| 1901 | Endicott Melvin F | Ponca City, OK 74601 | Oil & Gas Operator | Apr 2001 |
| 1902 | Enerco Energy Corporation | Norman, OK 73069-6643 | Oil & Gas Operator | Apr 2020 |
| 1903 | Enerfin Gathering-East LLC | Houston, TX 77077 | Oil & Gas Operator | Nov 2022 |
| 1904 | Enerfin Resources I Limited Partnership | Houston, TX 77077-2386 | Oil & Gas Operator | Apr 2023 |
| 1905 | Energas Corporation | Oklahoma City, OK 73105 | Oil & Gas Operator | Jul 2025 |
| 1906 | Energex Corp | Springfield, MO 65807 | Oil & Gas Operator | Apr 2026 |
| 1907 | Energex Inc. | Abilene, TX 79604 | Oil & Gas Operator | Jul 2026 |
| 1908 | Energon Oil, Inc. | Amarillo, TX 79114 | Oil & Gas Operator | Jul 2026 |
| 1909 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2025 |
| 1910 | Energy Environment Inc | Holdenville, OK 74848-0765 | Oil & Gas Operator | Jul 2016 |
| 1911 | Energy Exchange Corporation | Oklahoma City, OK 73112 | Oil Operator | Apr 2026 |
| 1912 | Energy Group Of America, Inc. | Hollister, MO 65672 | Oil Operator | Jul 2026 |
| 1913 | Energy Lease Service Inc | Drumright, OK 74030-7403 | Oil & Gas Operator | Apr 2026 |
| 1914 | Energy Operating Corporation | Plano, TX 75093-4409 | Oil & Gas Operator | Sep 2013 |
| 1915 | Energy Operations Oklahoma LP | Houston, TX 77002-6785 | Oil & Gas Operator | Nov 2010 |
| 1916 | Energy Production Services LLC | Oklahoma City, OK 73162-4736 | Oil & Gas Operator | Apr 2020 |
| 1917 | Energy Resources Dev Inc | Bixby, OK 74008-3658 | Oil & Gas Operator | Apr 2026 |
| 1918 | Energy Support Services LLC | Cheyenne, WY 82001 | Oil & Gas Operator | Jan 2025 |
| 1919 | Energy Three Inc. | Jackson, MS 39211 | Oil & Gas Operator | Mar 2026 |
| 1920 | Energy Transfer Crude Marketing LLC | Dallas, TX 75225 | Oil Operator | Apr 2026 |
| 1921 | Energyquest II, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Apr 2026 |
| 1922 | Energyquest Management, LLC | Houston, TX 77090 | Oil & Gas Operator | Apr 2021 |
| 1923 | Enernet Inc | Oklahoma City, OK 73102-8004 | Oil & Gas Operator | Nov 2014 |
| 1924 | Enerquest Oil & Gas LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Apr 2026 |
| 1925 | Enersearch Inc | Sand Springs, OK 74063 | Oil & Gas Operator | Dec 2013 |
| 1926 | Enersource Petroleum Inc | Bixby, OK 74008 | Oil & Gas Operator | Apr 2026 |
| 1927 | Enersource Royalty Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2013 |
| 1928 | Enertec Corporation | Nowata, OK 74048-0632 | Oil & Gas Operator | Sep 2018 |
| 1929 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2026 |
| 1930 | Enex Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 1931 | Enexco, Inc. | Dallas, TX 75243 | Oil & Gas Operator | Mar 2017 |
| 1932 | England Operating LLC | Littleton, CO 80120-4529 | Oil & Gas Operator | Nov 2014 |
| 1933 | Enhanced Hydrocarbons Inc | Claremore, OK 74017 | Oil & Gas Operator | May 2013 |
| 1934 | Enloe Jenny L | Skiatook, OK 74070 | Oil Operator | Nov 1998 |
| 1935 | Enmark Gas Gathering LP | Dallas, TX 75252 | Oil & Gas Operator | Mar 2026 |
| 1936 | Ennex Inc | | Oil & Gas Operator | Oct 1993 |
| 1937 | Ennis Bill H | Sasakwa, OK 74867-0001 | Oil & Gas Operator | Sep 2014 |
| 1938 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 1939 | Ensight Energy Group Inc | Richardson, TX 75080-2370 | Oil & Gas Operator | Apr 2026 |
| 1940 | Ensource Inc | Midland, TX 79705 | Oil & Gas Operator | Aug 1998 |
| 1941 | Enterprise Energy Exploration Inc | Tulsa, OK 74133-6724 | Oil & Gas Operator | May 2026 |
| 1942 | Enterprise Energy Prod Co Inc | Tulsa, OK 74133-6754 | Oil & Gas Operator | Mar 2015 |
| 1943 | Enterprise Exploration Inc | Tulsa, OK 74133 | Oil & Gas Operator | Nov 2020 |
| 1944 | Enterprising Enterprises Inc | Tulsa, OK 74137 | Oil Operator | Jun 2009 |
| 1945 | Entex Petroleum Inc | Oklahoma City, OK 73113 | Oil & Gas Operator | Nov 1997 |
| 1946 | Entransco Energy LLC | Dewey, OK 74029 | Oil & Gas Operator | Oct 2024 |
| 1947 | Envirotek Fuel Systems Inc | Dallas, TX 75243 | Oil & Gas Operator | May 2013 |
| 1948 | EOG (Oklahoma) Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Oct 2016 |
| 1949 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 1950 | Eok Operating LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | May 2026 |
| 1951 | Eott Energy Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 1995 |
| 1952 | Eott Energy Operating LP | Houston, TX 77210-4666 | Oil & Gas Operator | Oct 2009 |
| 1953 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 1954 | EP Operating LP | Dallas, TX 75201 | Oil & Gas Operator | Mar 2015 |
| 1955 | Epley Bobbie Inc | Wilson, OK 73463-6319 | Oil Operator | Jun 2007 |
| 1956 | Epoch Resources Of Texas Inc | Port Aransas, TX 78373-1637 | Oil & Gas Operator | Nov 2014 |
| 1957 | Epperson Dwight | Okemah, OK 74859 | Oil Operator | Jan 2013 |
| 1958 | Epperson John R | Bartlesville, OK 74003 | Oil Operator | Aug 1999 |
| 1959 | Equal Energy Us Inc | Tulsa, OK 74103-4621 | Oil & Gas Operator | Nov 2019 |
| 1960 | Equinox Oil Company Inc | Plainville, KS 67663 | Oil & Gas Operator | Dec 2019 |
| 1961 | Equipment Lott Inc The | Hennessey, OK 73742-0655 | Oil & Gas Operator | Mar 2008 |
| 1962 | Equity Drilling Company Inc | Dewey, OK 74029 | Oil & Gas Operator | Nov 1998 |
| 1963 | Equity Export Oil & Gas Co Inc | Kansas City, MO 64116 | Oil & Gas Operator | Feb 2002 |
| 1964 | Eratz Investments Inc. | Dallas, TX 75240 | Oil & Gas Operator | Jul 2026 |
| 1965 | Ernst Petroleum Company Inc | Arlington, VA 22201 | Oil & Gas Operator | Aug 2013 |
| 1966 | Erwin, James D. | Dallas, TX 75225 | Oil & Gas Operator | Nov 1993 |
| 1967 | Erwin, Sanford P | | Oil & Gas Operator | Apr 2019 |
| 1968 | Escher Corporation | Oklahoma City, OK 73120 | Oil & Gas Operator | Mar 2026 |
| 1969 | Esco Exploration, Inc | Dallas, TX 75201 | Oil & Gas Operator | Mar 2015 |
| 1970 | Escott Oil Inc | Nowata, OK 74048 | Oil & Gas Operator | Feb 2000 |
| 1971 | Esenjay Exploration, Inc | Houston, TX 77042 | Oil & Gas Operator | Mar 2026 |
| 1972 | Esis Inc | | Oil & Gas Operator | Feb 2017 |
| 1973 | Eskridge Oil & Supply | Tulsa, OK 74105 | Oil Operator | Aug 2014 |
| 1974 | Eskridge Production Company | Tulsa, OK 74112-1428 | Oil Operator | Sep 2019 |
| 1975 | Eslick Nancy Sue | Bristow, OK 74010-3873 | Oil Operator | Aug 2013 |
| 1976 | Esper Production Co | Arlington, TX 76011-2427 | Oil & Gas Operator | Apr 2015 |
| 1977 | Esperanza Energy Corp. | Prosper, TX 75078 | Oil & Gas Operator | Mar 2015 |
| 1978 | Essex Energy Inc | Yukon, OK 73099-5126 | Oil & Gas Operator | Apr 2014 |
| 1979 | Essman Energy, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2019 |
| 1980 | Estoril Producing Corporation | Midland, TX 79701 | Oil & Gas Operator | Apr 1994 |
| 1981 | Eubank Michael Dba Trilby Oil Company | Amber, OK 73004-4903 | Oil Operator | May 2022 |
| 1982 | Eubank Operating Company | Cushing, OK 74023 | Oil & Gas Operator | Aug 2024 |
| 1983 | Evans Production Co. | Pampa, TX 79066 | Oil & Gas Operator | Sep 2020 |
| 1984 | Evergreen Operating Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2019 |
| 1985 | Evolution Energy LLC | Oklahoma City, OK 73116 | Oil & Gas Operator | May 2026 |
| 1986 | Evolution Operating Co., Inc. | Houston, TX 77079 | Oil & Gas Operator | Jul 2026 |
| 1987 | Ew Carter Oil Co;Inc | | Oil & Gas Operator | Apr 2026 |
| 1988 | Ew Operating (Ok), LLC | Fayetteville, AR 72703 | Gas Operator | May 2026 |
| 1989 | Ewsc Inc | Kenosha, WI 53142-3775 | Oil & Gas Operator | Apr 2020 |
| 1990 | Excalibur Resources LLC | Houston, TX 77002-5220 | Oil & Gas Operator | Apr 2026 |
| 1991 | Excel Operating Inc | Dallas, TX 75234-7300 | Oil & Gas Operator | Jun 2022 |
| 1992 | Excel Production Inc | Lubbock, TX 79424-2341 | Oil Operator | Apr 2020 |
| 1993 | Excelco Energy Inc. | Kingwood, TX 77339 | Oil & Gas Operator | Jul 2018 |
| 1994 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Apr 2026 |
| 1995 | Exok Inc | Oklahoma City, OK 73116 | Oil & Gas Operator | Apr 2026 |
| 1996 | Exoko Operating Company Inc | Tulsa, OK 74170-0246 | Oil & Gas Operator | Jan 2006 |
| 1997 | Explo Oil, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Jul 2026 |
| 1998 | Exploration Associates | Oklahoma City, OK 73102-8606 | Oil & Gas Operator | Mar 2015 |
| 1999 | Exploration Associates II LLC | Oklahoma City, OK 73102-8815 | Oil & Gas Operator | Jan 2013 |
| 2000 | Exploration Professionals Inc | Chelsea, OK 74016-0066 | Oil Operator | Dec 2023 |