| 6001 | Cokinos, Inc. | Beaumont, TX 77701 | Oil & Gas Operator | Aug 2003 |
| 6002 | Col-Kan Developm | | Oil & Gas Operator | Jan 1995 |
| 6003 | Col-Kan Development, Inc. | Russell, KS 67665 | Oil Operator | Jul 2005 |
| 6004 | Cola Resources LLC | Houston, TX 77019-5639 | Gas Operator | Nov 2015 |
| 6005 | Coldharbor Energy, LLC | Northbrook, IL 60062 | Oil & Gas Operator | Jul 2026 |
| 6006 | Coldren Oil & Gas Inc | Bartlesville, OK 74006-4729 | Oil & Gas Operator | Sep 1998 |
| 6007 | Cole, Frank W Engineering | Dallas, TX 75254 | Oil & Gas Operator | Mar 2006 |
| 6008 | Cole, John Otis | Big Spring, TX 79721 | Oil & Gas Operator | Jan 1999 |
| 6009 | Coleman & Johnson Oil Company | Brownwood, TX 76801 | Oil & Gas Operator | Sep 2026 |
| 6010 | Coleman County Project | Coleman, TX 76834 | Oil & Gas Operator | Oct 2012 |
| 6011 | Coleman Oil & Gas Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | Sep 2026 |
| 6012 | Coleman Oil & Gas Inc | Farmington, NM 87499 | Oil & Gas Operator | Jan 2023 |
| 6013 | Coleman Oil Company | Bartlesville, OK 74003 | Oil Operator | Dec 2025 |
| 6014 | Coleman Oil LLC | Marlow, OK 73055 | Oil Operator | Nov 2021 |
| 6015 | Coleman Production | Stroud, OK 74079-9609 | Oil & Gas Operator | May 2013 |
| 6016 | Coleman, C R | | Gas Operator | Dec 2007 |
| 6017 | Colemanite, Inc. | Abilene, TX 79606 | Oil & Gas Operator | Sep 2026 |
| 6018 | Coleville Petroleum Company | McAllen, TX 78503 | Oil & Gas Operator | Mar 1996 |
| 6019 | Coley, H. B. | Corsicana, TX 75110 | Oil & Gas Operator | Oct 2000 |
| 6020 | Coley, Thomas | Graham, TX 76450 | Oil & Gas Operator | Sep 2026 |
| 6021 | Colgate Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Apr 2024 |
| 6022 | Colgrade Investment Corp. | | Oil Operator | Apr 2004 |
| 6023 | Collet Oil Ventures Inc | Denver, CO 80217 | Oil & Gas Operator | Jun 2004 |
| 6024 | Collier Oil Field Services Inc | Iowa Park, TX 76367 | Oil & Gas Operator | Sep 2026 |
| 6025 | Collier Oil Prop | | Oil Operator | Apr 1987 |
| 6026 | Collier Petroleum Corporation | Taloga, OK 73667-9644 | Oil & Gas Operator | Jan 2013 |
| 6027 | Collier, Scott Inc. | Holliday, TX 76366 | Oil Operator | May 2003 |
| 6028 | Collier, W. D. Ranch | Post, TX 79356 | Oil & Gas Operator | Jan 2012 |
| 6029 | Collin C W Jr | | Oil Operator | Oct 2015 |
| 6030 | Collin Oil Operations LLC | | Oil Operator | Jun 2026 |
| 6031 | Collins & Ware, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2003 |
| 6032 | Collins Associates Inc | | Oil & Gas Operator | Mar 1987 |
| 6033 | Collins C R And Collins F Dba Collins Brothers Oil | | Oil & Gas Operator | Jul 2008 |
| 6034 | Collins Dillard Dba Dilco Oil Company | Mangum, OK 73554-4029 | Oil & Gas Operator | Feb 2026 |
| 6035 | Collins John B | | Oil Operator | Sep 1994 |
| 6036 | Collins Oil & Gas Corp | Roswell, NM 88202 | Oil & Gas Operator | Jul 2017 |
| 6037 | Collins Oil Co. | Bartlesville, OK 74006 | Oil & Gas Operator | Dec 2025 |
| 6038 | Collins Oil Comp | | Oil Operator | Apr 1995 |
| 6039 | Collins Oil, LLC | Ellinwood, KS 67526 | Oil Operator | May 2026 |
| 6040 | Collins Petroleum Inc | Bartlesville, OK 74006-7024 | Oil & Gas Operator | Apr 2005 |
| 6041 | Collins Resources, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Mar 2011 |
| 6042 | Collins, Dave | Bolivar, NY 14715 | Oil & Gas Operator | Dec 2025 |
| 6043 | Collins, David A And Cole, Alexander B. | Bolivar, NY 14715 | Oil & Gas Operator | Dec 2025 |
| 6044 | Collins, Paul | | Oil & Gas Operator | Dec 2021 |
| 6045 | Collins, Stephen M | | Oil Operator | Jun 2026 |
| 6046 | Collins-McGregor Operating Company | Marietta, OH 45750 | Oil & Gas Operator | Dec 2025 |
| 6047 | Colo Construction Co., Inc. | Abilene, TX 79602 | Oil Operator | Apr 2004 |
| 6048 | Colo Exploration Company, Inc. | Benbrook, TX 76126 | Oil & Gas Operator | Sep 2026 |
| 6049 | Cologne Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Nov 2014 |
| 6050 | Colonial Corporation | St Simons Island, GA 31522 | Oil & Gas Operator | Dec 2000 |
| 6051 | Colonial Energy Company Inc | Garland, TN 75045 | Oil & Gas Operator | Apr 2015 |
| 6052 | Colonial Resources LLC | Edmond, OK 73003-3207 | Oil & Gas Operator | Aug 2019 |
| 6053 | Colorado Bluebonnet Energy Corp. | Englewood, CO 80112 | Oil & Gas Operator | Feb 2001 |
| 6054 | Colorado Crude E | | Oil Operator | Jan 1986 |
| 6055 | Colorado Drilling Company | Grand Junction, CO 81501 | Oil Operator | Jan 1990 |
| 6056 | Colorado Gas Compression Inc | Longmont, CO 80501-5868 | Oil & Gas Operator | Aug 2013 |
| 6057 | Colorado Interstate Gas Co | Colorado Springs, CO 80944 | Oil & Gas Operator | Jul 2004 |
| 6058 | Colorado Interstate Gas Company LLC | Colorado Springs, CO 80944 | Oil & Gas Operator | May 2026 |
| 6059 | Colorado Oil & G | | Oil & Gas Operator | Oct 1987 |
| 6060 | Colorado Oil & Gas Corporation | | Oil & Gas Operator | Sep 1984 |
| 6061 | Colorado Oil Co., Inc. | | Oil & Gas Operator | Dec 1977 |
| 6062 | Colorado Pica Petro Corp | Cortez, CO 81321 | Oil & Gas Operator | Apr 2007 |
| 6063 | Colorado-Swanson Landing Oil & Gas, LLC | Kilgore, TX 75663 | Oil Operator | Sep 2026 |
| 6064 | Colossus Operating LLC | Kalispell, MT 59901 | Oil Operator | May 2026 |
| 6065 | Colpitt Brothers Oil | Collinsville, OK 74021 | Oil & Gas Operator | Apr 2020 |
| 6066 | Colpitt Brothers Operating Co | Collinsville, OK 74021 | Oil & Gas Operator | Jun 2026 |
| 6067 | Colpitt C H Drilling Co LLC | Collinsville, OK 74021-7107 | Oil Operator | Jun 2026 |
| 6068 | Colpitt Chas H Drilling Co | Collinsville, OK 74021-7105 | Oil & Gas Operator | Mar 2012 |
| 6069 | Colt Energy Inc | Iola, KS 66749 | Oil & Gas Operator | May 2026 |
| 6070 | Colt Energy Inco | | Oil & Gas Operator | Dec 1996 |
| 6071 | Colt Oil & Gas Co. | Abilene, TX 79601 | Oil Operator | Apr 2004 |
| 6072 | Colt Oil Company | Andrews, TX 79714 | Oil & Gas Operator | Feb 1996 |
| 6073 | Colt Oil LLC | Sapulpa, OK 74066-1010 | Oil Operator | Jun 2026 |
| 6074 | Colt Production Corp. Inc. | | Oil & Gas Operator | Jul 1996 |
| 6075 | Colt Resources Corporation | Billings, MT 59103 | Oil & Gas Operator | Feb 2013 |
| 6076 | Colter Operating Co | Horseshoe Bay, TX 78654 | Oil & Gas Operator | Nov 1997 |
| 6077 | Coltharp, Edward H | | Oil & Gas Operator | Dec 1970 |
| 6078 | Colton Limited Liability Co | | Oil & Gas Operator | Sep 2023 |
| 6079 | Coltrane Charles | | Oil Operator | Dec 1980 |
| 6080 | Columbia Energy Properties, Inc. | Baytown, TX 77521 | Oil & Gas Operator | Jul 2004 |
| 6081 | Columbia Gas Dev. Corp. | | Oil & Gas Operator | Apr 1996 |
| 6082 | Columbia Gas Development | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 6083 | Columbia Gas Development Corp. | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 6084 | Columbia Gas Trans Corp | | Gas Operator | Dec 1987 |
| 6085 | Columbia Gas Transmission, LLC | Charleston, WV 25314 | Oil & Gas Operator | Dec 2021 |
| 6086 | Columbia Gulf Transmission Co. | | Oil Operator | Dec 2014 |
| 6087 | Columbia Gulf Transmission Company, LLC | | Oil Operator | Jan 2025 |
| 6088 | Columbia Minerals Corp., Inc. | | Oil & Gas Operator | May 1996 |
| 6089 | Columbia Natural Res Inc | Charleston, WV 25362-0070 | Gas Operator | Dec 2008 |
| 6090 | Columbia Natural Resources, LLC | Charleston, WV 23502 | Oil & Gas Operator | Dec 2021 |
| 6091 | Columbia Oil Company, Inc | | Oil & Gas Operator | Jan 2025 |
| 6092 | Columbia Petrole | | Oil Operator | Sep 1988 |
| 6093 | Columbia Petroleum Corp. | | Oil & Gas Operator | Jun 1982 |
| 6094 | Columbia Petroleum LLC | Oyster Bay, NY 11771 | Oil & Gas Operator | Feb 2025 |
| 6095 | Columbia Petroleum, LTD. | Lewistown, MT 59457 | Oil Operator | Jun 2026 |
| 6096 | Columbia Production Company | Edmond, OK 73083 | Oil & Gas Operator | May 2020 |
| 6097 | Columbian Production Corporation | Topeka, KS 66601 | Oil Operator | Oct 1999 |
| 6098 | Columbian Servic | | Oil & Gas Operator | Nov 1993 |
| 6099 | Columbian Services C | | Oil Operator | Jan 1992 |
| 6100 | Columbian Services Corporation | Topeka, KS 66603 | Gas Operator | Dec 2009 |