| 501 | Oak Hills Drilling & Oper., LLC | Holdenville, OK 74848 | Oil & Gas Operator | May 2013 |
| 502 | Oak Hills Energy Inc | Holdenville, OK 74848-0470 | Oil & Gas Operator | Sep 2014 |
| 503 | Oak Tree Natural Res LLC | Oklahoma City, OK 73120-5065 | Oil & Gas Operator | Mar 2015 |
| 504 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2026 |
| 505 | Ochiltree Oil Company | Edmond, OK 73034 | Oil & Gas Operator | Apr 2020 |
| 506 | Octagon Resources LLC | Norman, OK 73071-1295 | Oil & Gas Operator | May 2015 |
| 507 | Oil Center Operating Inc | Fort Worth, TX 76102-5108 | Oil & Gas Operator | Apr 2014 |
| 508 | Oil Exploration Of America Inc | Sisseton, SD 57262-9503 | Oil & Gas Operator | Jun 2001 |
| 509 | Oil Production Management Inc | Squaw Valley, CA 93675-9725 | Oil & Gas Operator | Dec 2002 |
| 510 | Okc Energy Corporation | Oklahoma City, OK 73120-3119 | Oil & Gas Operator | Nov 2014 |
| 511 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2026 |
| 512 | Oklahoma Basic Economy Corp | Houston, TX 77002-6003 | Oil & Gas Operator | Apr 2020 |
| 513 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Apr 2026 |
| 514 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Apr 2026 |
| 515 | Oklahoma Prime Energy LLC | Ardmore, OK 73401 | Oil Operator | May 2020 |
| 516 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 517 | Oliphant Gertrud | Holdenville, OK 74848-0849 | Oil Operator | Aug 2013 |
| 518 | On-Line Oil Inc | Oklahoma City, OK 73105-5208 | Oil & Gas Operator | Mar 2015 |
| 519 | Opubco Resources Of TX Inc | Dallas, TX 75231 | Oil & Gas Operator | Sep 2005 |
| 520 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | May 2026 |
| 521 | Outback Petroleum Inc | Moore, OK 73160-9998 | Oil & Gas Operator | Mar 2015 |
| 522 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Jul 2026 |
| 523 | P & C Oil Company | Leona, TX 75850 | Oil & Gas Operator | May 2026 |
| 524 | P & H Construction Inc | Wewoka, OK 74884 | Oil & Gas Operator | Mar 2026 |
| 525 | P K & L Oil Properties | Shawnee, OK 74802-0931 | Oil & Gas Operator | Mar 2001 |
| 526 | P-2 Exploraton Co Inc | Pampa, TX 79065-2920 | Oil & Gas Operator | Jun 1996 |
| 527 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 528 | Page Petroleum Inc | Calgary, AB T2P3M-3000 | Oil & Gas Operator | Nov 1998 |
| 529 | Paluca Petroleum Inc. | Holdenville, OK 74848 | Oil & Gas Operator | Apr 2026 |
| 530 | Pan Western Energy Corporation | Tulsa, OK 74114 | Oil & Gas Operator | Jul 2026 |
| 531 | Panhandle Eastern Pipeline Company LP | Houston, TX 77002-6803 | Oil & Gas Operator | Oct 1999 |
| 532 | Par Oil Company Inc | Denver, CO 80201 | Oil & Gas Operator | Jun 2003 |
| 533 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 534 | Parkinsol Oil Company | Seminole, OK 74868-1648 | Oil & Gas Operator | Oct 2014 |
| 535 | Parks Bill M | Seminole, OK 74818-1648 | Oil & Gas Operator | Apr 2014 |
| 536 | Parrish Jr W F | Ardmore, OK 73401-2941 | Oil & Gas Operator | Feb 2025 |
| 537 | Parsons Engineering Corporation | Tulsa, OK 74137-7505 | Oil & Gas Operator | Oct 2017 |
| 538 | Patco Investments Inc | Seminole, OK 74868 | Oil Operator | Nov 2007 |
| 539 | Patina Oklahoma Corp | Duncan, OK 73533-9523 | Oil & Gas Operator | Nov 2014 |
| 540 | Patterson George E | Ada, OK 74820-1108 | Oil & Gas Operator | Jul 2016 |
| 541 | Patterson John H | Shawnee, OK 74801 | Oil Operator | Dec 2006 |
| 542 | Patterson Oil Company, The | Eastland, TX 76448 | Oil & Gas Operator | Apr 2026 |
| 543 | Patterson Russell B | Wewoka, OK 74884-1262 | Oil & Gas Operator | Feb 2020 |
| 544 | Paul Gillham Oil Company | Maud, OK 74854 | Oil & Gas Operator | Apr 2026 |
| 545 | Pawnee Petroleum Company | Seminole, OK 74868-0951 | Oil & Gas Operator | Feb 2023 |
| 546 | Pegg Oil LLC | Allen, OK 74825-4900 | Oil Operator | Aug 2022 |
| 547 | Pelican Production Company | New Orleans, LA 70130-2477 | Oil & Gas Operator | Mar 2014 |
| 548 | Pemco LLC | Skiatook, OK 74070 | Oil Operator | Apr 2026 |
| 549 | Pennant Oil & Gas LLC | Oklahma City, OK 73159-6905 | Oil & Gas Operator | Jan 2024 |
| 550 | Petra Petroleum Inc | Littleton, CO 80160-0319 | Oil & Gas Operator | Jun 2005 |
| 551 | Petro Speed Inc | Norman, OK 73069-8116 | Oil & Gas Operator | Mar 2015 |
| 552 | Petroleum Exploration Company LTD LP | Breckenridge, TX 76424 | Oil & Gas Operator | May 2026 |
| 553 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 2026 |
| 554 | Petroleum Resources Co | Wichita, KS 67206 | Oil & Gas Operator | May 2000 |
| 555 | Petroquest Energy, L.L.C. | Lafayette, LA 70505 | Oil & Gas Operator | Jul 2026 |
| 556 | Petroquest Oil & Gas LLC | Wewoka, OK 74884 | Oil & Gas Operator | May 2026 |
| 557 | Phase III Drilling Inc | Wetumka, OK 74883-0333 | Oil & Gas Operator | Mar 2026 |
| 558 | Phillips Jr N J | Seminole, OK 74868-2828 | Oil Operator | Jul 1998 |
| 559 | Philpot Operating Company Inc | Ada, OK 74820-4457 | Oil & Gas Operator | May 2013 |
| 560 | Phoenix Oil & Gas Inc | Seminole, OK 74868 | Oil & Gas Operator | May 2025 |
| 561 | Pierco Energy Corp. | Dallas, TX 75231 | Oil & Gas Operator | Jul 2026 |
| 562 | Pilgrim & Smith Inc | Tulsa, OK 74152 | Oil & Gas Operator | Apr 2015 |
| 563 | Pinnacle Corporation (The) | Broken Arrow, OK 74012 | Oil & Gas Operator | Nov 2014 |
| 564 | Pittencrieff America Inc | Abilene, TX 79608 | Oil & Gas Operator | Feb 2003 |
| 565 | PM Oil & Gas, Inc. | San Angelo, TX 76903 | Oil Operator | Jul 2026 |
| 566 | Pogue Randall | Ada, OK 74821-1547 | Oil & Gas Operator | Apr 2014 |
| 567 | Pontotoc Operations Inc | Dallas, TX 75225-1425 | Oil & Gas Operator | Jun 2017 |
| 568 | Postrock Midcontinent Production LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Apr 2026 |
| 569 | Pre-MC Inc | Allen, OK 74825 | Oil & Gas Operator | Apr 2026 |
| 570 | Premier Resources LTD | Denver, CO 80237 | Oil & Gas Operator | Jul 2002 |
| 571 | Prentice Bro Oil Operators | Allen, OK 74825 | Oil & Gas Operator | Apr 2014 |
| 572 | Presley Operating LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 573 | Presley Petroleum Company | Newport Beach, CA 92658-2200 | Oil & Gas Operator | Oct 1999 |
| 574 | Producers Oil Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2007 |
| 575 | Pryor VIctor W Jr | Holdenville, OK 74848 | Oil & Gas Operator | Apr 2017 |
| 576 | Pumping Services Inc | Seminole, OK 74868-2421 | Oil & Gas Operator | Jul 2025 |
| 577 | Q T Oil LTD Co | Shawnee, OK 74801 | Oil Operator | Apr 2026 |
| 578 | Quench Oil & Gas Inc | Plano, TX 75075-2902 | Oil & Gas Operator | Apr 2009 |
| 579 | Quest Cherokee LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2026 |
| 580 | R & C Oil And Gas Inc | Ada, OK 74820-3150 | Oil Operator | Jul 2016 |
| 581 | R Baker Oil LLC | Okemah, OK 74859 | Oil & Gas Operator | May 2026 |
| 582 | R H S Inc | Ada, OK 74821-1252 | Oil & Gas Operator | Apr 2020 |
| 583 | R J Exploration LLC | Konawa, OK 74849 | Oil & Gas Operator | May 2026 |
| 584 | R K R Exploration | Seminole, OK 74868-9754 | Oil & Gas Operator | Mar 2015 |
| 585 | R W Production Company Inc | Ada, OK 74821-2693 | Oil & Gas Operator | Apr 2011 |
| 586 | Radford Dale | Konawa, OK 74849 | Oil & Gas Operator | Apr 2026 |
| 587 | Rainbow Energy Inc | | Oil & Gas Operator | Jul 2024 |
| 588 | Rainmaker Oil & Gas Corp | Oklahoma City, OK 73112-8883 | Oil & Gas Operator | Apr 2015 |
| 589 | Raizen Oil Company | Velma, OK 73091 | Oil & Gas Operator | Feb 2016 |
| 590 | Ramhead Petroleum Inc | Seminole, OK 74818-0848 | Oil & Gas Operator | Aug 2008 |
| 591 | Ramsey Property MGMT Inc | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Mar 2019 |
| 592 | Randy And Jan Walker Oil Company LLC | Konawa, OK 74849-9333 | Oil & Gas Operator | May 2026 |
| 593 | Ravil Inc | Edmond, OK 73013 | Gas Operator | Nov 1998 |
| 594 | Rawhide Oil Company | | Oil & Gas Operator | Sep 2011 |
| 595 | Rayland Operating LLC | Moro, IL 62067 | Oil Operator | Jun 2023 |
| 596 | Reach Oil And Gas Company Inc | Oklahoma City, OK 73118-1100 | Oil & Gas Operator | Apr 2026 |
| 597 | Reames Jr Keith E | Duncan, OK 73534-0246 | Oil & Gas Operator | Jul 1999 |
| 598 | Red River Oil & Gas Company | Oklahoma City, OK 73132-5120 | Oil & Gas Operator | Mar 2015 |
| 599 | Red Rock Resources, L.L.C. | Wichita Falls, TX 76310 | Oil & Gas Operator | Apr 2026 |
| 600 | Red Rocks Oil & Gas Operating LLC | Oklahoma City, OK 73103 | Oil & Gas Operator | May 2026 |