| 1 | Amerada Hess Corporation | Houston, TX 77252 | Oil & Gas Operator | Aug 2013 |
| 2 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 3 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Jul 2025 |
| 4 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 5 | Atinum Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Jan 2014 |
| 6 | BNP Petroleum Corporation | Corpus Chrsti, TX 78478 | Oil & Gas Operator | Oct 2025 |
| 7 | Chaparral Energy, L.L.C. | Oklahoma City, OK 73142 | Oil & Gas Operator | Oct 2025 |
| 8 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 9 | Corenergy Operating Group, LLC | Houston, TX 77074 | Oil & Gas Operator | Oct 2025 |
| 10 | Davis Gulf Coast, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2025 |
| 11 | Davis Petroleum Corp. | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 12 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 13 | El Paso Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 14 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 15 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 16 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 17 | Fieldwood Energy LLC | Houston, TX 77042 | Oil & Gas Operator | Dec 2024 |
| 18 | Hall-Houston Oil Company | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 19 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 20 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 21 | Llog Expl. Co. | Metairie, LA 70005 | Oil & Gas Operator | Jan 2003 |
| 22 | Llog Exploration Offshore, Inc. | Covington, LA 70433 | Oil & Gas Operator | Aug 2004 |
| 23 | Llog Exploration Texas, L.P. | Covington, LA 70433 | Oil & Gas Operator | Oct 2025 |
| 24 | Llog Production Company | Metairie, LA 70005 | Oil & Gas Operator | Apr 1995 |
| 25 | Locin Oil Corporation | Katy, TX 77494 | Oil & Gas Operator | Oct 2025 |
| 26 | Lone Pine Production Assoc.,Inc. | Houston, TX 77056 | Oil & Gas Operator | Apr 1993 |
| 27 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 28 | Magellan E&P Holdings, Inc. | Houston, TX 77056 | Oil & Gas Operator | Jun 2021 |
| 29 | Mariner Energy, Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 30 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 31 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 32 | Modena Operating LLC | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 33 | National Energy Group, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 34 | Opmi Operating Company | Houston, TX 77057 | Oil & Gas Operator | Jun 2008 |
| 35 | Osprey Petroleum Company, Inc. | Manvel, TX 77578 | Oil & Gas Operator | May 2020 |
| 36 | Petrotex Engineering Company | Cypress, TX 77429 | Oil & Gas Operator | Oct 2025 |
| 37 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 38 | Probe Offshore, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2009 |
| 39 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 40 | Sabco Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2011 |
| 41 | Sabco Operating Company, LLC | Houston, TX 77056 | Oil & Gas Operator | Jun 2018 |
| 42 | Samedan Oil Corp. -Offshore Div. | Houston, TX 77067 | Oil & Gas Operator | Dec 2002 |
| 43 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 44 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 45 | Sterling Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2015 |
| 46 | Tana Oil And Gas Corporation | Irving, TX 75062 | Oil & Gas Operator | Mar 2000 |
| 47 | TR Offshore, LLC | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Oct 2025 |
| 48 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 49 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 50 | White Marlin Operating Company, LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |