| 1201 | Decker & Associates | | Oil & Gas Operator | Mar 1991 |
| 1202 | Decker Operating Co., L.L.C. | Houston, TX 77008 | Oil & Gas Operator | Feb 2026 |
| 1203 | Deco | Kilgore, TX 75662 | Oil & Gas Operator | Jan 1999 |
| 1204 | Deco Oil Co. | | Oil Operator | Oct 2013 |
| 1205 | Deep South Production | | Oil Operator | Dec 2023 |
| 1206 | Dees Production LLC | | Oil Operator | Dec 2024 |
| 1207 | Dekasco, Inc. | | Oil & Gas Operator | May 1990 |
| 1208 | Delbert A. Dodson | | Oil Operator | Aug 2002 |
| 1209 | Delhi Gas Pipeline Corporation | Palestine, TX 75802 | Oil & Gas Operator | Feb 1998 |
| 1210 | Delmar Operating, Inc. | Houston, TX 77010 | Oil & Gas Operator | Oct 1996 |
| 1211 | Delphi International, Inc. | Tulsa, OK 74104 | Oil Operator | Dec 2025 |
| 1212 | Delta Development Co. Inc. | | Oil & Gas Operator | Dec 1988 |
| 1213 | Delta Energy Resources, Inc. | | Oil & Gas Operator | Jun 1990 |
| 1214 | Delta Expl.& Development Corp. | | Oil & Gas Operator | Jan 2025 |
| 1215 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2026 |
| 1216 | Delta Magic, LTD. | | Oil & Gas Operator | Apr 1988 |
| 1217 | Delta Oil Corp | | Oil & Gas Operator | Dec 2005 |
| 1218 | Delta Operating Company | | Oil Operator | Mar 1987 |
| 1219 | Delta Operating Corporation | | Oil & Gas Operator | Feb 2024 |
| 1220 | Delta Petroleum Corp Of Co | | Oil & Gas Operator | Oct 2010 |
| 1221 | Delta Petroleum Inc | Houston, TX 77269-1007 | Oil & Gas Operator | May 2009 |
| 1222 | Delta Production Services, LLC | | Oil & Gas Operator | Aug 2002 |
| 1223 | Delta Royalties LLC | | Oil & Gas Operator | Dec 2024 |
| 1224 | Deltaus Corporation | | Oil & Gas Operator | Oct 1985 |
| 1225 | Deminex U S Oil Company | | Oil & Gas Operator | Jan 1998 |
| 1226 | Demiran Production, Inc. | | Oil Operator | Mar 2008 |
| 1227 | Dempsey & Rowe | | Oil Operator | Aug 1986 |
| 1228 | Denali Oil & Gas Management LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 1229 | Denbury Management, Inc. | Dallas, TX 75252 | Oil & Gas Operator | Dec 1999 |
| 1230 | Denbury Offshore, Inc. | | Oil & Gas Operator | Nov 2004 |
| 1231 | Denbury Onshore, LLC | Plano, TX 75024 | Oil & Gas Operator | Feb 2026 |
| 1232 | Denbury Resources Inc. | Plano, TX 75024 | Oil & Gas Operator | Dec 2003 |
| 1233 | Denex, Inc. | | Oil & Gas Operator | Jul 1983 |
| 1234 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 1235 | Derrick Petroleum Inc | Bladensburg, OH 43005 | Oil & Gas Operator | Dec 2024 |
| 1236 | Desco Oil Company | Houston, TX 77056 | Oil & Gas Operator | Feb 2017 |
| 1237 | Desco-Medders | | Oil & Gas Operator | Jun 1984 |
| 1238 | Desoto Gas Corporation | | Oil & Gas Operator | Oct 1986 |
| 1239 | Desoto Gas Prod Co Inc-Zadeck | | Gas Operator | Jan 1990 |
| 1240 | Desoto Gas Producing Co. Inc | | Oil & Gas Operator | Jan 1990 |
| 1241 | Desoto Oil & Gas Corporation | | Oil & Gas Operator | Dec 1990 |
| 1242 | Desperation Oil & Gas Co. | | Gas Operator | Jan 1989 |
| 1243 | Despot Expl. Inc-Serio Expl Co | | Oil & Gas Operator | Apr 1990 |
| 1244 | Despot Exploration, Inc. | | Oil & Gas Operator | Apr 1990 |
| 1245 | Despot Production Company | | Oil & Gas Operator | May 1983 |
| 1246 | Despot, Inc. | | Oil & Gas Operator | Mar 1983 |
| 1247 | Destin Operating Company, Inc. | | Oil & Gas Operator | Jan 2023 |
| 1248 | Destin Resources LLC | | Gas Operator | Jul 2018 |
| 1249 | Destin/Lamson | | Gas Operator | Jun 1991 |
| 1250 | Devon Corporation | | Oil Operator | Oct 1981 |
| 1251 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 1252 | Devon Energy Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2009 |
| 1253 | Devon Energy Operating Co., L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2009 |
| 1254 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2026 |
| 1255 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 1256 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 1257 | Dew Oil And Gas Co.,Inc. | | Oil & Gas Operator | Dec 1989 |
| 1258 | Dewco Oil | | Oil Operator | Jun 1996 |
| 1259 | Dewey E. Williams | | Oil Operator | Nov 1978 |
| 1260 | Dewey White Etal | | Oil & Gas Operator | Dec 1987 |
| 1261 | Dewey Williams | | Oil Operator | Mar 1992 |
| 1262 | Dews Production LLC | Magnolia, AR 71753 | Oil & Gas Operator | Jan 2025 |
| 1263 | Dexco, Inc. | | Oil & Gas Operator | May 1990 |
| 1264 | DGH Petroleum, Inc. | | Oil & Gas Operator | Aug 2011 |
| 1265 | Di Energy Inc. | Houston, TX 77067 | Oil & Gas Operator | Jan 2004 |
| 1266 | Diablo Oil Corp. | | Oil & Gas Operator | Apr 1989 |
| 1267 | Diamar Oil Company, Inc. | | Oil Operator | Nov 1983 |
| 1268 | Diamex Company | | Oil & Gas Operator | Oct 1982 |
| 1269 | Diamond D Operating | | Oil & Gas Operator | Apr 1995 |
| 1270 | Diamond Drilling Co. | | Oil Operator | Apr 1983 |
| 1271 | Diamond Oil, LLC | | Oil & Gas Operator | Oct 2012 |
| 1272 | Diamond S Operating Co. | | Oil & Gas Operator | Oct 1992 |
| 1273 | Diamond Shamrock Corp | Amarillo, TX 79105 | Oil & Gas Operator | Jan 1987 |
| 1274 | Diamond Shamrock Expl. Co. | | Oil & Gas Operator | Jun 1987 |
| 1275 | Diasu Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 1276 | Dilligas, Inc. | | Oil Operator | May 1990 |
| 1277 | Dimension Energy Co., L.L.C. | | Oil & Gas Operator | Dec 2024 |
| 1278 | Discovery Energy, LLC | | Oil Operator | Jan 2007 |
| 1279 | Discovery Operating, LLC | | Oil & Gas Operator | Oct 2023 |
| 1280 | Discus Oil Corporation | | Oil & Gas Operator | Dec 2002 |
| 1281 | Ditta Company | | Gas Operator | Apr 2001 |
| 1282 | Ditta Exploration Co., Inc. | | Oil & Gas Operator | Feb 1990 |
| 1283 | Diversified Energy Investments | | Oil & Gas Operator | May 2009 |
| 1284 | Diversified Natural Res., Inc. | | Oil Operator | May 2000 |
| 1285 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Feb 2026 |
| 1286 | Divine'S Service & Repairs Inc | | Oil & Gas Operator | Mar 1997 |
| 1287 | Dixie Operating Company | Spring, TX 77379 | Oil & Gas Operator | Dec 2002 |
| 1288 | Dixie Well Service, Inc. | | Oil & Gas Operator | Jul 1995 |
| 1289 | Dixon Management Corp. | | Oil & Gas Operator | May 1984 |
| 1290 | DKM Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2011 |
| 1291 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Feb 2026 |
| 1292 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Dec 2025 |
| 1293 | Dna Petroleum Inc. | | Oil Operator | Dec 2004 |
| 1294 | Docherty Operating, L.L.C. | | Oil Operator | Dec 2024 |
| 1295 | Dome De Sel LLC | | Oil & Gas Operator | Nov 2024 |
| 1296 | Dome Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2016 |
| 1297 | Domestic Energy Corporation | | Oil Operator | Jan 1988 |
| 1298 | Domestic Oil Producers,Inc. | | Oil Operator | Oct 1998 |
| 1299 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 1300 | Dominion Midstream Services, LP | | Oil Operator | Dec 2006 |