| 1501 | Clamp Operating | San Antonio, TX 78264 | Oil & Gas Operator | Apr 2002 |
| 1502 | Clamp Operating Incorporated | San Antonio, TX 78264 | Oil & Gas Operator | Mar 2011 |
| 1503 | Clapp Carl O | Cedar Vale, KS 67024 | Oil Operator | Aug 2013 |
| 1504 | Clapp Oil LLC | | Oil Operator | Jun 2025 |
| 1505 | Clarco Gas Co., Inc. | Westmont, IL 60559 | Oil Operator | Dec 2011 |
| 1506 | Claremont Corporation | Tulsa, OK 74114 | Oil & Gas Operator | Feb 2017 |
| 1507 | Claremont Energy | | Gas Operator | Dec 1993 |
| 1508 | Claremont Exploration Inc | Tulsa, OK 74103-4107 | Oil & Gas Operator | Jun 1997 |
| 1509 | Clarence F. Routon, Jr. | | Oil Operator | Apr 1990 |
| 1510 | Clarence K Tussel Jr LTD | Jefferson, OH 44047 | Oil & Gas Operator | Dec 2024 |
| 1511 | Clarence R. Barnett Inc. | | Oil & Gas Operator | Jul 2025 |
| 1512 | Clarita Operating LLC | Ada, OK 74821 | Oil Operator | Jun 2022 |
| 1513 | Clark And Clark | Princeton, NJ 08540-1930 | Oil & Gas Operator | Jul 2013 |
| 1514 | Clark B & Cahoj | | Oil Operator | Apr 1995 |
| 1515 | Clark Blake | | Gas Operator | Sep 2023 |
| 1516 | Clark Energy, LLC | Chanute, KS 66720 | Oil & Gas Operator | Jun 2022 |
| 1517 | Clark Exploratio | | Oil & Gas Operator | Jun 1991 |
| 1518 | Clark Exploration Company | Highlands Ranch, CO 80126-7645 | Oil & Gas Operator | Nov 2024 |
| 1519 | Clark Krista | Ada, OK 74820-8595 | Oil Operator | Sep 2001 |
| 1520 | Clark Oil & Gas Inc | | Oil & Gas Operator | Dec 1990 |
| 1521 | Clark Oil Co. | Dallas, TX 75360 | Oil & Gas Operator | Dec 2025 |
| 1522 | Clark Oil Producing Company | | Oil & Gas Operator | Oct 1979 |
| 1523 | Clark Oil, LLC | Wellsville, KS 66092 | Oil Operator | Apr 2022 |
| 1524 | Clark Operating | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2003 |
| 1525 | Clark Operating Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 2025 |
| 1526 | Clark Operating Services Inc | Okmulgee, OK 74447 | Oil & Gas Operator | May 2013 |
| 1527 | Clark Well Service | Depew, OK 74028-0296 | Oil & Gas Operator | Aug 2013 |
| 1528 | Clark, B. C. | Cross Plains, TX 76443 | Oil Operator | Dec 2007 |
| 1529 | Clark, Daniel J. | Auburn, NY 13021 | Gas Operator | Dec 2024 |
| 1530 | Clark, Daryl | Phillipsburg, KS 67661 | Oil Operator | Nov 2024 |
| 1531 | Clark, Donald E. | | Gas Operator | Dec 2003 |
| 1532 | Clark, Donald-Roger Young | | Oil & Gas Operator | Jan 1988 |
| 1533 | Clark, G. A., Trustee | San Antonio, TX 78210 | Oil & Gas Operator | Nov 2017 |
| 1534 | Clark, John M. | Midland, TX 79701 | Oil & Gas Operator | Dec 1993 |
| 1535 | Clark, John M., Inc. | Midland, TX 79704 | Oil & Gas Operator | Dec 2025 |
| 1536 | Clark, N.G. Dba Glenn, Inc | | Oil & Gas Operator | Dec 2021 |
| 1537 | Clark, Noel D. Et Al | | Oil & Gas Operator | Mar 1994 |
| 1538 | Clark, Richard E., Inc. | Longview, TX 75604 | Oil & Gas Operator | May 2001 |
| 1539 | Clark, Robert A. | Wichita, KS 67202 | Gas Operator | Jul 1990 |
| 1540 | Clarkco Services, Inc. | | Oil & Gas Operator | Sep 2025 |
| 1541 | Clarke Corporati | Medicine Lodge, KS 67104 | Oil & Gas Operator | Jun 2025 |
| 1542 | Clarkston Oil Co | | Oil Operator | Dec 2024 |
| 1543 | Clarkston Oil Corp | | Oil Operator | Dec 2024 |
| 1544 | Claron Corporation | Houston, TX 77219 | Oil & Gas Operator | Dec 2025 |
| 1545 | Class Oil | Hays, KS 67601 | Oil Operator | Jun 1991 |
| 1546 | Class Petroleum Corporation | Barnsdall, OK 74002 | Oil Operator | Aug 2013 |
| 1547 | Classic Energy Incorporated | Tyler, TX 75701 | Oil & Gas Operator | Jul 2005 |
| 1548 | Classic Hydrocarbons, Inc. | | Gas Operator | Dec 2007 |
| 1549 | Classic Oil & Gas Resources Inc | | Gas Operator | Dec 2008 |
| 1550 | Classic Oil & Gas, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Jan 2004 |
| 1551 | Classic Operating Co. LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 1552 | Classic Petroleum Partners, Inc. | Whitehouse, TX 75791 | Oil & Gas Operator | Dec 2025 |
| 1553 | Classic Well Service, Inc. | Claflin, KS 67525 | Oil Operator | Dec 2019 |
| 1554 | Claude Debeaux, Jr. Et Al | | Oil Operator | Dec 1999 |
| 1555 | Claude S. Hinds | | Oil Operator | Aug 1985 |
| 1556 | Claude-Maggie Co. | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 1557 | Clausen, A. G. | Cross Plains, TX 76443 | Oil & Gas Operator | Dec 2025 |
| 1558 | Clausing, Garry | Coffeyville, KS 67337 | Oil Operator | Apr 2024 |
| 1559 | Claussen Roy A & | | Oil Operator | Jun 1986 |
| 1560 | Clavo Oil, LLC | Graham, TX 76450 | Oil & Gas Operator | Dec 2025 |
| 1561 | Clawson, Merle Eugene | McCune, KS 66753 | Oil Operator | Nov 2016 |
| 1562 | Clay A Muegge | | Oil & Gas Operator | Sep 2025 |
| 1563 | Clay Exploration, Inc. | Spring, TX 77387 | Oil & Gas Operator | Jun 2019 |
| 1564 | Clay Investments LLC | Stillwater, OK 74075-3600 | Oil & Gas Operator | Jan 2021 |
| 1565 | Clay Oil & Gas Co | Zanesville, OH 43701 | Oil Operator | Dec 1991 |
| 1566 | Clay Petroleum | Prosper, TX 75078 | Oil & Gas Operator | Feb 2023 |
| 1567 | Clay, Charles E. | Jacksboro, TX 76458 | Oil & Gas Operator | Sep 2010 |
| 1568 | Clay, Jerry H. | Tyler, TX 75702 | Oil & Gas Operator | Mar 2006 |
| 1569 | Claybanks Oil Co LLC | | Oil Operator | Jun 2019 |
| 1570 | Claybrook Drilling Co Inc | | Oil & Gas Operator | Sep 2014 |
| 1571 | Claybrook Production Co. Inc. | Wewoka, OK 74884-1380 | Oil & Gas Operator | Jun 2014 |
| 1572 | Clayton Corp Petro & Natural Gas Prod | Lakewood, CO 80228-1836 | Oil & Gas Operator | Oct 2020 |
| 1573 | Clayton Corp Petro & NTRL Gas Prodn | Lakewood, CO 80228 | Oil & Gas Operator | Dec 2009 |
| 1574 | Clayton Corporat | | Oil & Gas Operator | Jun 1994 |
| 1575 | Clayton Corporation | Golden, CO 80401 | Oil & Gas Operator | Dec 2019 |
| 1576 | Clayton Investment | Farmington, NM 87401 | Oil & Gas Operator | Jun 1995 |
| 1577 | Clayton Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | May 2004 |
| 1578 | Clayton W. Williams, Jr. | | Oil & Gas Operator | Sep 1986 |
| 1579 | Clayton W. Williams, Jr., Inc. | | Oil & Gas Operator | May 1993 |
| 1580 | Clayton Williams Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Apr 2017 |
| 1581 | CLC Operations Inc | Midland, TX 79701 | Oil & Gas Operator | Mar 1997 |
| 1582 | Clean Energy Exploration & Production LLC | Norristown, PA 19403 | Gas Operator | Sep 2025 |
| 1583 | Clean Energy Systems Placerita Inc. | | Oil & Gas Operator | Sep 2025 |
| 1584 | Clean Gas, Inc | Hindman, KY 41822 | Oil & Gas Operator | Dec 2023 |
| 1585 | Clean Oil LLC | Ada, OK 74820 | Oil & Gas Operator | Aug 2025 |
| 1586 | Cleantex Oilfield Services, LLC | Tyler, TX 75702 | Oil Operator | Dec 2025 |
| 1587 | Clear Brooke Ranches, LLC | Fort Worth, TX 76179 | Oil & Gas Operator | Dec 2025 |
| 1588 | Clear Creek Energy LLC | | Oil & Gas Operator | Dec 2021 |
| 1589 | Clear Creek Exploration LLC | Fredonia, KS 66736 | Gas Operator | Apr 2011 |
| 1590 | Clear Creek Oil Co | Nova, OH 44859 | Oil & Gas Operator | Dec 2018 |
| 1591 | Clear Creek Royalty LLC | Tulsa, OK 74137 | Oil & Gas Operator | Jul 2023 |
| 1592 | Clear Fork Gas Company | Albany, TX 76430 | Oil & Gas Operator | Dec 2025 |
| 1593 | Clear Fork, Incorporated | Abilene, TX 79604 | Oil & Gas Operator | Dec 2025 |
| 1594 | Clear Lake Oil Co. | | Oil Operator | Jan 2025 |
| 1595 | Clear Water Inc. | Midland, TX 79710 | Oil & Gas Operator | Dec 2025 |
| 1596 | Clearfield Energy Resources & Management Inc. | | Oil & Gas Operator | Dec 1998 |
| 1597 | Clearfork Operating LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2011 |
| 1598 | Clearfork Petroleum Inc. (A) | Lubbock, TX 79408 | Oil & Gas Operator | Dec 2025 |
| 1599 | Clearfork Production, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2018 |
| 1600 | Clearly Petroleum, LLC | Houston, TX 77086 | Oil & Gas Operator | Jun 2020 |