| 1 | O H Berry | Midland, TX 79702 | Oil & Gas Operator | Feb 2003 |
| 2 | O'Neil Properties LTD | Midland, TX 79702 | Oil & Gas Operator | Jun 2015 |
| 3 | O. H. B. Inc. | San Angelo, TX 76902 | Oil & Gas Operator | Sep 2019 |
| 4 | Occidental Permian LTD. | Houston, TX 77046 | Oil & Gas Operator | Dec 2025 |
| 5 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 6 | Ogs Operating Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Sep 2008 |
| 7 | Ogx Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 8 | Oil & Gas Operations | Midland, TX 79706 | Oil & Gas Operator | Dec 2025 |
| 9 | Ok Operating Co | Midland, TX 79702 | Oil & Gas Operator | Aug 1999 |
| 10 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2025 |
| 11 | Okie Operating Company, LTD. | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2025 |
| 12 | Oleum Energy LLC | Georgetown, TX 78628 | Oil & Gas Operator | Sep 2025 |
| 13 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | Dec 2025 |
| 14 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 15 | Oneenergy Partners Operating, LLC | Houston, TX 77019 | Oil & Gas Operator | Nov 2018 |
| 16 | Onshore Royalties LLC | Houston, TX 77269 | Oil & Gas Operator | Sep 2025 |
| 17 | Opal Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | Dec 2025 |
| 18 | Orbit Enterprises, Inc. | Lovington, NM 88260 | Oil & Gas Operator | Mar 2015 |
| 19 | Orbit Petroleum, Inc. | Irving, TX 75038 | Oil & Gas Operator | Sep 2010 |
| 20 | Orbrie Luman | Odessa, TX 79761 | Oil & Gas Operator | Jul 2025 |
| 21 | Orion Oil & Gas Prop | Roswell, NM 88202 | Oil & Gas Operator | Apr 1998 |
| 22 | Orla Petco Inc & Hopi Drilling Co | Midland, TX 79702 | Oil Operator | Sep 2004 |
| 23 | Orla Petco, Inc. | Midland, TX 79708 | Oil & Gas Operator | Dec 2025 |
| 24 | Orville S Slaughter Jr | Denver, CO 80205 | Oil & Gas Operator | Aug 2000 |
| 25 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 26 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 27 | Oso Perdido Services LLC | Flatonia, TX 78941 | Oil Operator | Sep 2025 |
| 28 | Ostrich Oil & Gas, LLC | Midland, TX 79701 | Oil & Gas Operator | Dec 2025 |
| 29 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2025 |
| 30 | Owens Pet Inc | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 31 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Dec 2025 |
| 32 | Oxy USA WTP Limited Partnership | Houston, TX 772104294 | Oil & Gas Operator | Sep 2025 |
| 33 | Ozark Exploration, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Dec 2025 |