| 1 | Gaither Petroleum Corporation | Katy, TX 77493 | Oil & Gas Operator | Dec 2025 |
| 2 | Gary-Williams Production Company | Denver, CO 80202 | Oil & Gas Operator | May 2000 |
| 3 | General American Oil Co Of TX | | Oil & Gas Operator | Jun 1983 |
| 4 | Geodyne Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2015 |
| 5 | Germany Operating Company | Houston, TX 77090 | Oil & Gas Operator | Sep 2011 |
| 6 | Getty Oil Company | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |
| 7 | Goldking Onshore Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2016 |
| 8 | Goldking Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 9 | Goodrich Oil Company | Shreveport, LA 71101 | Oil & Gas Operator | Nov 2001 |
| 10 | Goodrich Petroleum Company | Houston, TX 77002 | Oil & Gas Operator | Feb 2022 |
| 11 | Graham Exploration, LTD. | | Oil & Gas Operator | Oct 1993 |
| 12 | Great Southern - Joe Scates | | Oil Operator | Dec 1979 |
| 13 | Great Southern Oil &Gas Co Inc | | Oil & Gas Operator | Dec 2004 |
| 14 | Great Southern-Caddo-Lyons | | Oil & Gas Operator | Sep 1982 |
| 15 | Greystone Operating, Inc. | | Oil & Gas Operator | Nov 2009 |
| 16 | Grigsby Petroleum Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2025 |
| 17 | Gulf Oil Corp. | Denver, CO 80201-0599 | Oil & Gas Operator | Dec 2014 |
| 18 | Gulf South Pipeline Company, LP | Houston, TX 77001 | Oil & Gas Operator | Dec 2020 |