| 2001 | Hardco, Inc. | Cleveland, OH 44115 | Oil & Gas Operator | Dec 1992 |
| 2002 | Hardey Co., The | Shreveport, LA 71107 | Oil & Gas Operator | Apr 2025 |
| 2003 | Hardey Production Company | | Oil Operator | Dec 1998 |
| 2004 | Hardy Oil & Gas USA Inc. | Houston, TX 77079 | Oil & Gas Operator | Jun 1996 |
| 2005 | Hargraves Daughters | | Oil Operator | Mar 1992 |
| 2006 | Hargraves Production, LLC | | Oil Operator | Jan 2025 |
| 2007 | Harleton Oil & Gas Inc. | Tyler, TX 75710 | Oil & Gas Operator | Apr 2025 |
| 2008 | Harold H. Hollenshead | | Oil & Gas Operator | May 2002 |
| 2009 | Harrison & Lee | | Oil Operator | Sep 1996 |
| 2010 | Harry L. Neeb | | Oil Operator | May 1985 |
| 2011 | Hart & McFarland | Vivian, LA 71082 | Oil & Gas Operator | Apr 2025 |
| 2012 | Hartco Oil Co. | | Oil Operator | Jan 2025 |
| 2013 | Harter Oil Company | | Oil & Gas Operator | Apr 2011 |
| 2014 | Harvard Investments, Inc. | | Oil & Gas Operator | Oct 2002 |
| 2015 | Harvest Oil & Gas, LLC | | Oil & Gas Operator | Feb 2012 |
| 2016 | Harvest Petroleum Inc. | Frisco, TX 75033 | Oil & Gas Operator | Apr 2025 |
| 2017 | Harvey Broyles | | Oil & Gas Operator | May 2012 |
| 2018 | Harvey Broyles & Munoco Co. | | Oil & Gas Operator | Jan 2002 |
| 2019 | Harvey Broyles, Et Al | | Gas Operator | Nov 1985 |
| 2020 | Hassie Hunt Expl. Company | Dallas, TX 75201 | Oil & Gas Operator | Aug 2008 |
| 2021 | Haw Corporation | | Oil Operator | Dec 1979 |
| 2022 | Hawk Oil Co. | Luling, TX 78648 | Oil & Gas Operator | Aug 2003 |
| 2023 | Hawkeye Drilling Co. | Waskom, TX 75692 | Oil & Gas Operator | Feb 2023 |
| 2024 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 2025 | Hawthorne Oil And Gas Corp. | Houston, TX 77227 | Oil & Gas Operator | Sep 1993 |
| 2026 | Hawthorne-Tipco | | Oil & Gas Operator | Oct 1978 |
| 2027 | HC Resources, Inc. | | Oil & Gas Operator | Jul 2011 |
| 2028 | HCW Exploration, Inc. | | Oil & Gas Operator | Jun 1986 |
| 2029 | HDS Production | | Oil Operator | Mar 1998 |
| 2030 | Headington Energy Corporation | Dallas, TX 75231 | Oil & Gas Operator | Aug 1992 |
| 2031 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 2032 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 2033 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 2034 | Headwaters Oil Company | | Oil & Gas Operator | Oct 1981 |
| 2035 | Hebert & Rucks L.L.C. | | Oil & Gas Operator | May 2002 |
| 2036 | Hec Petroleum, Inc | Midland, TX 79705 | Oil & Gas Operator | Mar 2006 |
| 2037 | Held By Production, Inc. | Houston, TX 77251 | Oil & Gas Operator | May 1996 |
| 2038 | Helena Production Corp | | Oil & Gas Operator | Dec 1991 |
| 2039 | Helis Oil & Gas Company, L.L.C. | New Orleans, LA 70130 | Oil & Gas Operator | Oct 2023 |
| 2040 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jan 2025 |
| 2041 | Hemco Development, LLC | Dallas, TX 75201 | Oil & Gas Operator | Nov 2020 |
| 2042 | Hemus, Inc. | Bellaire, TX 77401 | Oil & Gas Operator | Sep 1994 |
| 2043 | Henderson Oil & Gas | | Oil Operator | Sep 1990 |
| 2044 | Henderson Pet Corp Of Delaware | | Oil & Gas Operator | Oct 2019 |
| 2045 | Henderson Petroleum Corp | San Angelo, TX 76906 | Oil & Gas Operator | Jul 2013 |
| 2046 | Henergy Oil & Gas LLC | | Oil Operator | Jan 2025 |
| 2047 | Henry Production Company, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Oct 2019 |
| 2048 | Hep Oil GP, LLC | Gainesville, TX 76241 | Oil & Gas Operator | Mar 2015 |
| 2049 | Herbert J. Schmitz | | Oil & Gas Operator | Dec 1987 |
| 2050 | Herbst Resources, Inc. | Mandeville, LA 70448 | Oil & Gas Operator | Aug 2003 |
| 2051 | Herd Producing Company, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Apr 2025 |
| 2052 | Heritage Energy Company | | Oil & Gas Operator | Jun 2001 |
| 2053 | Heritage Operating Co., Inc. The | Stafford, TX 77497 | Oil & Gas Operator | May 1997 |
| 2054 | Herlin Et Al | | Oil & Gas Operator | Mar 1985 |
| 2055 | Herman Fields | | Oil & Gas Operator | May 1989 |
| 2056 | Herring Production Co | | Oil & Gas Operator | Mar 1992 |
| 2057 | Hess Corporation, A De Corp. | | Oil & Gas Operator | Oct 2006 |
| 2058 | Hexagon Oil And Gas Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | Apr 2025 |
| 2059 | HGH Energy, Inc. | | Oil & Gas Operator | Jun 2001 |
| 2060 | Hibbard-Frost-Smith | | Oil & Gas Operator | Apr 1990 |
| 2061 | Hicks Production Co. | | Oil & Gas Operator | Apr 1991 |
| 2062 | High-Hope Oil And Gas, Inc | | Oil & Gas Operator | Mar 2017 |
| 2063 | Highland Minerals, Inc. | Tulsa, OK 74145-7627 | Oil & Gas Operator | Apr 2015 |
| 2064 | Highland Resources, Inc. | | Oil & Gas Operator | Dec 2004 |
| 2065 | Highlander Oil & Gas Assets LLC | | Gas Operator | Jan 2025 |
| 2066 | Highlands Operating Co., Inc. | | Oil & Gas Operator | May 1990 |
| 2067 | Highmark Energy Operating, LLC | Dallas, TX 75222 | Oil & Gas Operator | Apr 2025 |
| 2068 | Hilburn Ind., Inc. | | Oil Operator | Jan 1978 |
| 2069 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Apr 2025 |
| 2070 | Hill Production | | Oil & Gas Operator | Nov 1981 |
| 2071 | Hill Production Co Inc-Wisconsin | Humble, TX 77347 | Oil & Gas Operator | Jun 1993 |
| 2072 | Hilliard Oil & Gas Inc | New Orleans, LA 70112 | Oil & Gas Operator | May 2001 |
| 2073 | Hilliard Petroleum Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Sep 2009 |
| 2074 | Hillside Oil & Gas, LLC | Midland, TX 79708 | Oil & Gas Operator | Apr 2016 |
| 2075 | Hilty Interests, Inc. | Kerrville, TX 78028 | Oil & Gas Operator | Jun 1989 |
| 2076 | Hinton Well Servicing, Inc. | | Oil Operator | Feb 2008 |
| 2077 | Hispanic Oil & Gas Energy LLC | | Oil Operator | Jan 2025 |
| 2078 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 2079 | Hobbs Oil Co. | | Oil Operator | Dec 1999 |
| 2080 | Hobbs Production LLC | | Oil Operator | Mar 2023 |
| 2081 | Hochendel Consultants | | Oil & Gas Operator | Jul 1995 |
| 2082 | Hogan Drilling Company, Inc. | | Oil & Gas Operator | Mar 1981 |
| 2083 | Hogan Energy Corporation | | Oil & Gas Operator | Oct 1999 |
| 2084 | Hogan Exploration, Inc. | | Oil & Gas Operator | Mar 2000 |
| 2085 | Holden Energy Corporation | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2015 |
| 2086 | Holland Production Co | | Oil Operator | Aug 1982 |
| 2087 | Holleman & Parks Oil & Gas Inc | | Oil & Gas Operator | May 1995 |
| 2088 | Hollenshead Oil Co. | | Oil & Gas Operator | Mar 1992 |
| 2089 | Holston-GR. Sou. Oil & Gas Co. | | Oil & Gas Operator | Mar 1981 |
| 2090 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Apr 2025 |
| 2091 | Homer D. Oliver | | Gas Operator | Sep 1998 |
| 2092 | Homer E. Hines, Inc. | | Oil Operator | Sep 1978 |
| 2093 | Hondo Operating, Inc. | | Oil & Gas Operator | Aug 1997 |
| 2094 | Hootkins-Smith,La LTD. | | Gas Operator | Jun 1985 |
| 2095 | Hope Oil Inc | Midland, TX 79702 | Oil & Gas Operator | Oct 2021 |
| 2096 | Horizon Expl. & Dev. Co., Inc. | | Oil & Gas Operator | Jun 1995 |
| 2097 | Horton & Freeman | | Oil Operator | Apr 1983 |
| 2098 | Hosston Oil Inc. | | Oil Operator | Dec 1993 |
| 2099 | Hou-Tex Oil And Gas | | Oil & Gas Operator | Jul 1982 |
| 2100 | Hou-Tex, Inc. | Houston, TX 77224 | Oil & Gas Operator | Jun 2001 |