| 1 | Gas & Oil Management Inc | Englewood, CO 80112 | Oil & Gas Operator | Dec 1974 |
| 2 | Gas Producing Enterprises | Houston, TX 77046 | Oil & Gas Operator | Dec 1983 |
| 3 | Gasco Production Company | Denver, CO 80237 | Oil & Gas Operator | Dec 2015 |
| 4 | Gavilan Petroleum Inc | Park City, UT 84060 | Oil & Gas Operator | Dec 2006 |
| 5 | General Minerals Corp | Oklahoma City, OK 73105 | Oil & Gas Operator | Dec 2015 |
| 6 | General Petroleum Corp | Sand Springs, OK 74063-6646 | Oil & Gas Operator | Jul 2015 |
| 7 | Genesis St Operating LLC | Kansas City, MO 64108 | Oil & Gas Operator | Dec 2025 |
| 8 | Geophysical Survey Company | Grand Junction, CO 81503-1296 | Oil & Gas Operator | Jan 1996 |
| 9 | Getty Oil Company | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |
| 10 | Giant Explor & Prod Co | Farmington, NM 87499 | Oil & Gas Operator | Aug 1996 |
| 11 | Gilmore Oil And Gas Co | Austin, TX 78768-4729 | Oil & Gas Operator | Jan 1997 |
| 12 | Global Natural Res Corp | Houston, TX 77210 | Oil & Gas Operator | Dec 1994 |
| 13 | Gordon Creek, LLC | Calgary, AB T2P 3P8 | Gas Operator | Oct 2019 |
| 14 | Grace Petroleum Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Oct 1997 |
| 15 | Graham Energy LTD | Houston, TX 77024 | Oil & Gas Operator | Mar 1994 |
| 16 | Graham Resources Inc | Denver, CO 80202 | Oil & Gas Operator | Apr 1988 |
| 17 | Graham Royalty LTD | Covington, LA 70434 | Oil & Gas Operator | Jul 2007 |
| 18 | Grand Resources | Salt Lake City, UT 84115 | Oil & Gas Operator | Apr 1992 |
| 19 | Great Northern Gas Company | Denver, CO 80293-0602 | Oil & Gas Operator | Jun 2016 |
| 20 | Great Western Drilling Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2025 |
| 21 | Greenwood Holding Inc | Englewood, CO 80110 | Oil & Gas Operator | Jun 1993 |
| 22 | Greylock Production LLC | Charleston, WV 25311-1264 | Oil & Gas Operator | Sep 2025 |
| 23 | Grynberg, Jack J. | Denver, CO 80237 | Oil & Gas Operator | Jun 2021 |
| 24 | Guffey & Galey | | Oil & Gas Operator | Aug 1981 |
| 25 | Gulf Energy Corporation | Denver, CO 80237 | Oil & Gas Operator | Jun 1987 |
| 26 | Gulf Oil Corp. | Denver, CO 80201-0599 | Oil & Gas Operator | Dec 2014 |
| 27 | Gulf Production Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Apr 2015 |
| 28 | GW Petroleum Inc | Houston, TX 77002 | Oil & Gas Operator | Apr 1993 |