| 1 | 44 Mag Production Inc | | Gas Operator | Mar 2012 |
| 2 | Aberdeen Petroleum (USA) Inc. | Abilene, TX 79608 | Oil & Gas Operator | Sep 1994 |
| 3 | Abraxas Petroleum Corporation | San Antonio, TX 78259 | Oil & Gas Operator | Dec 2024 |
| 4 | Adams H D LLC | Moorcroft, WY 82721 | Oil & Gas Operator | Nov 2024 |
| 5 | Adobe Resources Corporation | Midland, TX 79701 | Oil & Gas Operator | Aug 2002 |
| 6 | Aexco Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Nov 2024 |
| 7 | Allen And Schramm Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 1996 |
| 8 | Alpha Coal West Inc | Gillette, WY 82716 | Oil & Gas Operator | Jun 2020 |
| 9 | Altex Oil Company | Breckenridge, CO 80424 | Oil & Gas Operator | Dec 2005 |
| 10 | Am-West Petroleum Inc | Upton, WY 82730 | Oil & Gas Operator | Sep 2015 |
| 11 | Amarex Inc | | Oil & Gas Operator | Dec 1996 |
| 12 | Amax Oil & Gas Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 13 | Amberex Corporation | Denver, CO 80237 | Oil & Gas Operator | Sep 1984 |
| 14 | Aminoil USA Inc | | Oil & Gas Operator | Jan 1985 |
| 15 | Ampolex Wy Inc | Gillette, WY 82716 | Oil & Gas Operator | Mar 1997 |
| 16 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Dec 2024 |
| 17 | Anadarko Minerals Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Nov 2024 |
| 18 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Nov 2024 |
| 19 | Anchor Bay Corporation | Denver, CO 80202 | Oil & Gas Operator | Jun 2007 |
| 20 | Anderson Management Company | Gillette, WY 82716 | Oil & Gas Operator | May 2016 |
| 21 | Anderson Oil Company | Burkburnett, TX 76354 | Oil & Gas Operator | Dec 2015 |
| 22 | Andrikopoulos A G | Cheyenne, WY 82009 | Oil & Gas Operator | Dec 1994 |
| 23 | Anr Production Company | Houston, TX 77046 | Oil & Gas Operator | Aug 2017 |
| 24 | Anschutz Corporation, The | Denver, CO 80202 | Oil & Gas Operator | Sep 2016 |
| 25 | Anschutz Exploration Corporation | Denver, CO 80202 | Oil & Gas Operator | Dec 2024 |
| 26 | Anschutz Oil Company LLC | Denver, CO 80202 | Oil & Gas Operator | Sep 2020 |
| 27 | Ant Hills Production | Lusk, WY 82225 | Oil & Gas Operator | Nov 2024 |
| 28 | Antelope Energy Company LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2024 |
| 29 | Antero Energy LLC | Denver, CO 80202 | Gas Operator | Nov 2003 |
| 30 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Dec 2024 |
| 31 | Apc Operating Partnership | Tulsa, OK 74136 | Oil & Gas Operator | Oct 1996 |
| 32 | Apx Western Corporation | Denver, CO 80217 | Oil & Gas Operator | Sep 1991 |
| 33 | Aquarius Oil And Gas | Casper, WY 82601 | Oil & Gas Operator | Sep 2017 |
| 34 | Argent Energy (Us) Holdings Inc | Sugar Land, TX 77479 | Oil & Gas Operator | Sep 2021 |
| 35 | Argentia Operating Company | | Oil Operator | Oct 1991 |
| 36 | Atlantic Richfield Company | Plano, TX 75074 | Oil & Gas Operator | Dec 2016 |
| 37 | Atomic Oil & Gas LLC | Lakewood, CO 80228 | Oil & Gas Operator | Dec 2012 |
| 38 | Atr Energy Corp | Dallas, TX 75313 | Oil Operator | Oct 2024 |
| 39 | Avalon Energy Corporation | | Oil & Gas Operator | Jul 1990 |
| 40 | Axem Resources Inc | Denver, CO 80202-4617 | Oil & Gas Operator | Jul 2013 |
| 41 | Azalea Oil Company LLC | Castle Rock, CO 80108 | Oil Operator | Nov 2024 |
| 42 | Aztec Gas And Oil Corporation | Elephant Butte, NM 87935-0370 | Oil & Gas Operator | Mar 2005 |
| 43 | Ballard Petroleum Holdings LLC | Billings, MT 59104 | Oil & Gas Operator | Nov 2024 |
| 44 | Bandera Energy Company | | Oil & Gas Operator | Mar 1986 |
| 45 | Banding M R Inc | Gillette, WY 82717 | Oil & Gas Operator | Nov 2024 |
| 46 | Banks And Conrad | | Oil Operator | Sep 1987 |
| 47 | Banks Operating Company | | Oil & Gas Operator | Jul 1989 |
| 48 | Banta And Haigh | Aurora, CO 80014 | Oil & Gas Operator | Feb 1998 |
| 49 | Barbe D F | Recluse, WY 82725 | Oil & Gas Operator | Dec 2000 |
| 50 | Barn Owls LLC | | Oil & Gas Operator | Oct 2024 |
| 51 | Bass Enterprises Production Co | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2006 |
| 52 | Baytex Energy USA LLC | Denver, CO 80202 | Oil & Gas Operator | Nov 2014 |
| 53 | Bear Oil And Gas Inc | Las Vegas, NV 89107 | Oil & Gas Operator | Jul 2016 |
| 54 | Bearcat Energy LLC (Colorado) | Denver, CO 80202 | Oil & Gas Operator | May 2022 |
| 55 | Beard Oil Company | Oklahoma City, OK 73102 | Oil & Gas Operator | Aug 2013 |
| 56 | Beartooth Oil & Gas Company | Billings, MT 59103 | Oil & Gas Operator | Nov 2024 |
| 57 | Bellevue Resources Inc | Lakewood, CO 80235 | Oil & Gas Operator | Feb 2009 |
| 58 | Benchmark Energy LLC | Pratt, KS 67124 | Oil & Gas Operator | Sep 2023 |
| 59 | Benson-Montin-Greer DRLG Corp | Farmington, NM 87402 | Oil & Gas Operator | Dec 2024 |
| 60 | Beren Corporation | Wichita, KS 67206 | Oil & Gas Operator | Dec 2024 |
| 61 | Berenergy Corporation | Denver, CO 80217 | Oil & Gas Operator | Nov 2024 |
| 62 | Betop Inc | Ojai, CA 83203 | Oil & Gas Operator | Dec 1996 |
| 63 | BHP Petroleum Company Inc | Houston, TX 77057 | Oil & Gas Operator | Jun 2016 |
| 64 | Big Basin Petroleum LLC | Gillette, WY 82717 | Oil & Gas Operator | Oct 2008 |
| 65 | Big Chief Exploration | Palisades, CO 81526 | Oil & Gas Operator | Oct 1993 |
| 66 | Big Piney Oil & Gas Company | Dallas, TX 75206 | Oil & Gas Operator | Sep 1992 |
| 67 | Bill Barrett Corporation | Denver, CO 80202 | Oil & Gas Operator | Dec 2017 |
| 68 | Black Bear Oil Corporation | Las Vegas, NV 89128 | Oil & Gas Operator | Oct 2024 |
| 69 | Black Diamond Energy Inc | Pittsburgh, PA 15237 | Gas Operator | May 2016 |
| 70 | Black Hawk Resources Corporation | Denver, CO 80202 | Oil Operator | Mar 1986 |
| 71 | Black Hills Exploration & Production Inc | Newcastle, WY 82701 | Oil & Gas Operator | May 2018 |
| 72 | Black Jack Oil Co Inc | Holliday, TX 76366 | Oil & Gas Operator | Oct 2024 |
| 73 | Blackjack Oil, Inc. | Las Vegas, NV 89128 | Oil & Gas Operator | Nov 2019 |
| 74 | Blackstone Operating Inc | Red Lodge, MT 59068 | Gas Operator | Nov 2009 |
| 75 | Blake Production LLC | Gillette, WY 82717 | Oil & Gas Operator | Jul 2024 |
| 76 | Bluebonnet Energy Corporation | Englewood, CO 80112 | Oil & Gas Operator | Sep 2015 |
| 77 | Bowden Energy Company Inc | Gillette, WY 82716 | Oil & Gas Operator | Oct 2024 |
| 78 | Bowers Oil & Gas, Inc. | Grand Junction, CO 81505-1097 | Oil & Gas Operator | Nov 2022 |
| 79 | BP America Production Company | Denver, CO 80202 | Oil & Gas Operator | Oct 2024 |
| 80 | BP Exploration Inc | | Oil & Gas Operator | May 1993 |
| 81 | Braden Oil | | Oil & Gas Operator | Mar 2007 |
| 82 | Bradley Jr Jack C | Casper, WY 82601 | Oil & Gas Operator | Apr 2009 |
| 83 | Bradley SR Jack C | Newcastle, WY 82701 | Oil Operator | Jun 2010 |
| 84 | Brannon Oil & Gas Inc | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2013 |
| 85 | Breck Operating Corp. | Breckenridge, TX 76424 | Oil & Gas Operator | Oct 2024 |
| 86 | Brent Exploration | | Oil & Gas Operator | Dec 1993 |
| 87 | Bridger Petroleum Corp | | Oil & Gas Operator | Oct 1999 |
| 88 | Briscoe Petroleum, LLC | Sheridan, WY 82801 | Oil & Gas Operator | Nov 2024 |
| 89 | Brower Oil & Gas Inc | Jenks, OK 74037 | Oil & Gas Operator | Nov 2022 |
| 90 | Brown J K Inc | Denver, CO 80202 | Oil & Gas Operator | Jan 2003 |
| 91 | Brown Operating Inc | Casper, WY 82602 | Oil & Gas Operator | May 2019 |
| 92 | Brown Shirley | Buffalo, WY 82834 | Oil & Gas Operator | Oct 2010 |
| 93 | Brown Tom Inc | Dallas, TX 75240 | Oil & Gas Operator | Mar 2015 |
| 94 | Bta Oil Producers, LLC | Midland, TX 79701 | Oil & Gas Operator | Dec 2024 |
| 95 | Burk Royalty Co., LTD. | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 2024 |
| 96 | Burlington Resources Oil & Gas Company L | Gillette, WY 82718 | Oil & Gas Operator | Jan 2022 |
| 97 | Burnett Oil Co Inc | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2024 |
| 98 | Bwab Incorporated | Denver, CO 80202 | Oil & Gas Operator | Aug 1996 |
| 99 | BXP Operating, LLC | Houston, TX 77079 | Oil & Gas Operator | Dec 2024 |
| 100 | C & H Well Servicing Inc | Gillette, WY 82717 | Oil & Gas Operator | Nov 2024 |