| 1 | Halcon Resources Operating, Inc. | Tulsa, OK 74135 | Oil & Gas Operator | Dec 2013 |
| 2 | Helis Oil & Gas Company, L.L.C. | New Orleans, LA 70130 | Oil & Gas Operator | Oct 2023 |
| 3 | Hicks Production Co. | | Oil & Gas Operator | Apr 1991 |
| 4 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Nov 2024 |
| 5 | Hilliard Oil & Gas Inc | New Orleans, LA 70112 | Oil & Gas Operator | May 2001 |
| 6 | Houma Operating Company, Inc. | | Oil & Gas Operator | Jun 1998 |
| 7 | Houston Energy Operating, L.P. | Houston, TX 77002 | Oil & Gas Operator | Jul 2020 |
| 8 | Hubco Exploration Inc. | Houston, TX 77073 | Oil & Gas Operator | Sep 2002 |
| 9 | Hughes Denny Offshore Expl Inc | | Oil & Gas Operator | Nov 1988 |
| 10 | Hughes Eastern Petroleum, Inc. | | Oil & Gas Operator | Apr 1993 |
| 11 | Hughes-Denny Petroleum Co.,Inc | | Oil & Gas Operator | Dec 1987 |
| 12 | Hughes-Nicklaus Oil Co., LTD. | | Oil & Gas Operator | Feb 1986 |
| 13 | Hunt Industries, LTD. | Dallas, TX 75201 | Oil & Gas Operator | Nov 2000 |