| 3001 | Den Cal, Inc. | Borger, TX 79007 | Oil & Gas Operator | Apr 2025 |
| 3002 | Den-Kay Corp. | Plano, TX 75074 | Oil Operator | Aug 2009 |
| 3003 | Denali Exploration, Inc. | Amarillo, TX 79109 | Oil & Gas Operator | Nov 2018 |
| 3004 | Denali Oil & Gas Management, LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 3005 | Denali Petroleum, LLC | Arlington, TX 76006 | Oil Operator | Mar 2021 |
| 3006 | Denbury Management, Inc. | Dallas, TX 75252 | Oil & Gas Operator | Dec 1999 |
| 3007 | Denbury Onshore, LLC | Plano, TX 75024 | Oil & Gas Operator | Apr 2025 |
| 3008 | Denbury Resources Inc. | Plano, TX 75024 | Oil & Gas Operator | Dec 2003 |
| 3009 | Denhart & Denhart | Brownwood, TX 76804 | Oil & Gas Operator | Dec 2001 |
| 3010 | Denman-Friesen Co. | Lufkin, TX 75901 | Oil & Gas Operator | Nov 2006 |
| 3011 | Dennis & Broun | Bullard, TX 75757 | Oil & Gas Operator | Sep 2003 |
| 3012 | Dennis & Davis Oil Co. | Nocona, TX 76255 | Oil & Gas Operator | Apr 2025 |
| 3013 | Dennis, Don | Grady, OK 73545 | Oil & Gas Operator | Mar 1998 |
| 3014 | Denny'S Inc. | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Dec 2000 |
| 3015 | Denoco Inc. | Plano, TX 75086 | Oil & Gas Operator | Mar 2008 |
| 3016 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 3017 | Denpac Corporation | Colorado SPGS, CO 80922 | Oil & Gas Operator | Apr 2025 |
| 3018 | Denteco Oil Company LLC | Abilene, TX 79604 | Oil & Gas Operator | Apr 2025 |
| 3019 | Denton Exploration, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Apr 2025 |
| 3020 | Denton Oil & Gas | Argyle, TX 76226 | Oil Operator | Dec 2014 |
| 3021 | Denver Energy Exploration,LLC | Canyon Lake, TX 78133 | Oil Operator | Apr 2025 |
| 3022 | Derby Oil Of Texas | Ventura, CA 93003 | Oil & Gas Operator | May 1996 |
| 3023 | Derrick Exploration, Inc. | Amarillo, TX 79105 | Oil & Gas Operator | Jan 2003 |
| 3024 | Derrick Oil & Gas, Inc. | Rosharon, TX 77583 | Oil & Gas Operator | Aug 2003 |
| 3025 | Derwen Operating Company | Houston, TX 77098 | Gas Operator | Dec 2009 |
| 3026 | Desana Development Corporation | Midland, TX 79701 | Oil & Gas Operator | Apr 2025 |
| 3027 | Desco Oil Company | Houston, TX 77056 | Oil & Gas Operator | Feb 2017 |
| 3028 | Desert Production, Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 2025 |
| 3029 | Desert States Energy, Inc. | Hobbs, NM 88240 | Oil & Gas Operator | Aug 1995 |
| 3030 | Devilbiss Contracting, Inc. | Carrizo SPGS, TX 78834 | Oil & Gas Operator | Oct 2005 |
| 3031 | Devine, C. R., Inc. | Houston, TX 77292 | Oil & Gas Operator | Feb 2018 |
| 3032 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 3033 | Devon Energy Operating Co., L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2009 |
| 3034 | Devon Energy Operating Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2013 |
| 3035 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2025 |
| 3036 | Devon Gas Services, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Aug 2023 |
| 3037 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 3038 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 3039 | Devx Operating Company | Frisco, TX 75034 | Oil & Gas Operator | Feb 2004 |
| 3040 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Apr 2025 |
| 3041 | Dewbre, Jerry C., Trustee | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Apr 2025 |
| 3042 | Dewco Exploration | Coleman, TX 76834 | Oil & Gas Operator | Nov 2007 |
| 3043 | Dewey Petroleum | Midland, TX 79707 | Oil & Gas Operator | Dec 2020 |
| 3044 | DFG Energy Company LLC | Eastland, TX 76448 | Oil & Gas Operator | Apr 2025 |
| 3045 | DG&E/Slocum, Limited Partnership | Dallas, TX 75206 | Oil & Gas Operator | Apr 2025 |
| 3046 | DH Operating, Inc. | Gordon, TX 76453 | Oil & Gas Operator | Apr 2025 |
| 3047 | DH Production | Albany, TX 76430 | Oil Operator | Dec 2005 |
| 3048 | DHC, Inc. | Midland, TX 79710 | Oil & Gas Operator | Dec 1997 |
| 3049 | Di Energy Inc. | Houston, TX 77067 | Oil & Gas Operator | Jan 2004 |
| 3050 | Diamond "S" Oil, Inc. | Houston, TX 77065 | Oil & Gas Operator | Apr 1994 |
| 3051 | Diamond A Inc. | Tulsa, OK 74137 | Oil & Gas Operator | Jun 2001 |
| 3052 | Diamond Energy Operating Company | Tulsa, OK 74137 | Oil & Gas Operator | Mar 2005 |
| 3053 | Diamond Energy Services, LP | Tulsa, OK 74103 | Oil Operator | Apr 2025 |
| 3054 | Diamond Energy, Inc. | Sherman, TX 75091 | Oil & Gas Operator | Apr 2025 |
| 3055 | Diamond G Production | FT Stockton, TX 79735 | Oil & Gas Operator | Apr 2025 |
| 3056 | Diamond M DRLG & Expl Co. | San Antonio, TX 78217 | Oil & Gas Operator | Apr 2025 |
| 3057 | Diamond M Oil Co., Inc. | Monahans, TX 79756 | Oil & Gas Operator | Apr 2025 |
| 3058 | Diamond Mineral Investments Inc. | Bangs, TX 76823 | Gas Operator | Feb 2008 |
| 3059 | Diamond Oil & Gas LLC | Casper, WY 82604 | Oil & Gas Operator | Feb 2025 |
| 3060 | Diamond Oil And Gas, Inc. | Kalamazoo, MI 49001 | Oil & Gas Operator | Apr 2025 |
| 3061 | Diamond Operating, LLC | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2010 |
| 3062 | Diamond S Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Apr 2025 |
| 3063 | Diamond S Masada LLC | Magnolia, TX 77354 | Oil & Gas Operator | Apr 2025 |
| 3064 | Diamond T F Enterprises, Inc. | Sonora, TX 76950 | Gas Operator | Apr 2025 |
| 3065 | Diamondback E&P LLC | Midland, TX 79701 | Oil & Gas Operator | Apr 2025 |
| 3066 | Diamondback Oil Partners LLP | Arvada, CO 80004 | Oil & Gas Operator | Dec 2016 |
| 3067 | Diamondback Operating, LP | Tulsa, OK 74132 | Gas Operator | Apr 2025 |
| 3068 | Diamondback Resources LLC | Midland, TX 79705 | Oil & Gas Operator | May 2018 |
| 3069 | Diasu Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 3070 | Dick Lindsay Oil Company, Inc. | Graham, TX 76450 | Oil Operator | Apr 2025 |
| 3071 | Dickson Petroleum, Inc. | Midland, TX 79710 | Oil & Gas Operator | May 2000 |
| 3072 | Digital Operating Company LLC | Boerne, TX 78006 | Oil & Gas Operator | Apr 2025 |
| 3073 | Diler Development Inc. | Garland, TX 75043 | Oil & Gas Operator | Apr 2025 |
| 3074 | Dillard & Dillard Inc. | Holliday, TX 76366 | Oil & Gas Operator | Apr 2025 |
| 3075 | Dillard, A. W., Jr. | Midland, TX 79701 | Oil & Gas Operator | Jan 1995 |
| 3076 | Diller Oil Company | Baird, TX 79504 | Oil Operator | Apr 2025 |
| 3077 | Dillon, H. L., Jr. | Houston, TX 77027 | Oil & Gas Operator | Mar 1996 |
| 3078 | Dime Box Oil Company | Austin, TX 78759 | Oil & Gas Operator | Mar 2008 |
| 3079 | Dimmit County SWD, LLC | Carrizo SPGS, TX 78834 | Oil Operator | Apr 2025 |
| 3080 | Dimock Operating Company | Iowa Park, TX 76367 | Oil & Gas Operator | Apr 2025 |
| 3081 | Dimock Petroleum | Dallas, TX 75205 | Oil Operator | Apr 2014 |
| 3082 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 3083 | Dinero Operating Co | Midland, TX 79702 | Oil & Gas Operator | Apr 2025 |
| 3084 | Dino Operating LLC | Throckmorton, TX 76483 | Oil Operator | Apr 2025 |
| 3085 | Dirks Petroleum Company | Beeville, TX 78104 | Oil & Gas Operator | Apr 2025 |
| 3086 | Dirks, R. W. | Tuleta, TX 78162 | Oil & Gas Operator | May 1999 |
| 3087 | Dirks, R.W. Pet. Eng. Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Jul 1999 |
| 3088 | Dirnett, Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Apr 2025 |
| 3089 | Discorbis Oil Company | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2019 |
| 3090 | Discovery Energy Corp. CC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Apr 2025 |
| 3091 | Discovery Natural Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Apr 2025 |
| 3092 | Discovery Operating Inc | Midland, TX 79705 | Oil & Gas Operator | Apr 2025 |
| 3093 | Discovery Petroleum, L.L.C. | Alice, TX 78333 | Oil & Gas Operator | Apr 2025 |
| 3094 | Dittman, D. W. | Big Lake, TX 76932 | Oil & Gas Operator | Mar 2007 |
| 3095 | Diversified Operating Corp. | Golden, CO 80401 | Oil & Gas Operator | Oct 2012 |
| 3096 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Apr 2025 |
| 3097 | Diversity Petroleum, LP | Rockwall, TX 75087 | Oil & Gas Operator | Aug 2010 |
| 3098 | Dixie Drilling Company, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Nov 2011 |
| 3099 | Dixon Exploration Inc | Abilene, TX 79604 | Oil & Gas Operator | Oct 2019 |
| 3100 | Dixon, N. D. | Midland, TX 79702 | Oil & Gas Operator | Feb 2003 |