| 1 | H & B Well Service, Inc. | | Oil & Gas Operator | Aug 1993 |
| 2 | H. B. McCullough | | Oil Operator | Oct 2004 |
| 3 | H. E. Sutton | | Oil & Gas Operator | Jan 1990 |
| 4 | H. J. Bonner | | Oil & Gas Operator | Aug 1991 |
| 5 | H.E. Sutton, Et Al | | Oil & Gas Operator | Jan 1990 |
| 6 | Hall Engineering, Inc. | | Oil & Gas Operator | Jan 2007 |
| 7 | Hallmark Oil And Gas Co., Inc. | | Oil & Gas Operator | Dec 2024 |
| 8 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 9 | Hardey Co., The | Shreveport, LA 71107 | Oil & Gas Operator | Oct 2025 |
| 10 | Harleton Oil & Gas Inc. | Tyler, TX 75710 | Oil & Gas Operator | Oct 2025 |
| 11 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 12 | Heritage Energy Company | | Oil & Gas Operator | Jun 2001 |
| 13 | Herlin Et Al | | Oil & Gas Operator | Mar 1985 |
| 14 | High-Hope Oil And Gas, Inc | | Oil & Gas Operator | Mar 2017 |
| 15 | Highlands Operating Co., Inc. | | Oil & Gas Operator | May 1990 |
| 16 | Hilburn Ind., Inc. | | Oil Operator | Jan 1978 |
| 17 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Oct 2025 |
| 18 | Hilliard Petroleum Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Sep 2009 |
| 19 | HS Resources, Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2005 |
| 20 | Hughes, Wise & Assoc., Inc | | Oil Operator | Jul 1987 |
| 21 | Hunt Petroleum Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 22 | Hurley Oil And Gas Company | | Oil & Gas Operator | Jan 1997 |
| 23 | Hurley Petroleum Corporation | Baton Rouge, LA 70821 | Oil & Gas Operator | Feb 2000 |