| 801 | Devonian Resources Inc | Pikeville, KY 41502 | Oil & Gas Operator | Dec 2024 |
| 802 | Devore Anthony D | Gambier, OH 43022 | Oil & Gas Operator | Dec 2010 |
| 803 | Devx Operating Company | Frisco, TX 75034 | Oil & Gas Operator | Feb 2004 |
| 804 | Dew Oil And Gas Co.,Inc. | | Oil & Gas Operator | Dec 1989 |
| 805 | Dewayne'S Tank Service, Inc. | Saint John, KS 67576 | Oil Operator | Nov 2000 |
| 806 | Dewbre Petroleum Corporation | Corpus Christ, TX 78404 | Oil & Gas Operator | Apr 2026 |
| 807 | Dewbre, Jerry C., Trustee | Corpus Christ, TX 78404 | Oil & Gas Operator | Apr 2026 |
| 808 | Dewco Exploration | Coleman, TX 76834 | Oil & Gas Operator | Nov 2007 |
| 809 | Dewco Oil | | Oil Operator | Jun 1996 |
| 810 | Dewey E. Williams | | Oil Operator | Nov 1978 |
| 811 | Dewey Energy GP LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2022 |
| 812 | Dewey Enterprises Inc | | Oil & Gas Operator | Feb 2026 |
| 813 | Dewey White Etal | | Oil & Gas Operator | Dec 1987 |
| 814 | Dewey Williams | | Oil Operator | Mar 1992 |
| 815 | Dews Production LLC | Magnolia, AR 71753 | Oil & Gas Operator | Jan 2025 |
| 816 | Dexco, Inc. | | Oil & Gas Operator | May 1990 |
| 817 | Dexxon Inc | Kiefer, OK 74041 | Oil & Gas Operator | Feb 2026 |
| 818 | DFG Energy Company LLC | Eastland, TX 76448 | Oil & Gas Operator | Apr 2026 |
| 819 | DFP Oil Company | Tulsa, OK 74114-1345 | Oil & Gas Operator | Dec 2004 |
| 820 | DG&E/Slocum, Limited Partnership | Dallas, TX 75206 | Oil & Gas Operator | Apr 2026 |
| 821 | DGH Oil, LLC | Logan, KS 67646 | Oil Operator | Dec 2025 |
| 822 | DGH Petroleum, Inc. | | Oil & Gas Operator | Aug 2011 |
| 823 | DGP Energy, LLC | Wilmington, DE 19801 | Oil & Gas Operator | Feb 2026 |
| 824 | DH Operating, Inc. | Gordon, TX 76453 | Oil & Gas Operator | Apr 2026 |
| 825 | DH Production | Albany, TX 76430 | Oil Operator | Dec 2005 |
| 826 | DHC, Inc. | Midland, TX 79710 | Oil & Gas Operator | Dec 1997 |
| 827 | DHP Investments, LTD. | Tyler, TX 75703 | Oil Operator | Dec 2025 |
| 828 | DHW Energy LLC | | Oil Operator | Dec 2024 |
| 829 | Di Energy Inc. | Houston, TX 77067 | Oil & Gas Operator | Jan 2004 |
| 830 | Diablo Oil Corp. | | Oil & Gas Operator | Apr 1989 |
| 831 | Diamar Oil Company, Inc. | | Oil Operator | Nov 1983 |
| 832 | Diamex Company | | Oil & Gas Operator | Oct 1982 |
| 833 | Diamond "S" Oil, Inc. | Houston, TX 77065 | Oil & Gas Operator | Apr 1994 |
| 834 | Diamond A Inc. | Tulsa, OK 74137 | Oil & Gas Operator | Jun 2001 |
| 835 | Diamond B Company Inc | Tulsa, OK 74170 | Oil & Gas Operator | Dec 2010 |
| 836 | Diamond B Indust | | Oil Operator | Nov 1996 |
| 837 | Diamond B Industries Inc | Belle Fourche, SD 57717 | Oil & Gas Operator | Apr 2010 |
| 838 | Diamond B Miami Flood, LTD. | Paola, KS 66071 | Oil Operator | Dec 2025 |
| 839 | Diamond Chemical | | Oil & Gas Operator | Jan 1995 |
| 840 | Diamond Cross Oil Co LLC | Ponca City, OK 74601-1104 | Oil & Gas Operator | Feb 2026 |
| 841 | Diamond D Operating | | Oil & Gas Operator | Apr 1995 |
| 842 | Diamond Dixie Ex | | Oil Operator | Jul 1985 |
| 843 | Diamond Drilling Co. | | Oil Operator | Apr 1983 |
| 844 | Diamond E Oil Company LLC | | Oil Operator | Apr 2025 |
| 845 | Diamond Endeavors Inc | | Oil Operator | Dec 2020 |
| 846 | Diamond Energy Operating Company | Tulsa, OK 74137 | Oil & Gas Operator | Mar 2005 |
| 847 | Diamond Energy Partners LLC | Collinsville, OK 74021 | Oil & Gas Operator | Jan 2026 |
| 848 | Diamond Energy Services LLC | Tulsa, OK 74103-3862 | Oil & Gas Operator | Jan 2016 |
| 849 | Diamond Energy Services, LP | Tulsa, OK 74103 | Oil Operator | Apr 2026 |
| 850 | Diamond Energy, Inc. | Sherman, TX 75091 | Oil & Gas Operator | Apr 2026 |
| 851 | Diamond G Production | FT Stockton, TX 79735 | Oil & Gas Operator | Apr 2026 |
| 852 | Diamond Halo Group LLC | Grandview, TX 76050 | Oil Operator | Dec 2025 |
| 853 | Diamond Harry H Inc | Shawnee, OK 74801 | Oil & Gas Operator | Jan 2026 |
| 854 | Diamond M DRLG & Expl Co. | San Antonio, TX 78217 | Oil & Gas Operator | Apr 2026 |
| 855 | Diamond M Oil Co., Inc. | Monahans, TX 79756 | Oil & Gas Operator | Apr 2026 |
| 856 | Diamond M Operating LLC | Kinta, OK 74552 | Gas Operator | Jan 2026 |
| 857 | Diamond Mineral Investments Inc. | Bangs, TX 76823 | Gas Operator | Feb 2008 |
| 858 | Diamond Oil & Gas LLC | Casper, WY 82604 | Oil & Gas Operator | Feb 2026 |
| 859 | Diamond Oil And Gas, Inc. | Kalamazoo, MI 49001 | Oil & Gas Operator | Apr 2026 |
| 860 | Diamond Oil Co | Lancaster, OH 43130 | Oil & Gas Operator | Dec 1992 |
| 861 | Diamond Onshore Production, L. L. C. | | Oil & Gas Operator | Sep 2005 |
| 862 | Diamond Operating Inc | | Oil & Gas Operator | Aug 2021 |
| 863 | Diamond Operating, LLC | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2010 |
| 864 | Diamond Petroleum LLC | | Oil & Gas Operator | Dec 2005 |
| 865 | Diamond Production Company LLC | Irving, TX 75016-7853 | Oil & Gas Operator | Feb 2026 |
| 866 | Diamond S Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Apr 2026 |
| 867 | Diamond S Masada LLC | Magnolia, TX 77354 | Oil & Gas Operator | Apr 2026 |
| 868 | Diamond S Operating Co. | | Oil & Gas Operator | Oct 1992 |
| 869 | Diamond Shamrock Chem Co | Irving, TX 75061 | Oil & Gas Operator | Dec 1990 |
| 870 | Diamond Shamrock Corp | Amarillo, TX 79105 | Oil & Gas Operator | Jan 1987 |
| 871 | Diamond Shamrock Expl | Dallas, TX 75201 | Oil & Gas Operator | May 1987 |
| 872 | Diamond Shamrock Expl. Co. | | Oil & Gas Operator | Jun 1987 |
| 873 | Diamond Star Oil, Inc. | Lacygne, KS 66040 | Oil Operator | Dec 2019 |
| 874 | Diamond T F Enterprises, Inc. | Sonora, TX 76950 | Gas Operator | Apr 2026 |
| 875 | Diamondback E&P LLC | Midland, TX 79701 | Oil & Gas Operator | Apr 2026 |
| 876 | Diamondback Oil Partners LLP | Arvada, CO 80004 | Oil & Gas Operator | Sep 2016 |
| 877 | Diamondback Operating, LP | Tulsa, OK 74132 | Gas Operator | Apr 2026 |
| 878 | Diamondback Resources LLC | Midland, TX 79705 | Oil & Gas Operator | May 2018 |
| 879 | Diamondback-Disposal LLC | Oklahoma City, OK 73134-1016 | Oil Operator | Dec 2008 |
| 880 | Diamondhead Oil Co., LLC | | Oil & Gas Operator | Jan 2026 |
| 881 | Diana Pease & Steve Pease Revocable Trust | Wellsville, NY 14895 | Gas Operator | Dec 2024 |
| 882 | Diane Oil Company | Oklahoma City, OK 73146 | Oil & Gas Operator | Dec 2025 |
| 883 | Diasu Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 884 | Dibiaggio, Deirdre And Katherine Carmichael | Atlantis, FL 33463 | Gas Operator | Dec 2024 |
| 885 | Dick Lindsay Oil Company, Inc. | Graham, TX 76450 | Oil Operator | Apr 2026 |
| 886 | Dickerson Dennis | Velma, OK 73491 | Oil Operator | Jan 2026 |
| 887 | Dickerson Oil | Ada, OK 74820 | Oil Operator | Dec 2025 |
| 888 | Dickey Energy Company | Grafton, WV 26354 | Gas Operator | Dec 2015 |
| 889 | Dickman Farms, LLC | Auburn, NY 13021 | Gas Operator | Dec 2024 |
| 890 | Dickson Petroleum | Midland, TX 79710 | Oil & Gas Operator | Nov 1998 |
| 891 | Dickson Petroleum, Inc. | Midland, TX 79710 | Oil & Gas Operator | May 2000 |
| 892 | Didomenico, Thomas J | Jamestown, NY 14701 | Gas Operator | Dec 2024 |
| 893 | Diehl Glenn D Oi | | Oil Operator | Jul 1993 |
| 894 | Diehl Mark | | Oil Operator | Nov 1998 |
| 895 | Diehl Oil Inc | Hays, KS 67601 | Oil Operator | Dec 2025 |
| 896 | Dieter Prod Comp | | Oil & Gas Operator | Feb 1991 |
| 897 | Dieter Production Company | Durham, KS 67438 | Gas Operator | Mar 2013 |
| 898 | Dietrich Foundation | Pittsburgh, PA 15219 | Gas Operator | Dec 2025 |
| 899 | Dietrich Oil Co., A General Partnership | Humboldt, KS 66748 | Oil Operator | Jul 2000 |
| 900 | Dietrich Philip H | Jefferson, OH 44047 | Oil & Gas Operator | Dec 2024 |