| 1901 | Enersource Royalty Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2013 |
| 1902 | Enertec Corporation | Nowata, OK 74048-0632 | Oil & Gas Operator | Sep 2018 |
| 1903 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | May 2026 |
| 1904 | Enex Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 1905 | Enexco, Inc. | Dallas, TX 75243 | Oil & Gas Operator | Mar 2017 |
| 1906 | England Operating LLC | Littleton, CO 80120-4529 | Oil & Gas Operator | Nov 2014 |
| 1907 | Enhanced Hydrocarbons Inc | Claremore, OK 74017 | Oil & Gas Operator | May 2013 |
| 1908 | Enloe Jenny L | Skiatook, OK 74070 | Oil Operator | Nov 1998 |
| 1909 | Enmark Gas Gathering LP | Dallas, TX 75252 | Oil & Gas Operator | Dec 2025 |
| 1910 | Ennex Inc | | Oil & Gas Operator | Oct 1993 |
| 1911 | Ennis Bill H | Sasakwa, OK 74867-0001 | Oil & Gas Operator | Sep 2014 |
| 1912 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 1913 | Ensight Energy Group Inc | Richardson, TX 75080-2370 | Oil & Gas Operator | Jan 2026 |
| 1914 | Ensource Inc | Midland, TX 79705 | Oil & Gas Operator | Aug 1998 |
| 1915 | Enterprise Energy Exploration Inc | Tulsa, OK 74133-6724 | Oil & Gas Operator | Feb 2026 |
| 1916 | Enterprise Energy Prod Co Inc | Tulsa, OK 74133-6754 | Oil & Gas Operator | Mar 2015 |
| 1917 | Enterprise Exploration Inc | Tulsa, OK 74133 | Oil & Gas Operator | Nov 2020 |
| 1918 | Enterprising Enterprises Inc | Tulsa, OK 74137 | Oil Operator | Jun 2009 |
| 1919 | Entex Petroleum Inc | Oklahoma City, OK 73113 | Oil & Gas Operator | Nov 1997 |
| 1920 | Entransco Energy LLC | Dewey, OK 74029 | Oil & Gas Operator | Oct 2024 |
| 1921 | Envirotek Fuel Systems Inc | Dallas, TX 75243 | Oil & Gas Operator | May 2013 |
| 1922 | EOG (Oklahoma) Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Oct 2016 |
| 1923 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | May 2026 |
| 1924 | Eok Operating LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Jan 2026 |
| 1925 | Eott Energy Operating LP | Houston, TX 77210-4666 | Oil & Gas Operator | Oct 2009 |
| 1926 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 1927 | EP Operating LP | Dallas, TX 75201 | Oil & Gas Operator | Mar 2015 |
| 1928 | Epley Bobbie Inc | Wilson, OK 73463-6319 | Oil Operator | Jun 2007 |
| 1929 | Epoch Resources Of Texas Inc | Port Aransas, TX 78373-1637 | Oil & Gas Operator | Nov 2014 |
| 1930 | Epperson Dwight | Okemah, OK 74859 | Oil Operator | Jan 2013 |
| 1931 | Epperson John R | Bartlesville, OK 74003 | Oil Operator | Aug 1999 |
| 1932 | Equal Energy Us Inc | Tulsa, OK 74103-4621 | Oil & Gas Operator | Nov 2019 |
| 1933 | Equinox Oil Company Inc | Plainville, KS 67663 | Oil & Gas Operator | Dec 2019 |
| 1934 | Equipment Lott Inc The | Hennessey, OK 73742-0655 | Oil & Gas Operator | Mar 2008 |
| 1935 | Equity Drilling Company Inc | Dewey, OK 74029 | Oil & Gas Operator | Nov 1998 |
| 1936 | Eratz Investments Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2026 |
| 1937 | Ernst Petroleum Company Inc | Arlington, VA 22201 | Oil & Gas Operator | Aug 2013 |
| 1938 | Erwin, James D. | Dallas, TX 75225 | Oil & Gas Operator | Nov 1993 |
| 1939 | Erwin, Sanford P | | Oil & Gas Operator | Apr 2019 |
| 1940 | Escher Corporation | Oklahoma City, OK 73120 | Oil & Gas Operator | Aug 2025 |
| 1941 | Esco Exploration, Inc | Dallas, TX 75201 | Oil & Gas Operator | Mar 2015 |
| 1942 | Escott Oil Inc | Nowata, OK 74048 | Oil & Gas Operator | Feb 2000 |
| 1943 | Esenjay Exploration, Inc | Houston, TX 77042 | Oil & Gas Operator | Jan 2026 |
| 1944 | Esis Inc | | Oil & Gas Operator | Feb 2017 |
| 1945 | Eskridge Oil & Supply | Tulsa, OK 74105 | Oil Operator | Aug 2014 |
| 1946 | Eskridge Production Company | Tulsa, OK 74112-1428 | Oil Operator | Sep 2019 |
| 1947 | Eslick Nancy Sue | Bristow, OK 74010-3873 | Oil Operator | Aug 2013 |
| 1948 | Esper Production Co | Arlington, TX 76011-2427 | Oil & Gas Operator | Apr 2015 |
| 1949 | Esperanza Energy Corp. | Prosper, TX 75078 | Oil & Gas Operator | Mar 2015 |
| 1950 | Essex Energy Inc | Yukon, OK 73099-5126 | Oil & Gas Operator | Apr 2014 |
| 1951 | Essman Energy, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2019 |
| 1952 | Estate Oil & Gas LLC | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2026 |
| 1953 | Estoril Producing Corporation | Midland, TX 79701 | Oil & Gas Operator | Apr 1994 |
| 1954 | Eubank Michael Dba Trilby Oil Company | Amber, OK 73004-4903 | Oil Operator | May 2022 |
| 1955 | Eubank Operating Company | Cushing, OK 74023 | Oil & Gas Operator | Aug 2024 |
| 1956 | Evans Production Co. | Pampa, TX 79066 | Oil & Gas Operator | Sep 2020 |
| 1957 | Evergreen Operating Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2019 |
| 1958 | Evolution Energy LLC | Oklahoma City, OK 73116 | Oil & Gas Operator | Feb 2026 |
| 1959 | Evolution Operating Co., Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2026 |
| 1960 | Ew Carter Oil Co;Inc | | Oil & Gas Operator | Feb 2026 |
| 1961 | Ewsc Inc | Kenosha, WI 53142-3775 | Oil & Gas Operator | Apr 2020 |
| 1962 | Excalibur Resources LLC | Houston, TX 77002-5220 | Oil & Gas Operator | Feb 2026 |
| 1963 | Excel Operating Inc | Dallas, TX 75234-7300 | Oil & Gas Operator | Jun 2022 |
| 1964 | Excel Production Inc | Lubbock, TX 79424-2341 | Oil Operator | Apr 2020 |
| 1965 | Excelco Energy Inc. | Kingwood, TX 77339 | Oil & Gas Operator | Jul 2018 |
| 1966 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Jan 2026 |
| 1967 | Exok Inc | Oklahoma City, OK 73116 | Oil & Gas Operator | Jan 2026 |
| 1968 | Exoko Operating Company Inc | Tulsa, OK 74170-0246 | Oil & Gas Operator | Jan 2006 |
| 1969 | Explo Oil, Inc. | Dallas, TX 75251 | Oil & Gas Operator | May 2026 |
| 1970 | Exploration Associates | Oklahoma City, OK 73102-8606 | Oil & Gas Operator | Mar 2015 |
| 1971 | Exploration Associates II LLC | Oklahoma City, OK 73102-8815 | Oil & Gas Operator | Jan 2013 |
| 1972 | Exploration Professionals Inc | Chelsea, OK 74016-0066 | Oil Operator | Dec 2023 |
| 1973 | Exploration Technologies Inc | Crescent, OK 73028-0546 | Oil & Gas Operator | Mar 2015 |
| 1974 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | May 2026 |
| 1975 | Express Oil & Gas LLC | Oklahoma City, OK 73142-3017 | Oil & Gas Operator | Feb 2026 |
| 1976 | Extex Operating Company | Houston, TX 77057 | Oil & Gas Operator | May 2026 |
| 1977 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | May 2026 |
| 1978 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | Jan 2026 |
| 1979 | Eyler Corporation | | Oil & Gas Operator | Nov 2012 |
| 1980 | Eyler Dean E | Cleveland, OK 74020 | Oil & Gas Operator | Jan 2026 |
| 1981 | Eyler Nelson E | | Oil Operator | Nov 1998 |
| 1982 | Ezekiel Exploration, LLC | Blanchard, OK 73010 | Oil & Gas Operator | Jan 2026 |
| 1983 | F & G Management LLC | Claremore, OK 74019-0392 | Oil Operator | Feb 2026 |
| 1984 | F & J Oil Company, L.L.C. | | Oil Operator | Jan 2026 |
| 1985 | F & M Oil Company Inc | Pettus, TX 78146 | Oil & Gas Operator | May 2026 |
| 1986 | F & S Energy LLC | Crescent, OK 73028 | Oil & Gas Operator | Feb 2026 |
| 1987 | F C D Oil Corporation | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 1995 |
| 1988 | F D & Jack Oil Company | Muskogee, OK 74402-1444 | Oil & Gas Operator | May 2015 |
| 1989 | F Davis Oil & Gas LLC | Cleveland, OK 74020 | Oil Operator | Feb 2026 |
| 1990 | F M Hoel | | Oil & Gas Operator | Dec 2000 |
| 1991 | F O & G LLC | Pawhuska, OK 74056-5075 | Oil Operator | Apr 2022 |
| 1992 | F P C Disposal Inc | El Reno, OK 73036-5501 | Oil Operator | Apr 2003 |
| 1993 | Fackrell & Associates LLC | Ardmore, OK 73402-1452 | Oil Operator | Aug 2025 |
| 1994 | Fadem Oil Company | Tulsa, OK 74135 | Oil Operator | Jan 1996 |
| 1995 | Fagan Engineering | Shawnee, OK 74801-3021 | Oil & Gas Operator | Oct 1994 |
| 1996 | Fahrenheit Petroleum Co Inc | | Oil & Gas Operator | Mar 2015 |
| 1997 | Fail W T Inc | | Oil & Gas Operator | Mar 2015 |
| 1998 | Fair Oil Company | Tyler, TX 75710 | Oil & Gas Operator | Dec 2000 |
| 1999 | Fairchild Oil Corporation | Edmond, OK 73013 | Oil & Gas Operator | Oct 1994 |
| 2000 | Fairchild Well Service Inc | Ponca City, OK 74602-0470 | Oil & Gas Operator | Jun 2006 |