| 12501 | Hammerschmidt, Leo | Plainville, KS 67663 | Oil Operator | Aug 2000 |
| 12502 | Hammerschmidt, William E | Plainville, KS 67663 | Oil Operator | Sep 2025 |
| 12503 | Hammersmith, Beverly | West Falls, NY 14170 | Gas Operator | Dec 2024 |
| 12504 | Hammon Properties | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 1996 |
| 12505 | Hammond Valley Colony, Inc. | Harlowton, MT 59036 | Gas Operator | Dec 2025 |
| 12506 | Hamon Jake L | Dallas, TX 75201-3902 | Oil & Gas Operator | Nov 1997 |
| 12507 | Hamon Oil Company | | Oil & Gas Operator | Aug 1985 |
| 12508 | Hamon Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2011 |
| 12509 | Hamp Oil | Ponca City, OK 74604 | Oil & Gas Operator | Sep 2002 |
| 12510 | Hamp Oil - Pace | | Oil & Gas Operator | Apr 1994 |
| 12511 | Hampton Corporation (The) | Norman, OK 73069-5910 | Oil Operator | Jun 2016 |
| 12512 | Hampton Oil & Gas | Early, TX 76802 | Gas Operator | Feb 2012 |
| 12513 | Hampton Resources Corporation | Houston, TX 77010 | Oil & Gas Operator | Mar 1996 |
| 12514 | Hampton, Jno. W. & Son | Wichita Falls, TX 76302 | Oil & Gas Operator | Nov 1998 |
| 12515 | Hanaco Operating | Holliday, TX 76366 | Oil Operator | Mar 2008 |
| 12516 | Hanaco, LLC | Holliday, TX 76366 | Oil Operator | Dec 2017 |
| 12517 | Hanagan Petroleum Corp | Roswell, NM 88201 | Oil & Gas Operator | Sep 1999 |
| 12518 | Hancock Leon | Kingston, OK 73439-9618 | Oil Operator | Dec 2014 |
| 12519 | Hancock, Burton W | Morrison, CO 80465 | Oil & Gas Operator | Dec 2017 |
| 12520 | Hand Oil Co. | Chanute, KS 66720 | Oil Operator | Nov 2000 |
| 12521 | Handy, Daniel G. | East Aurora, NY 14052 | Gas Operator | Dec 2024 |
| 12522 | Hane Operating, Inc. | Santa Anna, TX 76878 | Oil & Gas Operator | Sep 2005 |
| 12523 | Hanger Oil, L.L.C. | Wichita Falls, TX 76308 | Oil & Gas Operator | Mar 2026 |
| 12524 | Hank Oil & Gas, Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2023 |
| 12525 | Hankamer, Curtis Corporation,The | Houston, TX 77024 | Oil & Gas Operator | Mar 2026 |
| 12526 | Hankey Oil Company | Houston, TX 77027 | Oil & Gas Operator | Feb 2010 |
| 12527 | Hankey Operating, Inc. | Houston, TX 77027 | Oil & Gas Operator | Mar 2016 |
| 12528 | Hanks, Christopher Glenn | Gainesville, TX 76240 | Oil & Gas Operator | Mar 2026 |
| 12529 | Hanley & Bird Inc | Tulsa, OK 74119 | Oil & Gas Operator | Dec 2011 |
| 12530 | Hanley Petroleum Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2017 |
| 12531 | Hanna M A Co | Cleveland, OH 44114-1824 | Oil & Gas Operator | Dec 1991 |
| 12532 | Hanna Oil And Gas Company | Fort Smith, AR 72901 | Oil & Gas Operator | Dec 2025 |
| 12533 | Hannathon Petroleum II, LLC | Midland, TX 79705 | Oil & Gas Operator | Mar 2026 |
| 12534 | Hannathon Petroleum, LLC | Midland, TX 79705 | Oil & Gas Operator | Mar 2026 |
| 12535 | Hannis Operating, LLC | Olney, TX 76374 | Oil & Gas Operator | Mar 2026 |
| 12536 | Hannold, Allan & Yolanda | Bloomfield, NY 14469 | Gas Operator | Dec 2024 |
| 12537 | Hanoco Inc | Tulsa, OK 74135 | Oil & Gas Operator | Dec 2025 |
| 12538 | Hanover Management Company | | Oil Operator | Aug 1979 |
| 12539 | Hanover Operating Company | Tulsa, OK 74101 | Oil & Gas Operator | Dec 1998 |
| 12540 | Hanselman, Michael D. | Jamestown, NY 14701 | Gas Operator | Dec 2024 |
| 12541 | Hansen Dane G TR | | Oil Operator | Feb 1995 |
| 12542 | Hansen Noel | Avant, OK 74001 | Oil Operator | Aug 2013 |
| 12543 | Hansen Oil Corporation | Shreveport, LA 71106 | Oil Operator | Apr 2003 |
| 12544 | Hansen, Dane G. - Trust | Logan, KS 67646 | Oil Operator | Oct 2013 |
| 12545 | Hanshu Production Company | Darrouzett, TX 79024 | Oil & Gas Operator | Apr 2017 |
| 12546 | Hanshu Production Company, LLC | Nashville, TN 37215 | Gas Operator | Mar 2026 |
| 12547 | Hanson Corporation | New Braunfels, TX 78132 | Oil & Gas Operator | Mar 2008 |
| 12548 | Hanson Energy | Glencoe, NM 88324 | Oil & Gas Operator | Jul 2008 |
| 12549 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 12550 | Hanson Natural Resources Co. | | Oil & Gas Operator | Nov 1991 |
| 12551 | Hanson Operating Company Inc | Roswell, NM 88202 | Oil & Gas Operator | Dec 2025 |
| 12552 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 12553 | Hanvey Production Co., Inc. | Roanoke, TX 76262 | Oil & Gas Operator | Nov 2012 |
| 12554 | Hanvey, Don H. Oil Interests Inc | Cisco, TX 76437 | Oil & Gas Operator | Mar 2026 |
| 12555 | Happy Hill Operating LLC | Guthrie, OK 73044-7361 | Oil & Gas Operator | Oct 2017 |
| 12556 | Har Ken Oil Company | | Oil & Gas Operator | Dec 2021 |
| 12557 | Har-Ken Agent Ok, LTD | Owensboro, KY 42302 | Oil & Gas Operator | Dec 2023 |
| 12558 | Har-Ken Agent, Ok | Owensboro, KY 42302 | Oil Operator | Sep 2025 |
| 12559 | Harbacek Florence | Holyrood, KS 67450 | Oil Operator | Aug 2002 |
| 12560 | Harbert Energy Corp | Irving, TX 75015-2510 | Oil & Gas Operator | Feb 1993 |
| 12561 | Harbert Energy Corp/Gulf Coast | | Oil & Gas Operator | Dec 1991 |
| 12562 | Harbor Operating, LLC | | Oil & Gas Operator | Dec 1999 |
| 12563 | Harbor Petroleum, LLC | Granbury, TX 76049 | Oil & Gas Operator | Mar 2026 |
| 12564 | Harbor Resources LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Mar 2026 |
| 12565 | Harborcreek SCH Dist | Harborcreek, PA 16421-1606 | Oil & Gas Operator | Dec 2025 |
| 12566 | Harburg* Rudolph W | | Oil & Gas Operator | Nov 2022 |
| 12567 | Harco Land, Inc. | Dallas, TX 75230 | Oil & Gas Operator | Aug 1996 |
| 12568 | Harcon Energy, LLC | Le Roy, KS 66857 | Oil Operator | Dec 2009 |
| 12569 | Harcor Energy Inc. | | Gas Operator | Dec 1999 |
| 12570 | Harcor Exploration Inc. | | Oil Operator | Aug 1989 |
| 12571 | Hard Rock DRLG Co | Falls Of Rough, KY 40119 | Oil Operator | Dec 2023 |
| 12572 | Hard Rock Exploration, Inc. | | Oil & Gas Operator | Dec 2008 |
| 12573 | Hard Rock Operating LLC | | Oil & Gas Operator | May 2022 |
| 12574 | Hardco Inc | Cleveland, OH 44115 | Oil & Gas Operator | Dec 1992 |
| 12575 | Hardee Oil Co. | | Oil Operator | Dec 1994 |
| 12576 | Hardee Petroleum Co., A General PTSHP. | | Oil & Gas Operator | Dec 2013 |
| 12577 | Harden Operating Company Inc | Tulsa, OK 74106-2722 | Oil & Gas Operator | Sep 2006 |
| 12578 | Hardesty Production | Gambier, OH 43022 | Oil & Gas Operator | Dec 2024 |
| 12579 | Hardey Co., The | Shreveport, LA 71107 | Oil & Gas Operator | Mar 2026 |
| 12580 | Hardey Production Company | | Oil Operator | Dec 1998 |
| 12581 | Hardin Energy Co., Inc. | Bigfoot, TX 78005 | Oil Operator | Mar 2026 |
| 12582 | Hardin Hanley E | Zanesville, OH 43701 | Oil & Gas Operator | Dec 1995 |
| 12583 | Hardin Oil Co. | | Oil Operator | Dec 2019 |
| 12584 | Hardin Productions | Okemah, OK 74859 | Oil & Gas Operator | Dec 2006 |
| 12585 | Hardin, W.V. Estate | San Antonio, TX 78258 | Oil & Gas Operator | Apr 2002 |
| 12586 | Harding & Shelton Inc | Oklahoma City, OK 73104-2410 | Oil & Gas Operator | Dec 2025 |
| 12587 | Harding And Shelton Exploration LLC | Oklahoma City, OK 73101-1557 | Oil & Gas Operator | Nov 2025 |
| 12588 | Harding Company | Dallas, TX 75244 | Oil & Gas Operator | Jan 2015 |
| 12589 | Harding Exploration, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 2016 |
| 12590 | Harding Well Service Co. | Coahoma, TX 79511 | Oil & Gas Operator | Aug 2003 |
| 12591 | Hardrock Oil Company | Great Falls, MT 59403 | Gas Operator | Nov 2025 |
| 12592 | Hardrock Operating Company, Inc. | Fort Worth, TX 76161 | Oil & Gas Operator | Mar 2026 |
| 12593 | Hardrock Resources Inc. | Winters, TX 79567 | Oil & Gas Operator | Mar 2026 |
| 12594 | Hardway Prod & Operating, LLC | Abilene, TX 79608 | Oil & Gas Operator | Aug 2016 |
| 12595 | Hardwick Oil Company | Sugar Land, TX 77478 | Oil & Gas Operator | Nov 2014 |
| 12596 | Hardwick, Mark P. Inc. | Midland, TX 79702 | Oil & Gas Operator | Nov 1994 |
| 12597 | Hardwick, Ross H. Oil Company | Devine, TX 78016 | Oil & Gas Operator | Mar 2026 |
| 12598 | Hardy And Hardy Consulting LLC | | Oil & Gas Operator | Nov 2025 |
| 12599 | Hardy Oil & Gas USA Inc. | Houston, TX 77079 | Oil & Gas Operator | Jun 1996 |
| 12600 | Hardy Ranch, Inc. | Henderson, TX 75654 | Oil & Gas Operator | Mar 2026 |