| 1401 | Ducky Oil Corporation | Fort Worth, TX 76120 | Oil & Gas Operator | Sep 2025 |
| 1402 | Duco Energy LLC | Tulsa, OK 74145-4514 | Oil & Gas Operator | Mar 2015 |
| 1403 | Ducote Oil Co. | | Oil & Gas Operator | Sep 1997 |
| 1404 | Duderstadt, A. R. | Boling, TX 77420 | Oil & Gas Operator | Sep 2025 |
| 1405 | Dudley Oil Co. | Crane, TX 79731 | Oil & Gas Operator | Jan 2006 |
| 1406 | Dudrey Carl | | Oil & Gas Operator | Feb 1993 |
| 1407 | Duer Wagner & Company | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1998 |
| 1408 | Duerfeldt | | Oil Operator | Dec 2024 |
| 1409 | Duff Oil Co | | Oil & Gas Operator | Aug 2000 |
| 1410 | Duffer William R | Edmond, OK 73034-6761 | Oil & Gas Operator | Aug 2018 |
| 1411 | Duffield, Scott | | Gas Operator | Dec 2021 |
| 1412 | Dugan Evan | Martinsburg, OH 43037 | Oil & Gas Operator | Dec 2024 |
| 1413 | Dugan Guy E | Walhonding, OH 43843 | Oil & Gas Operator | Dec 2015 |
| 1414 | Dugan Harry Oil Co | Newark, OH 43055 | Oil & Gas Operator | Dec 1993 |
| 1415 | Dugan Oil And Gas LLC | Walhonding, OH 43843-9612 | Oil & Gas Operator | Dec 2024 |
| 1416 | Dugan Production Corp | Farmington, NM 87499 | Oil & Gas Operator | Jun 2025 |
| 1417 | Duggan Stephen F | Boston, MA 2131 | Oil & Gas Operator | Jun 2010 |
| 1418 | Dugger, Glenn | Alice, TX 78332 | Oil & Gas Operator | Nov 2013 |
| 1419 | Duggins Equipment Inc | Woodward, OK 73802-1213 | Gas Operator | Jun 2025 |
| 1420 | Duhring Resource Co | Sheffield, PA 16347-2642 | Oil & Gas Operator | Dec 2012 |
| 1421 | Duink, Darryl | Hamburg, NY 14075 | Gas Operator | Dec 2024 |
| 1422 | Duke Drilling Co | Wichita, KS 67202 | Oil & Gas Operator | Feb 2006 |
| 1423 | Duke Energy Field Services Inc | | Oil Operator | Mar 2000 |
| 1424 | Duke Energy Field Services LLC | | Oil Operator | Dec 2006 |
| 1425 | Duke Gas Company LLC | | Gas Operator | Jul 2025 |
| 1426 | Duke Oil & Gas Company, LLC | Wellsville, KS 66092 | Oil Operator | May 2025 |
| 1427 | Duke Oil & Gas Inc | Colorado City, TX 79512 | Oil & Gas Operator | May 2003 |
| 1428 | Duke Oil LLC | Garnett, KS 66032 | Oil Operator | May 2025 |
| 1429 | Duke Operating Company | Graham, TX 76450 | Oil Operator | Sep 2025 |
| 1430 | Duke, M. L. | Snyder, TX 79549 | Oil & Gas Operator | Mar 2008 |
| 1431 | Duke, M.A. "Andy", Jr. | Montague, TX 76251 | Oil & Gas Operator | Jun 2023 |
| 1432 | Dukes T F | | Oil & Gas Operator | Apr 2007 |
| 1433 | Dula Production, LLC | Stockdale, TX 78160 | Oil Operator | Sep 2025 |
| 1434 | Dunamis Energy Operating LLC | | Oil & Gas Operator | Jun 2025 |
| 1435 | Dunbar & Son Oil | | Oil & Gas Operator | Oct 1988 |
| 1436 | Dunbar, Ron, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2012 |
| 1437 | Duncan Drilling Co. | Big Spring, TX 79721 | Oil & Gas Operator | Sep 2025 |
| 1438 | Duncan Energy Company | Denver, CO 80202 | Oil & Gas Operator | Mar 2008 |
| 1439 | Duncan Energy Companyuncan Energy Company | Denver, CO 80210 | Oil & Gas Operator | Jun 1995 |
| 1440 | Duncan Energy LLC | Dallas, TX 75231 | Oil & Gas Operator | Sep 2025 |
| 1441 | Duncan Jr J Walter | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2016 |
| 1442 | Duncan Land & Exploration, Inc. | Graham, TX 76450 | Oil & Gas Operator | Sep 2025 |
| 1443 | Duncan Oil & Gas Inc | Norman, OK 73072 | Oil & Gas Operator | Sep 2020 |
| 1444 | Duncan Oil Company | Holliday, TX 76366 | Oil Operator | Mar 2008 |
| 1445 | Duncan Oil Inc | Denver, CO 80210 | Oil & Gas Operator | Jun 2016 |
| 1446 | Duncan Oil Properties, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2025 |
| 1447 | Duncan Ronald R | Okemah, OK 74859-9603 | Oil & Gas Operator | Aug 2023 |
| 1448 | Duncan, Gene L Dba Duncan Oil Co | Salem, IL 62881 | Oil Operator | Dec 2018 |
| 1449 | Duncan, Raymond T | Denver, CO 80210 | Oil & Gas Operator | Feb 1996 |
| 1450 | Duncan-Taylor & Schumacher | | Oil & Gas Operator | Nov 1987 |
| 1451 | Dundee Oil & Supply Inc | Tulsa, OK 74101 | Oil & Gas Operator | Apr 2001 |
| 1452 | Dundee Petroleum, Inc. | Buffalo Gap, TX 79508 | Oil & Gas Operator | Aug 2003 |
| 1453 | Dune Oil And Gas, Inc. | Odessa, TX 79768 | Oil & Gas Operator | Aug 2006 |
| 1454 | Dune Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Jun 2016 |
| 1455 | Dune Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 1997 |
| 1456 | Dune Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Jan 1993 |
| 1457 | Dunham'S Oil, LLC | Eureka, KS 67045 | Oil Operator | May 2025 |
| 1458 | Dunhill Expl. & Prod., LLC | | Oil & Gas Operator | Nov 2004 |
| 1459 | Dunhill Resources, Inc. | | Oil & Gas Operator | Nov 2005 |
| 1460 | Dunigan Operating Company, Inc. | Austin, TX 78755 | Oil & Gas Operator | Sep 2025 |
| 1461 | Dunigan Petroleum, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 1462 | Dunkin Oil And Gas LLC | Wynewood, OK 73098-9196 | Oil Operator | May 2025 |
| 1463 | Dunkirk City School District | Dunkirk, NY 14048 | Gas Operator | Dec 2024 |
| 1464 | Dunlap Drilling And Producing, Inc | Glenpool, OK 74033-4206 | Oil & Gas Operator | Jul 2025 |
| 1465 | Dunlap Exploration, Inc. | Fort Worth, TX 76101 | Oil & Gas Operator | Nov 2016 |
| 1466 | Dunlap Oil Company | Bristow, OK 74010 | Oil & Gas Operator | Jun 2025 |
| 1467 | Dunlap Well Service Inc | Haskell, OK 74436 | Oil & Gas Operator | Sep 1993 |
| 1468 | Dunlap, Rodge | Olney, TX 76374 | Oil & Gas Operator | Aug 2002 |
| 1469 | Dunn Energy LLC | Skiatook, OK 74070-4046 | Oil Operator | Sep 2022 |
| 1470 | Dunn Exploration Company, LLC | | Oil & Gas Operator | Jan 2025 |
| 1471 | Dunn Joseph L | Washington, PA 15301-6404 | Oil & Gas Operator | Dec 2024 |
| 1472 | Dunn Resources, LLC | Shreveport, LA 71115 | Oil & Gas Operator | Mar 2023 |
| 1473 | Dunn'S Oil And Gas Lease Management LLC | Ardmore, OK 73401 | Oil & Gas Operator | Jun 2025 |
| 1474 | Dunne Equities I | | Oil & Gas Operator | Dec 1995 |
| 1475 | Dunne Equities Operating, Inc. | Houston, TX 77057 | Oil & Gas Operator | Aug 2022 |
| 1476 | Dunne Equities, Inc. | Wichita, KS 67226 | Oil & Gas Operator | Apr 2014 |
| 1477 | Dunne Investments Operating, Inc. | Wichita, KS 67226 | Oil Operator | Mar 2002 |
| 1478 | Dunne Oil Co. | Wichita, KS 67202 | Oil Operator | Apr 1999 |
| 1479 | Dunne-Gardner Pe | | Oil & Gas Operator | Nov 1992 |
| 1480 | Dunne-Gardner Petroleum, Inc. | Wichita, KS 67202 | Gas Operator | Jun 2022 |
| 1481 | Dunnewold Farms LLC | Clymer, NY 14724 | Gas Operator | Dec 2024 |
| 1482 | Dunsmoor, David E. | Grand Junction, CO 81504 | Oil Operator | Jul 1998 |
| 1483 | Dupke Roger Oil Co Inc | Reno, OH 45773 | Oil & Gas Operator | Dec 2004 |
| 1484 | Duplantis Energy, LLC | Pleasanton, TX 78064 | Oil Operator | Sep 2025 |
| 1485 | Dupont Oil Company | | Oil Operator | Feb 1998 |
| 1486 | Dupree And Dupree | | Oil Operator | Dec 1998 |
| 1487 | Durango Energy Inc | Chickasha, OK 73023 | Oil Operator | Dec 1999 |
| 1488 | Durango Exploration LLC | Oklahoma City, OK 73120-5309 | Oil & Gas Operator | Jul 2025 |
| 1489 | Durango Operating Co., Inc. | Abilene, TX 79604 | Oil & Gas Operator | Feb 2002 |
| 1490 | Durango Operating, LLC | Madison, MS 39110 | Oil & Gas Operator | Jun 2025 |
| 1491 | Durango Resources Corp. | Houston, TX 77043 | Oil & Gas Operator | Sep 2025 |
| 1492 | Durbin, Ronald R. | Moline, KS 67353 | Oil Operator | Dec 1988 |
| 1493 | Durham, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jul 2016 |
| 1494 | Duroc Exploration LLC | Bixby, OK 74008 | Oil Operator | Jun 2025 |
| 1495 | Durossette Bill D | Haskell, OK 74436-1350 | Oil & Gas Operator | Jul 2004 |
| 1496 | Durossette Floyd R | Warner, OK 74469-0548 | Oil & Gas Operator | Apr 2011 |
| 1497 | Durossette Jr Jess | Haskell, OK 74436 | Oil Operator | Mar 2007 |
| 1498 | Durst Oil & Gas, Inc. | Point Pleasant, WV 25550 | Oil & Gas Operator | Dec 2021 |
| 1499 | Durst Oil Company | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Sep 2000 |
| 1500 | Dust Bowl Oil Company, Inc. | Spencerport, NY 14559 | Oil Operator | Dec 2024 |