| 1 | Samson Contour Energy E&P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2017 |
| 2 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2024 |
| 3 | Saxon Oil & Gas Expl., Inc. | | Gas Operator | Nov 1989 |
| 4 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 5 | Seagull Mid-South Inc | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 6 | Segars Operating | | Gas Operator | Apr 2014 |
| 7 | Shiloh Creek Resources, Inc. | | Gas Operator | Jun 2024 |
| 8 | Shuler Drilling Co., Inc. | El Dorado, AR 71730 | Oil & Gas Operator | Jul 2024 |
| 9 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Sep 2024 |
| 10 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 11 | Southern Natural Gas Co | Houston, TX 77001 | Oil & Gas Operator | Dec 2011 |
| 12 | Spillers Petroleum, Inc. | | Gas Operator | Mar 2010 |
| 13 | Spirit Petroleum Company | | Oil & Gas Operator | Apr 1999 |
| 14 | Strahan Oil & Gas Co., Inc. | | Gas Operator | Oct 1983 |
| 15 | Strataform, Inc. | | Gas Operator | Jun 2002 |
| 16 | Stroud Petroleum, Inc. | Shreveport, LA 71162 | Oil & Gas Operator | Nov 2024 |
| 17 | Summit Energy, Inc. | Littleton, CO 80127 | Oil & Gas Operator | Aug 2013 |
| 18 | Summit Overseas Expl., Inc. | Denver, CO 80226 | Oil & Gas Operator | Apr 2007 |
| 19 | Sun Exploration-Production Co. | | Oil & Gas Operator | Jan 1990 |
| 20 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |