| 1201 | Swepi LP | Houston, TX 77079 | Oil & Gas Operator | Jul 2020 |
| 1202 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 1203 | Synergy Offshore LLC | Houston, TX 77024 | Oil & Gas Operator | Feb 2022 |
| 1204 | Synergy Operating LLC | Farmington, NM 87499 | Oil & Gas Operator | Jul 2024 |
| 1205 | T P Production Co | Denver, CO 80202 | Oil & Gas Operator | Nov 1996 |
| 1206 | T-Rex Oil Inc | Broomfield, CO 80021 | Oil Operator | Feb 2011 |
| 1207 | T2 Operating Corporation | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 1208 | Tap Management Inc | Austin, TX 78757 | Oil & Gas Operator | Jan 2023 |
| 1209 | Taqa USA, Inc. | Centennial, CO 80111 | Oil & Gas Operator | Jul 2020 |
| 1210 | Tara Oil Company | | Oil Operator | Dec 1981 |
| 1211 | Target Oil Company | | Oil & Gas Operator | Mar 2007 |
| 1212 | Taylor Oil #13 LLC | Lander, WY 82520 | Oil Operator | Jul 2025 |
| 1213 | Tbi Exploration Inc | Englewood, CO 801556525 | Oil & Gas Operator | Jun 2011 |
| 1214 | Tbi Production Company | Lakewood, CO 80228 | Oil & Gas Operator | Oct 2004 |
| 1215 | TCF Inc | | Gas Operator | Dec 1993 |
| 1216 | Team Operating, L.L.C. | Pinehurst, TX 77362 | Oil & Gas Operator | Oct 2025 |
| 1217 | Teapot Oil & Refining Company | Billings, MT 59101 | Oil & Gas Operator | Mar 2012 |
| 1218 | Temagami Oil & Gas LTD | | Oil & Gas Operator | May 2007 |
| 1219 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Jul 2025 |
| 1220 | Teocali Energy LLC | Denver, CO 80202 | Oil & Gas Operator | Aug 2025 |
| 1221 | Terex Energy Corporation | Casper, WY 82602 | Oil & Gas Operator | Aug 2019 |
| 1222 | Terrapet Corporation | | Oil & Gas Operator | Jun 2011 |
| 1223 | Territory Resources LLC | Stillwater, OK 74074-1869 | Oil & Gas Operator | Aug 2025 |
| 1224 | Terry Production Co | Stroud, OK 74079-0475 | Oil & Gas Operator | Aug 2008 |
| 1225 | Tesoro Petroleum Corporation | | Oil & Gas Operator | May 1982 |
| 1226 | Tex/Con Oil & Gas Company | Houston, TX 77074 | Oil & Gas Operator | Feb 2001 |
| 1227 | Texaco Exploration & Prod | Midland, TX 79702 | Oil & Gas Operator | Aug 2002 |
| 1228 | Texakota | | Oil & Gas Operator | Mar 1995 |
| 1229 | Texas American Oil Corporation | Midland, TX 79701 | Oil & Gas Operator | Jan 2001 |
| 1230 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Oct 2025 |
| 1231 | Texas Gas Exploration Corp. | | Oil & Gas Operator | Nov 1986 |
| 1232 | Texas General Petroleum Corp | | Oil & Gas Operator | Aug 1984 |
| 1233 | Texas Oil & Gas Corporation | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 1234 | Texas Vanguard Oil Company | Austin, TX 78720 | Oil & Gas Operator | Jan 2014 |
| 1235 | TGX Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2004 |
| 1236 | The Brinkerhoff Company | Denver, CO 80202 | Oil & Gas Operator | Dec 2017 |
| 1237 | The Termo Company | Long Beach, CA 90801 | Oil & Gas Operator | Aug 2025 |
| 1238 | Thomas Operating Company Inc | Greeley, CO 80634 | Oil & Gas Operator | Aug 2008 |
| 1239 | Three Forks Resources LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | Oct 2025 |
| 1240 | Three G Inc | Cody, WY 82414 | Oil & Gas Operator | Dec 1999 |
| 1241 | Three Sisters LLC | Cheyenne, WY 82001 | Oil Operator | Aug 2025 |
| 1242 | Thunder Basin Resources LLC | Denver, CO 80203 | Oil & Gas Operator | Jul 2023 |
| 1243 | Ticony Inc | | Oil & Gas Operator | Dec 1989 |
| 1244 | Tidemark Exploration | Tulsa, OK 74170 | Oil & Gas Operator | May 2005 |
| 1245 | Tiger Oil Company | Dallas, TX 75221 | Oil & Gas Operator | May 2007 |
| 1246 | Timberline Energy Inc | Franklin, PA 16323-0269 | Oil & Gas Operator | Dec 2024 |
| 1247 | Timberline Production Company LLC | Casper, WY 82601 | Oil & Gas Operator | Oct 2020 |
| 1248 | Tindall Operating Company | Englewood, CO 80112 | Oil & Gas Operator | Jan 2025 |
| 1249 | Tipperary Oil & Gas Corp | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 1250 | Tipps Kenneth L | | Oil & Gas Operator | Jun 2000 |
| 1251 | Titan Exploration LLC | Denver, CO 80202 | Oil & Gas Operator | Aug 2025 |
| 1252 | Toc Oil Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 2025 |
| 1253 | Toc-Rocky Mountain Inc | | Oil & Gas Operator | Oct 2013 |
| 1254 | Toco Corporation | | Oil & Gas Operator | Oct 1991 |
| 1255 | Tonka Oil & Gas Production Inc | Buffalo, WY 82834 | Oil & Gas Operator | Sep 1999 |
| 1256 | Torch E & P Company | Houston, TX 77010 | Oil & Gas Operator | Jan 2015 |
| 1257 | Torch Oil & Gas Company | Houston, TX 77010 | Oil & Gas Operator | Aug 1997 |
| 1258 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 1259 | Total Petroleum Inc | Houston, TX 77210 | Oil & Gas Operator | Feb 1998 |
| 1260 | Townsend Company | Abilene, TX 79608 | Oil & Gas Operator | Dec 2021 |
| 1261 | TR Operating LLC | Graham, TX 76450 | Oil Operator | Aug 2025 |
| 1262 | Transco Exploration Company | | Oil & Gas Operator | Jul 1989 |
| 1263 | Transcontinental Oil Corp. | | Oil & Gas Operator | Sep 1985 |
| 1264 | Transglobe Oil & Gas Corporation | Littleton, CO 801222710 | Oil & Gas Operator | Dec 1999 |
| 1265 | Transhorizon Energy Inc | Cheyenne, WY 82003 | Oil & Gas Operator | Jul 2023 |
| 1266 | Transworld Systems Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 2025 |
| 1267 | Trend Exploration I LLC | Midland, TX 79701 | Oil & Gas Operator | May 2011 |
| 1268 | Tresor Petroleum | | Oil & Gas Operator | Sep 1987 |
| 1269 | Tressler John R & IVa M | | Oil Operator | Apr 1989 |
| 1270 | Tri-Ex Corporation | | Oil & Gas Operator | Jan 1985 |
| 1271 | Triangle J Oil Company | | Oil & Gas Operator | Mar 2007 |
| 1272 | Tribar Resources LLC | | Oil Operator | Aug 2025 |
| 1273 | Trigg Drilling Company Inc | Oklahoma City, OK 73105 | Oil & Gas Operator | Jan 2013 |
| 1274 | Trigg Oil Mining Corporation | | Oil & Gas Operator | Dec 2007 |
| 1275 | Trinity Energy Resources Inc | Houston, TX 77079 | Oil & Gas Operator | Aug 2005 |
| 1276 | Trinity Resources, Inc. | Houston, TX 77277 | Oil & Gas Operator | May 2020 |
| 1277 | Triple B Energy Inc | Gillette, WY 82716 | Oil Operator | Dec 1999 |
| 1278 | Tripower Resources LLC | Ardmore, OK 73402 | Oil & Gas Operator | Oct 2025 |
| 1279 | Tripp Oil Company Inc | Houston, TX 77023 | Oil & Gas Operator | Jan 1992 |
| 1280 | Tristar Energy Corporation | Casper, WY 82602 | Oil & Gas Operator | Dec 2007 |
| 1281 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 1282 | Trout Kye Jr | | Oil & Gas Operator | Dec 2010 |
| 1283 | True Oil LLC | Casper, WY 82602 | Oil & Gas Operator | Aug 2025 |
| 1284 | Turner Smith & Associates | Englewood, CO 80111 | Oil & Gas Operator | May 1994 |
| 1285 | Twin Arrow Inc | Rangely, CO 81648 | Oil & Gas Operator | Sep 2009 |
| 1286 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 1287 | Tyl Oil | Canon City, CO 81212 | Gas Operator | May 1994 |
| 1288 | Tyler Rockies Exploration LTD | Tyler, TX 75710-0119 | Oil & Gas Operator | Aug 2025 |
| 1289 | Tyrex Oil Company | Casper, WY 82602 | Oil & Gas Operator | May 1997 |
| 1290 | U V Industries | | Oil & Gas Operator | Jan 1993 |
| 1291 | Ultramar Oil & Gas LTD | Houston, TX 77060 | Oil & Gas Operator | Jul 1995 |
| 1292 | Underwood Oil & Gas | Casper, WY 82602 | Oil & Gas Operator | Aug 2025 |
| 1293 | Unicorn Drilling Inc | Cody, WY 82414 | Oil Operator | Dec 1998 |
| 1294 | Unioil | Denver, CO 80203 | Oil & Gas Operator | Jun 2012 |
| 1295 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 1296 | Union Texas Petroleum | Houston, TX 77252 | Oil & Gas Operator | Oct 1991 |
| 1297 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | Apr 2025 |
| 1298 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2025 |
| 1299 | United Energy Corporation | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 1300 | United Natural Gas LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2020 |