| 2901 | DCS Energy | Throckmorton, TX 76483 | Oil Operator | Jul 2025 |
| 2902 | DDC Energy Corporation | Marietta, GA 30068 | Oil & Gas Operator | Mar 1997 |
| 2903 | DDC Production Company | Archer City, TX 76351 | Oil Operator | Jul 2025 |
| 2904 | DDC Track, LLC | Bushland, TX 79012 | Oil Operator | Jul 2025 |
| 2905 | DDD Exploration Inc | Amarillo, TX 79109 | Oil Operator | Jul 2025 |
| 2906 | De Central Operating, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Jul 2025 |
| 2907 | De Compiegne Prop. Co. 20, The | Midland, TX 79702 | Oil Operator | Oct 2019 |
| 2908 | De IV Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Apr 2025 |
| 2909 | De La Torre Oil & Gas, Inc | McAllen, TX 78501 | Oil & Gas Operator | Jul 2025 |
| 2910 | De Larios, R. V., LTD. | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2025 |
| 2911 | De Operating LLC | Austin, TX 78701 | Oil & Gas Operator | Apr 2017 |
| 2912 | De-Vac Inc. | Daisetta, TX 77533 | Oil Operator | Jul 2025 |
| 2913 | De3 Operating LLC | Irving, TX 75038 | Oil & Gas Operator | Jun 2021 |
| 2914 | Deagen, Bill & Sons, LTD. | Stockdale, TX 78160 | Oil Operator | May 2018 |
| 2915 | Dean Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | Nov 2019 |
| 2916 | Deanlake Operator, L.L.C. | Houston, TX 77010 | Oil & Gas Operator | Sep 2011 |
| 2917 | Dearing, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2021 |
| 2918 | Deaton, Gary L. Corporation | Oklahoma City, OK 73105 | Oil & Gas Operator | Mar 2015 |
| 2919 | Deck Oil Company | Tulsa, OK 74101 | Oil & Gas Operator | Jun 2020 |
| 2920 | Decker Operating Co., L.L.C. | Houston, TX 77008 | Oil & Gas Operator | Jul 2025 |
| 2921 | Decleva, Paul | Wichita Falls, TX 76302 | Oil & Gas Operator | Dec 2020 |
| 2922 | Deco | Kilgore, TX 75662 | Oil & Gas Operator | Jan 1999 |
| 2923 | Dedica Energy Corporation | Mattoon, IL 61938 | Oil & Gas Operator | Mar 2008 |
| 2924 | Dee'S Oil | Wellington, TX 79095 | Oil & Gas Operator | Mar 2008 |
| 2925 | Dee-Jay Exploration Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Jul 2025 |
| 2926 | Deen Drilling Company | Archer City, TX 76351 | Oil & Gas Operator | Jul 2025 |
| 2927 | Deep Gully Oil LLC | Houston, TX 77292 | Oil Operator | Jul 2025 |
| 2928 | Deep Reef Industries | Amarillo, TX 79101 | Oil & Gas Operator | Jan 2004 |
| 2929 | Deep Rock Resources, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jul 2025 |
| 2930 | Defranco Oil Account | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2004 |
| 2931 | Deg Energy, Inc. | Magnolia, TX 77354 | Oil & Gas Operator | Feb 2007 |
| 2932 | Deguello Operating LLC | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2025 |
| 2933 | Dekalb Energy Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Oct 1996 |
| 2934 | Del Mar | Holliday, TX 76366 | Oil & Gas Operator | Jul 2025 |
| 2935 | Del Mar Energy, Inc. | Van Alstyne, TX 75495 | Oil & Gas Operator | Jul 2025 |
| 2936 | Del Mar Exploration Company | Houston, TX 77006 | Oil & Gas Operator | Jan 2014 |
| 2937 | Del Petroleum Corporation | Dallas, TX 75219 | Oil & Gas Operator | Jan 2012 |
| 2938 | Del Rio Production Co. | Gainesville, TX 76240 | Oil Operator | Mar 2019 |
| 2939 | Delaware Davis Petroleum Corp. | Houston, TX 77056 | Oil & Gas Operator | Jan 2000 |
| 2940 | Delaware Ecco Petroleum Inc. | Rockwall, TX 75087 | Oil & Gas Operator | Jul 2001 |
| 2941 | Delcar, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 1995 |
| 2942 | Delco Operating Company LP | Houston, TX 77056 | Oil & Gas Operator | May 2020 |
| 2943 | Delek Energy Systems Us Inc | Denver, CO 80202 | Oil & Gas Operator | Oct 2011 |
| 2944 | Delfin Operating, LLC | Dallas, TX 75243 | Oil & Gas Operator | Jul 2025 |
| 2945 | Delgado, Emil A | San Antonio, TX 78223 | Oil & Gas Operator | Sep 2016 |
| 2946 | Delhi Gas Pipeline Corporation | Palestine, TX 75802 | Oil & Gas Operator | Feb 1998 |
| 2947 | Delmar Operating, Inc. | Houston, TX 77010 | Oil & Gas Operator | Oct 1996 |
| 2948 | Delong, Horace | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2025 |
| 2949 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2025 |
| 2950 | Delta C02, LLC | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2021 |
| 2951 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2025 |
| 2952 | Delta Exploration, LLC | Fredericksbrg, TX 78624 | Oil Operator | Jul 2025 |
| 2953 | Delta Oil | Holliday, TX 76366 | Oil & Gas Operator | Sep 2005 |
| 2954 | Delta Oil & Gas Company | Breckenridge, TX 76424 | Oil & Gas Operator | Apr 2003 |
| 2955 | Delta Oil & Gas LTD. | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2025 |
| 2956 | Delta Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2024 |
| 2957 | Deltex Minerals Inc. | Peachtree Cty, GA 30269 | Oil & Gas Operator | Jul 2025 |
| 2958 | Delwintex Oil & Gas Prop., Inc. | Lubbock, TX 79423 | Oil & Gas Operator | Aug 2003 |
| 2959 | Demand Energy, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Jul 1999 |
| 2960 | Demers - Fleming | Wichita Falls, TX 76305 | Oil & Gas Operator | Mar 2008 |
| 2961 | Demers Oil Production | Byers, TX 76357 | Oil & Gas Operator | Apr 2002 |
| 2962 | Demoss, L. V. | Graham, TX 76450 | Oil & Gas Operator | May 2004 |
| 2963 | Den Cal, Inc. | Borger, TX 79007 | Oil & Gas Operator | Jul 2025 |
| 2964 | Den-Kay Corp. | Plano, TX 75074 | Oil Operator | Aug 2009 |
| 2965 | Denali Exploration, Inc. | Amarillo, TX 79109 | Oil & Gas Operator | Nov 2018 |
| 2966 | Denali Oil & Gas Management, LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 2967 | Denali Petroleum, LLC | Arlington, TX 76006 | Oil Operator | Mar 2021 |
| 2968 | Denbury Management, Inc. | Dallas, TX 75252 | Oil & Gas Operator | Dec 1999 |
| 2969 | Denbury Onshore, LLC | Plano, TX 75024 | Oil & Gas Operator | Jul 2025 |
| 2970 | Denbury Resources Inc. | Plano, TX 75024 | Oil & Gas Operator | Dec 2003 |
| 2971 | Denhart & Denhart | Brownwood, TX 76804 | Oil & Gas Operator | Dec 2001 |
| 2972 | Denman-Friesen Co. | Lufkin, TX 75901 | Oil & Gas Operator | Nov 2006 |
| 2973 | Dennis & Broun | Bullard, TX 75757 | Oil & Gas Operator | Sep 2003 |
| 2974 | Dennis & Davis Oil Co. | Nocona, TX 76255 | Oil & Gas Operator | Jul 2025 |
| 2975 | Dennis, Don | Grady, OK 73545 | Oil & Gas Operator | Mar 1998 |
| 2976 | Denny'S Inc. | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Dec 2000 |
| 2977 | Denoco Inc. | Plano, TX 75086 | Oil & Gas Operator | Mar 2008 |
| 2978 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 2979 | Denpac Corporation | Colorado SPGS, CO 80922 | Oil & Gas Operator | Jul 2025 |
| 2980 | Denteco Oil Company LLC | Abilene, TX 79604 | Oil & Gas Operator | Jul 2025 |
| 2981 | Denton Exploration, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Jul 2025 |
| 2982 | Denton Oil & Gas | Argyle, TX 76226 | Oil Operator | Dec 2014 |
| 2983 | Denver Energy Exploration,LLC | Canyon Lake, TX 78133 | Oil Operator | Jul 2025 |
| 2984 | Derby Oil Of Texas | Ventura, CA 93003 | Oil & Gas Operator | May 1996 |
| 2985 | Derrick Exploration, Inc. | Amarillo, TX 79105 | Oil & Gas Operator | Jan 2003 |
| 2986 | Derrick Oil & Gas, Inc. | Rosharon, TX 77583 | Oil & Gas Operator | Aug 2003 |
| 2987 | Derwen Operating Company | Houston, TX 77098 | Gas Operator | Dec 2009 |
| 2988 | Desana Development Corporation | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 2989 | Desco Oil Company | Houston, TX 77056 | Oil & Gas Operator | Feb 2017 |
| 2990 | Desert Production, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 2991 | Desert States Energy, Inc. | Hobbs, NM 88240 | Oil & Gas Operator | Aug 1995 |
| 2992 | Devilbiss Contracting, Inc. | Carrizo SPGS, TX 78834 | Oil & Gas Operator | Oct 2005 |
| 2993 | Devine, C. R., Inc. | Houston, TX 77292 | Oil & Gas Operator | Feb 2018 |
| 2994 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 2995 | Devon Energy Operating Co., L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2009 |
| 2996 | Devon Energy Operating Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2013 |
| 2997 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 2998 | Devon Gas Services, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Nov 2015 |
| 2999 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 3000 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |