas Operator | Oct 2025 |
| 7 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 8 | Dallas Operating Corp. | Dallas, TX 75205 | Oil & Gas Operator | Nov 2006 |
| 9 | Dally'S Oil Co. LLC | Monahans, TX 79756 | Oil Operator | Oct 2025 |
| 10 | Darkens Oil & Gas Inc. | MC Camey, TX 79752 | Oil & Gas Operator | Oct 2025 |
| 11 | Dawson Operating Company | Midland, TX 79702 | Oil & Gas Operator | Dec 1994 |
| 12 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 13 | Dean Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | Nov 2019 |
| 14 | Deg Energy, Inc. | Magnolia, TX 77354 | Oil & Gas Operator | Feb 2007 |
| 15 | Delek Energy Systems Us Inc | Denver, CO 80202 | Oil & Gas Operator | Oct 2011 |
| 16 | Delhi Gas Pipeline Corporation | Palestine, TX 75802 | Oil & Gas Operator | Feb 1998 |
| 17 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 18 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 19 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 20 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 21 | Diamond G Production | FT Stockton, TX 79735 | Oil & Gas Operator | Oct 2025 |
| 22 | Diamond M Oil Co., Inc. | Monahans, TX 79756 | Oil & Gas Operator | Oct 2025 |
| 23 | Diamondback E&P LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 24 | Dinero Operating Co | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 25 | Discovery Operating Inc | Midland, TX 79705 | Oil & Gas Operator | Oct 2025 |
| 26 | Dittman, D. W. | Big Lake, TX 76932 | Oil & Gas Operator | Mar 2007 |
| 27 | Dixon, N. D. | Midland, TX 79702 | Oil & Gas Operator | Feb 2003 |
| 28 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Oct 2025 |
| 29 | Dolch Production, Inc. | San Antonio, TX 78248 | Oil & Gas Operator | Jul 1996 |
| 30 | Dominion Natural Resources LLC | Dallas, TX 75367 | Oil & Gas Operator | Oct 2025 |
| 31 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 32 | Double Barrel Oil LLC | Brenham, TX 77834 | Oil & Gas Operator | Oct 2025 |
| 33 | Double Eagle Petroleum Corp | Evansville, IN 47725 | Oil & Gas Operator | Oct 2025 |
| 34 | Draco Energy, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 35 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 36 | Drillmar Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | Nov 2014 |
| 37 | DSR Oil & Gas, Inc. | Monahans, TX 79756 | Oil & Gas Operator | Oct 2025 |
| 38 | Dudley Oil Co. | Crane, TX 79731 | Oil & Gas Operator | Jan 2006 |
| 39 | Dugan Production Corp | Farmington, NM 87499 | Oil & Gas Operator | Jul 2025 |
| 40 | Dundee Oil & Supply Inc | Tulsa, OK 74101 | Oil & Gas Operator | Apr 2001 |
| 41 | Dundee Petroleum, Inc. | Buffalo Gap, TX 79508 | Oil & Gas Operator | Aug 2003 |
| 42 | Dune Oil And Gas, Inc. | Odessa, TX 79768 | Oil & Gas Operator | Aug 2006 |
| 43 | Durango Resources Corp. | Houston, TX 77043 | Oil & Gas Operator | Oct 2025 |
| 44 | Dyad Petroleum Company | Midland, TX 79710 | Oil & Gas Operator | Sep 2021 |