| 1901 | Elk Oil Company | Overland Park, KS 66212 | Oil & Gas Operator | Sep 2007 |
| 1902 | Elkhorn Exploration Co | Willis, TX 77378-8827 | Oil & Gas Operator | Dec 2025 |
| 1903 | Ellard I W | Bixby, OK 74008-0220 | Oil & Gas Operator | Jan 2007 |
| 1904 | Elliott Resources Inc | Ada, OK 74820-9227 | Oil & Gas Operator | Jul 2010 |
| 1905 | Ellis Resources Group Inc | Rhinelander, WI 54501 | Oil Operator | Aug 2025 |
| 1906 | Ellis Rolland | Henryetta, OK 74437-0536 | Oil & Gas Operator | Sep 2018 |
| 1907 | Ellithorp Production LLC | Lindsay, OK 73052-5013 | Oil & Gas Operator | Apr 2019 |
| 1908 | Ells Jr Harry A | Englewood, CO 80150 | Gas Operator | Feb 2017 |
| 1909 | Elm Ridge Exploration Company LLC | Bloomfield, NM 87413 | Oil & Gas Operator | Nov 2017 |
| 1910 | Elmore Stanley G | Bartlesville, OK 74006-1741 | Oil & Gas Operator | Sep 2023 |
| 1911 | Elmtree Oil Co Inc | Bartlesville, OK 74006-1819 | Oil Operator | May 2021 |
| 1912 | Elson Oil Company | Tulsa, OK 74103-4429 | Oil & Gas Operator | Dec 2016 |
| 1913 | Elvera Stiles Trust | Broken Arrow, OK 74011 | Oil & Gas Operator | Apr 2025 |
| 1914 | Emc Exploration Company Inc | Oklahoma City, OK 73103-3775 | Oil & Gas Operator | Jul 2007 |
| 1915 | Emde & McNeil | Carney, OK 74832 | Oil & Gas Operator | Nov 1998 |
| 1916 | Emerald Operating Company | Plano, TX 75075 | Oil & Gas Operator | Nov 2025 |
| 1917 | Emerson Oil Company | Rindge, NH 03461 | Oil & Gas Operator | Feb 2008 |
| 1918 | Emery Billie E | Skiatook, OK 74070 | Oil Operator | Oct 2025 |
| 1919 | Emery Edward A | Tulsa, OK 74145-7921 | Oil Operator | Oct 2025 |
| 1920 | Emjo Operations Inc | Marlow, OK 73055-8803 | Oil & Gas Operator | Nov 2025 |
| 1921 | Emo Inc | Eufaula, OK 74432-0841 | Oil & Gas Operator | Apr 2020 |
| 1922 | Empire Land Corporation | New Orleans, LA 70130 | Oil & Gas Operator | Nov 2014 |
| 1923 | Empire Petroleum Company | Houston, TX 77044 | Oil Operator | Mar 2011 |
| 1924 | Empire Petroleum LLC | Salt Lake City, UT 84121-7021 | Oil & Gas Operator | Jun 2019 |
| 1925 | Enable Gas Transmission LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2022 |
| 1926 | Enable Oklahoma Intrastate Transmission LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2022 |
| 1927 | Encana Energy Resources Inc | Denver, CO 80202-2828 | Oil & Gas Operator | Feb 2024 |
| 1928 | Encino Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Dec 2025 |
| 1929 | Encore Operating Inc | Edmond, OK 73013-5417 | Oil Operator | Oct 2025 |
| 1930 | Encore Operating LP | Plano, TX 75024 | Oil & Gas Operator | Nov 2025 |
| 1931 | Endeavor Drilling, Inc. | Wagoner, OK 74467 | Oil Operator | Oct 2025 |
| 1932 | Endeavor Energy Resources, LP | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 1933 | Endeavor Natural Gas, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2015 |
| 1934 | Endevco Eureka LLC | Oklahoma City, OK 73102-9211 | Oil & Gas Operator | Apr 2014 |
| 1935 | Endicott Melvin F | Ponca City, OK 74601 | Oil & Gas Operator | Apr 2001 |
| 1936 | Enerco Energy Corporation | Norman, OK 73069-6643 | Oil & Gas Operator | Apr 2020 |
| 1937 | Enerfin Gathering-East LLC | Houston, TX 77077 | Oil & Gas Operator | Nov 2022 |
| 1938 | Enerfin Resources I Limited Partnership | Houston, TX 77077-2386 | Oil & Gas Operator | Apr 2023 |
| 1939 | Energas Corporation | Oklahoma City, OK 73105 | Oil & Gas Operator | Jul 2025 |
| 1940 | Energex Corp | Springfield, MO 65807 | Oil & Gas Operator | Oct 2025 |
| 1941 | Energex Inc. | Abilene, TX 79604 | Oil & Gas Operator | Dec 2025 |
| 1942 | Energon Oil, Inc. | Amarillo, TX 79114 | Oil & Gas Operator | Dec 2025 |
| 1943 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2024 |
| 1944 | Energy Environment Inc | Holdenville, OK 74848-0765 | Oil & Gas Operator | Jul 2016 |
| 1945 | Energy Exchange Corporation | Oklahoma City, OK 73112 | Oil Operator | Oct 2025 |
| 1946 | Energy Group Of America, Inc. | Hollister, MO 65672 | Oil Operator | Dec 2025 |
| 1947 | Energy Lease Service Inc | Drumright, OK 74030-7403 | Oil & Gas Operator | Oct 2025 |
| 1948 | Energy Operating Corporation | Plano, TX 75093-4409 | Oil & Gas Operator | Sep 2013 |
| 1949 | Energy Operations Oklahoma LP | Houston, TX 77002-6785 | Oil & Gas Operator | Nov 2010 |
| 1950 | Energy Production Services LLC | Oklahoma City, OK 73162-4736 | Oil & Gas Operator | Apr 2020 |
| 1951 | Energy Resources Dev Inc | Bixby, OK 74008-3658 | Oil & Gas Operator | Oct 2025 |
| 1952 | Energy Support Services LLC | Cheyenne, WY 82001 | Oil & Gas Operator | Jan 2025 |
| 1953 | Energy Three Inc. | Jackson, MS 39211 | Oil & Gas Operator | Sep 2025 |
| 1954 | Energy Transfer Crude Marketing LLC | Dallas, TX 75225 | Oil Operator | Oct 2025 |
| 1955 | Energyquest II, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Oct 2025 |
| 1956 | Energyquest Management, LLC | Houston, TX 77090 | Oil & Gas Operator | Apr 2021 |
| 1957 | Enernet Inc | Oklahoma City, OK 73102-8004 | Oil & Gas Operator | Nov 2014 |
| 1958 | Enerquest Oil & Gas LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Oct 2025 |
| 1959 | Enersearch Inc | Sand Springs, OK 74063 | Oil & Gas Operator | Dec 2013 |
| 1960 | Enersource Petroleum Inc | Bixby, OK 74008 | Oil & Gas Operator | Oct 2025 |
| 1961 | Enersource Royalty Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2013 |
| 1962 | Enertec Corporation | Nowata, OK 74048-0632 | Oil & Gas Operator | Sep 2018 |
| 1963 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 1964 | Enex Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 1965 | Enexco, Inc. | Dallas, TX 75243 | Oil & Gas Operator | Mar 2017 |
| 1966 | England Operating LLC | Littleton, CO 80120-4529 | Oil & Gas Operator | Nov 2014 |
| 1967 | Enhanced Hydrocarbons Inc | Claremore, OK 74017 | Oil & Gas Operator | May 2013 |
| 1968 | Enloe Jenny L | Skiatook, OK 74070 | Oil Operator | Nov 1998 |
| 1969 | Enmark Gas Gathering LP | Dallas, TX 75252 | Oil & Gas Operator | Sep 2025 |
| 1970 | Ennex Inc | | Oil & Gas Operator | Oct 1993 |
| 1971 | Ennis Bill H | Sasakwa, OK 74867-0001 | Oil & Gas Operator | Sep 2014 |
| 1972 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 1973 | Ensight Energy Group Inc | Richardson, TX 75080-2370 | Oil & Gas Operator | Oct 2025 |
| 1974 | Ensource Inc | Midland, TX 79705 | Oil & Gas Operator | Aug 1998 |
| 1975 | Enterprise Energy Exploration Inc | Tulsa, OK 74133-6724 | Oil & Gas Operator | Oct 2025 |
| 1976 | Enterprise Energy Prod Co Inc | Tulsa, OK 74133-6754 | Oil & Gas Operator | Mar 2015 |
| 1977 | Enterprise Exploration Inc | Tulsa, OK 74133 | Oil & Gas Operator | Nov 2020 |
| 1978 | Enterprising Enterprises Inc | Tulsa, OK 74137 | Oil Operator | Jun 2009 |
| 1979 | Entex Petroleum Inc | Oklahoma City, OK 73113 | Oil & Gas Operator | Nov 1997 |
| 1980 | Entransco Energy LLC | Dewey, OK 74029 | Oil & Gas Operator | Oct 2024 |
| 1981 | Envirotek Fuel Systems Inc | Dallas, TX 75243 | Oil & Gas Operator | May 2013 |
| 1982 | EOG (Oklahoma) Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Oct 2016 |
| 1983 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 1984 | Eok Operating LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Nov 2025 |
| 1985 | Eott Energy Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 1995 |
| 1986 | Eott Energy Operating LP | Houston, TX 77210-4666 | Oil & Gas Operator | Oct 2009 |
| 1987 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 1988 | EP Operating LP | Dallas, TX 75201 | Oil & Gas Operator | Mar 2015 |
| 1989 | Epley Bobbie Inc | Wilson, OK 73463-6319 | Oil Operator | Jun 2007 |
| 1990 | Epoch Resources Of Texas Inc | Port Aransas, TX 78373-1637 | Oil & Gas Operator | Nov 2014 |
| 1991 | Epperson Dwight | Okemah, OK 74859 | Oil Operator | Jan 2013 |
| 1992 | Epperson John R | Bartlesville, OK 74003 | Oil Operator | Aug 1999 |
| 1993 | Equal Energy Us Inc | Tulsa, OK 74103-4621 | Oil & Gas Operator | Nov 2019 |
| 1994 | Equinox Oil Company Inc | Plainville, KS 67663 | Oil & Gas Operator | Dec 2019 |
| 1995 | Equipment Lott Inc The | Hennessey, OK 73742-0655 | Oil & Gas Operator | Mar 2008 |
| 1996 | Equity Drilling Company Inc | Dewey, OK 74029 | Oil & Gas Operator | Nov 1998 |
| 1997 | Equity Export Oil & Gas Co Inc | Kansas City, MO 64116 | Oil & Gas Operator | Feb 2002 |
| 1998 | Eratz Investments Inc. | Dallas, TX 75240 | Oil & Gas Operator | Dec 2025 |
| 1999 | Ernst Petroleum Company Inc | Arlington, VA 22201 | Oil & Gas Operator | Aug 2013 |
| 2000 | Erwin, James D. | Dallas, TX 75225 | Oil & Gas Operator | Nov 1993 |