| 1 | H & D Operating Company | Refugio, TX 78377 | Oil & Gas Operator | May 2015 |
| 2 | H & H Oil Productions | Tulsa, OK 74145 | Oil Operator | Jul 1999 |
| 3 | H & M Resources LLC | Dallas, TX 75225 | Oil & Gas Operator | Sep 2025 |
| 4 | H L L Inc | Scottsdale, AZ 85251 | Oil & Gas Operator | Jan 2007 |
| 5 | H.L.S. Energy Co., Inc. | Uvalde, TX 78801 | Oil & Gas Operator | Aug 2003 |
| 6 | Hadson Petro USA Inc | | Oil & Gas Operator | Nov 2016 |
| 7 | Hail Petroleum Corporation | Garland, TX 75047-5036 | Oil Operator | Mar 1997 |
| 8 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Nov 2018 |
| 9 | Halgas Inc | Tulsa, OK 74101-3012 | Oil & Gas Operator | May 2013 |
| 10 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 11 | Hallmark Resources, Inc | Stilwell, OK 74960-0312 | Oil & Gas Operator | Sep 2020 |
| 12 | Hamil Oil & Gas LLC | Kingfisher, OK 73750-6500 | Oil & Gas Operator | May 2025 |
| 13 | Hanoco Inc | Tulsa, OK 74135 | Oil & Gas Operator | May 2025 |
| 14 | Har-Ken Oil Co | | Oil & Gas Operator | Dec 2021 |
| 15 | Harden Operating Company Inc | Tulsa, OK 74106-2722 | Oil & Gas Operator | Sep 2006 |
| 16 | Hardwick Oil Company | Sugar Land, TX 77478 | Oil & Gas Operator | Nov 2014 |
| 17 | Harris Mildred C | Tulsa, OK 74120 | Oil & Gas Operator | Mar 2025 |
| 18 | Hartline Tom | Drumright, OK 74030 | Oil Operator | Mar 2025 |
| 19 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 20 | Heath Oil Co., Inc. | Washington, OK 73093-4702 | Oil & Gas Operator | May 2025 |
| 21 | Heinrich Production Co Inc | Lubbuck, TX 79424 | Oil Operator | Dec 2024 |
| 22 | Hellard Elmer J | Sapulpa, OK 74066 | Oil & Gas Operator | Jun 2025 |
| 23 | Helmco LTD | Kiefer, OK 74041-0397 | Oil & Gas Operator | Jan 2007 |
| 24 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | May 2025 |
| 25 | Henderson Exploration Company | Tulsa, OK 74120 | Oil & Gas Operator | May 2013 |
| 26 | Henry Oil & Gas Inc | Oklahoma City, OK 73127 | Oil & Gas Operator | Jul 2009 |
| 27 | Henry Petroleum Inc | Oklahoma City, OK 73162-1757 | Oil & Gas Operator | Sep 2019 |
| 28 | Henry Wat Oil Company | Tulsa, OK 74101 | Oil Operator | Jan 2014 |
| 29 | Henson Doyle | Okmulgee, OK 74447-4841 | Oil & Gas Operator | Jun 2020 |
| 30 | Henson Terry Dba Daycon Exploration | Tulsa, OK 74137-3546 | Oil & Gas Operator | May 2025 |
| 31 | Heuston Oil LLC | Bartlesville, OK 74006 | Oil & Gas Operator | Apr 2020 |
| 32 | High Energy | Cushing, OK 74023 | Oil & Gas Operator | May 2025 |
| 33 | Hightower Energy LLC | Cushing, OK 74023-6370 | Oil & Gas Operator | Jun 2025 |
| 34 | Hightower Oil & Gas | Cairo, IL 62914-0401 | Oil Operator | Nov 2014 |
| 35 | Hill Gilford | Stroud, OK 74079-9401 | Oil & Gas Operator | May 2013 |
| 36 | Hill William H | Broken Arrow, OK 74012-8952 | Oil & Gas Operator | Apr 2020 |
| 37 | Hinson Bobbie L | Bristow, OK 74010 | Oil & Gas Operator | Jun 2025 |
| 38 | Hinson Jr Bobbie L | Bristow, OK 74010 | Oil & Gas Operator | Jul 2020 |
| 39 | HLH Realty Co | Drumright, OK 74030 | Oil & Gas Operator | Mar 2016 |
| 40 | Holloway David A | Okmulgee, OK 74447-9191 | Oil & Gas Operator | May 2025 |
| 41 | Holman Kendall | Paden, OK 74860-7116 | Oil & Gas Operator | Jun 2025 |
| 42 | Holmes Mary Ellen | Bristow, OK 74010 | Oil Operator | Mar 2015 |
| 43 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 44 | Hope Oil Inc | Midland, TX 79702 | Oil & Gas Operator | Oct 2021 |
| 45 | Hoppes Helen E | Depew, OK 74028-3428 | Oil & Gas Operator | Apr 2015 |
| 46 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 47 | Horn Eddie L Dba B & E Investments | Bristow, OK 74010 | Oil & Gas Operator | May 2025 |
| 48 | Horn Oil Company | Bristow, OK 74010 | Oil & Gas Operator | May 2025 |
| 49 | Houseco Petroleum Inc | Bristow, OK 74010-0842 | Oil & Gas Operator | Aug 2002 |
| 50 | Hoyt Oil & Gas LLC | Cushing, OK 74023-0442 | Oil & Gas Operator | Apr 2025 |
| 51 | HRC Production Co | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 52 | Huitt Joe A | Tulsa, OK 74103 | Oil & Gas Operator | May 2001 |
| 53 | Huitt Joe A Rev Trust | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2009 |
| 54 | Hull Oil Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Sep 2021 |
| 55 | Hunt Brothers Producing Co Inc | Redding, CA 96049-2516 | Oil & Gas Operator | Sep 2012 |
| 56 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 2025 |
| 57 | Hydrocarbon Technology Services | | Oil & Gas Operator | Dec 2000 |
| 58 | Hyperion Energy LP | Dallas, TX 75206 | Oil & Gas Operator | May 2014 |