| 1801 | Col-Kan Development, Inc. | Russell, KS 67665 | Oil Operator | Jul 2005 |
| 1802 | Cola Resources LLC | Houston, TX 77019-5639 | Gas Operator | Nov 2015 |
| 1803 | Colby Production Resources, LLC | Granbury, TX 76048 | Oil Operator | Dec 2025 |
| 1804 | Coldharbor Energy, LLC | Northbrook, IL 60062 | Oil Operator | Apr 2026 |
| 1805 | Coldren Oil & Gas Inc | Bartlesville, OK 74006-4729 | Oil & Gas Operator | Sep 1998 |
| 1806 | Cole, Frank W Engineering | Dallas, TX 75254 | Oil & Gas Operator | Mar 2006 |
| 1807 | Cole, John Otis | Big Spring, TX 79721 | Oil & Gas Operator | Jan 1999 |
| 1808 | Coleman & Johnson Oil Company | Brownwood, TX 76801 | Oil & Gas Operator | Jul 2026 |
| 1809 | Coleman County Project | Coleman, TX 76834 | Oil & Gas Operator | Oct 2012 |
| 1810 | Coleman Oil & Gas Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | Jul 2026 |
| 1811 | Coleman Oil & Gas Inc | Farmington, NM 87499 | Oil & Gas Operator | Jan 2023 |
| 1812 | Coleman Oil Company | Bartlesville, OK 74003 | Oil Operator | Dec 2025 |
| 1813 | Coleman Oil LLC | Marlow, OK 73055 | Oil Operator | Nov 2021 |
| 1814 | Coleman Production | Stroud, OK 74079-9609 | Oil & Gas Operator | May 2013 |
| 1815 | Coleman, C R | | Gas Operator | Dec 2007 |
| 1816 | Colemanite, Inc. | Abilene, TX 79606 | Oil & Gas Operator | Jul 2026 |
| 1817 | Coleville Petroleum Company | McAllen, TX 78503 | Oil & Gas Operator | Mar 1996 |
| 1818 | Coley, H. B. | Corsicana, TX 75110 | Oil & Gas Operator | Oct 2000 |
| 1819 | Coley, Thomas | Graham, TX 76450 | Oil & Gas Operator | Jul 2026 |
| 1820 | Colgate Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Apr 2024 |
| 1821 | Colgrade Investment Corp. | | Oil Operator | Apr 2004 |
| 1822 | Collet Oil Ventures Inc | Denver, CO 80217 | Oil & Gas Operator | Jun 2004 |
| 1823 | Collier Oil Field Services Inc | Iowa Park, TX 76367 | Oil & Gas Operator | Jul 2026 |
| 1824 | Collier Oil Prop | | Oil Operator | Apr 1987 |
| 1825 | Collier Petroleum Corporation | Taloga, OK 73667-9644 | Oil & Gas Operator | Jan 2013 |
| 1826 | Collier, Scott Inc. | Holliday, TX 76366 | Oil Operator | May 2003 |
| 1827 | Collier, W. D. Ranch | Post, TX 79356 | Oil & Gas Operator | Jan 2012 |
| 1828 | Collin C W Jr | | Oil Operator | Oct 2015 |
| 1829 | Collin Oil Operations LLC | | Oil Operator | Dec 2025 |
| 1830 | Collins & Ware, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2003 |
| 1831 | Collins Associates Inc | | Oil & Gas Operator | Mar 1987 |
| 1832 | Collins C R And Collins F Dba Collins Brothers Oil | | Oil & Gas Operator | Jul 2008 |
| 1833 | Collins Dillard Dba Dilco Oil Company | Mangum, OK 73554-4029 | Oil & Gas Operator | Feb 2026 |
| 1834 | Collins John B | | Oil Operator | Sep 1994 |
| 1835 | Collins Oil & Gas Corp | Roswell, NM 88202 | Oil & Gas Operator | Jul 2017 |
| 1836 | Collins Oil Co. | Bartlesville, OK 74006 | Oil & Gas Operator | Dec 2025 |
| 1837 | Collins Oil Comp | | Oil Operator | Apr 1995 |
| 1838 | Collins Oil, LLC | Ellinwood, KS 67526 | Oil Operator | Mar 2026 |
| 1839 | Collins Petroleum Inc | Bartlesville, OK 74006-7024 | Oil & Gas Operator | Apr 2005 |
| 1840 | Collins Resources, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Mar 2011 |
| 1841 | Collins, Dave | Bolivar, NY 14715 | Oil & Gas Operator | Dec 2025 |
| 1842 | Collins, David A And Cole, Alexander B. | Bolivar, NY 14715 | Oil & Gas Operator | Dec 2025 |
| 1843 | Collins, Paul | Big Springs, WV 26137-0000 | Oil & Gas Operator | Dec 2021 |
| 1844 | Collins, Stephen M | | Oil Operator | Apr 2026 |
| 1845 | Collins-McGregor Operating Company | Marietta, OH 45750 | Oil & Gas Operator | Dec 2025 |
| 1846 | Colo Construction Co., Inc. | Abilene, TX 79602 | Oil Operator | Apr 2004 |
| 1847 | Colo Exploration Company, Inc. | Benbrook, TX 76126 | Oil & Gas Operator | Jul 2026 |
| 1848 | Cologne Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Nov 2014 |
| 1849 | Colonial Corporation | St Simons Island, GA 31522 | Oil & Gas Operator | Dec 2000 |
| 1850 | Colonial Energy Company Inc | Garland, TN 75045 | Oil & Gas Operator | Apr 2015 |
| 1851 | Colonial Hardwoods Inc | Luthersburg, PA 15848-3506 | Gas Operator | Dec 2019 |
| 1852 | Colonial Resources LLC | Edmond, OK 73003-3207 | Oil & Gas Operator | Aug 2019 |
| 1853 | Colorado Bluebonnet Energy Corp. | Englewood, CO 80112 | Oil & Gas Operator | Feb 2001 |
| 1854 | Colorado Crude E | | Oil Operator | Jan 1986 |
| 1855 | Colorado Drilling Company | Grand Junction, CO 81501 | Oil Operator | Jan 1990 |
| 1856 | Colorado Gas Compression Inc | Longmont, CO 80501-5868 | Oil & Gas Operator | Aug 2013 |
| 1857 | Colorado Interstate Gas Co | Colorado Springs, CO 80944 | Oil & Gas Operator | Jul 2004 |
| 1858 | Colorado Interstate Gas Company LLC | Colorado Springs, CO 80944 | Oil & Gas Operator | May 2026 |
| 1859 | Colorado Oil & G | | Oil & Gas Operator | Oct 1987 |
| 1860 | Colorado Oil & Gas Corporation | | Oil & Gas Operator | Sep 1984 |
| 1861 | Colorado Oil Co., Inc. | | Oil & Gas Operator | Dec 1977 |
| 1862 | Colorado Pica Petro Corp | Cortez, CO 81321 | Oil & Gas Operator | Apr 2007 |
| 1863 | Colorado-Swanson Landing Oil & Gas, LLC | Kilgore, TX 75663 | Oil Operator | Jul 2026 |
| 1864 | Colossus Operating LLC | Kalispell, MT 59901 | Oil Operator | May 2026 |
| 1865 | Colotex Operating, LLC | Aurora, CO 80015 | Oil & Gas Operator | Jul 2026 |
| 1866 | Colpitt Brothers Oil | Collinsville, OK 74021 | Oil & Gas Operator | Apr 2020 |
| 1867 | Colpitt Brothers Operating Co | Collinsville, OK 74021 | Oil & Gas Operator | May 2026 |
| 1868 | Colpitt C H Drilling Co LLC | Collinsville, OK 74021-7107 | Oil Operator | Apr 2026 |
| 1869 | Colpitt Chas H Drilling Co | Collinsville, OK 74021-7105 | Oil & Gas Operator | Mar 2012 |
| 1870 | Colt Energy Inc | Iola, KS 66749 | Oil & Gas Operator | Mar 2026 |
| 1871 | Colt Energy Inco | | Oil & Gas Operator | Dec 1996 |
| 1872 | Colt Oil & Gas Co. | Abilene, TX 79601 | Oil Operator | Apr 2004 |
| 1873 | Colt Oil Company | Andrews, TX 79714 | Oil & Gas Operator | Feb 1996 |
| 1874 | Colt Oil LLC | Sapulpa, OK 74066-1010 | Oil Operator | Mar 2026 |
| 1875 | Colt Production Corp. Inc. | | Oil & Gas Operator | Jul 1996 |
| 1876 | Colt Resources Corporation | Billings, MT 59103 | Oil & Gas Operator | Feb 2013 |
| 1877 | Colter Operating Co | Horseshoe Bay, TX 78654 | Oil & Gas Operator | Nov 1997 |
| 1878 | Coltharp, Edward H | | Oil & Gas Operator | Dec 1970 |
| 1879 | Colton Limited Liability Co | | Oil & Gas Operator | Sep 2023 |
| 1880 | Coltrane Charles | | Oil Operator | Dec 1980 |
| 1881 | Columbia Energy Properties, Inc. | Baytown, TX 77521 | Oil & Gas Operator | Jul 2004 |
| 1882 | Columbia Gas Dev. Corp. | | Oil & Gas Operator | Apr 1996 |
| 1883 | Columbia Gas Development | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 1884 | Columbia Gas Development Corp. | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 1885 | Columbia Gas Trans LLC | Charleston, WV 25325-1273 | Gas Operator | Dec 1987 |
| 1886 | Columbia Gas Transmission, LLC | Charleston, WV 25314 | Oil & Gas Operator | Dec 2021 |
| 1887 | Columbia Gulf Transmission Co. | | Oil Operator | Dec 2014 |
| 1888 | Columbia Gulf Transmission Company, LLC | | Oil Operator | Jan 2025 |
| 1889 | Columbia Minerals Corp., Inc. | | Oil & Gas Operator | May 1996 |
| 1890 | Columbia Natural Res Inc | Charleston, WV 25362-0070 | Gas Operator | Dec 2008 |
| 1891 | Columbia Natural Resources, LLC | Charleston, WV 23502 | Oil & Gas Operator | Dec 2021 |
| 1892 | Columbia Oil Company, Inc | Guy, AR 72061 | Oil & Gas Operator | Jan 2025 |
| 1893 | Columbia Petrole | | Oil Operator | Sep 1988 |
| 1894 | Columbia Petroleum Corp. | | Oil & Gas Operator | Jun 1982 |
| 1895 | Columbia Petroleum LLC | Oyster Bay, NY 11771 | Oil & Gas Operator | Feb 2025 |
| 1896 | Columbia Petroleum, LTD. | Lewistown, MT 59457 | Oil Operator | Apr 2026 |
| 1897 | Columbia Production Company | Edmond, OK 73083 | Oil & Gas Operator | May 2020 |
| 1898 | Columbian Production Corporation | Topeka, KS 66601 | Oil Operator | Oct 1999 |
| 1899 | Columbian Servic | | Oil & Gas Operator | Nov 1993 |
| 1900 | Columbian Services C | | Oil Operator | Jan 1992 |