| 401 | Ramco Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2006 |
| 402 | Ranch Oil Company | West Linn, OR 97068 | Oil & Gas Operator | Jun 2026 |
| 403 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 404 | Range Production Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2026 |
| 405 | Rasmussen, Hal J. Operating, Inc | Midland, TX 79701 | Oil & Gas Operator | Apr 2009 |
| 406 | Raydon Exploration, Inc. | Oklahoma City, OK 73118 | Oil & Gas Operator | Jul 2026 |
| 407 | Redline Energy LLC | Dover, OK 73734 | Oil & Gas Operator | May 2026 |
| 408 | Republic Energy Inc. | Decatur, TX 76234 | Oil & Gas Operator | Dec 2016 |
| 409 | Reserve Management, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jul 2026 |
| 410 | Resource Oil And Gas, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Jul 2026 |
| 411 | Revelation Resources | Cypress, TX 77410-2578 | Oil & Gas Operator | Apr 2026 |
| 412 | Ricks Exploration Co | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 413 | Rio Petroleum, Inc. | Amarillo, TX 79102 | Oil & Gas Operator | Jul 2026 |
| 414 | Rives Owen H | Holdenville, OK 74848-0913 | Oil & Gas Operator | Nov 2000 |
| 415 | Riviera Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2026 |
| 416 | RKK Production Company | Mustang, OK 73064 | Oil & Gas Operator | May 2026 |
| 417 | Robinowitz Oil Company | Tulsa, OK 74136-1429 | Oil & Gas Operator | Feb 2023 |
| 418 | Rosewood Resources Inc | Dallas, TX 75201 | Oil & Gas Operator | Jul 2026 |
| 419 | RTC Resources, LLP | Weatherford, OK 73096 | Oil & Gas Operator | Jul 2026 |
| 420 | Rupe Oil Company Inc | Wichita, KS 67278 | Oil & Gas Operator | Mar 2026 |
| 421 | Sabre Operating, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2026 |
| 422 | Sage Drilling Co Inc | Wichita, KS 67202 | Oil & Gas Operator | Nov 1998 |
| 423 | Sage Energy Company | San Antonio, TX 78215 | Oil & Gas Operator | Jul 2026 |
| 424 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 425 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2026 |
| 426 | Sandia Operating Corp. | San Antonio, TX 78270 | Oil & Gas Operator | May 2010 |
| 427 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Jul 2026 |
| 428 | Santa Fe Minerals, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Sep 2013 |
| 429 | Scarth Oil & Gas Co | Amarillo, TX 79101 | Oil & Gas Operator | Feb 1999 |
| 430 | Schmid Properties, Inc. | Hico, TX 76457 | Oil & Gas Operator | Jul 2026 |
| 431 | Scout Energy Management LLC | Dallas, TX 75240 | Oil & Gas Operator | Jul 2026 |
| 432 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 433 | Seagull Mid-South Inc | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 434 | Seagull Midcon Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 435 | Select Exploration Group LLC | Eufaula, OK 74432 | Oil & Gas Operator | May 2024 |
| 436 | Seneca Oil Company | Tulsa, OK 74121-1518 | Oil & Gas Operator | Jan 2015 |
| 437 | Sensor Oil & Gas, Inc. | Duncan, OK 73534 | Oil & Gas Operator | May 2013 |
| 438 | Service Drilling Co. | Tulsa, OK 74119 | Oil & Gas Operator | Oct 1998 |
| 439 | Service Drilling Co., L.L.C. | Tulsa, OK 74119 | Oil & Gas Operator | Oct 2003 |
| 440 | Seven J Oil Inc | Jenning, OK 74038-9729 | Oil & Gas Operator | Feb 2026 |
| 441 | Shell Western Expl & Prod Inc | Houston, TX 77251 | Oil & Gas Operator | Mar 2015 |
| 442 | Shields Cooper | Bonita Springs, FL 34135-3421 | Oil & Gas Operator | Jan 2011 |
| 443 | Slawson Donald C | Wichita, KS 67202 | Oil & Gas Operator | Oct 2025 |
| 444 | SM Energy Company | Midland, TX 79707 | Oil & Gas Operator | Jul 2026 |
| 445 | Snyder Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2015 |
| 446 | Snyder Partners | Cody, WY 82414 | Oil & Gas Operator | Apr 2026 |
| 447 | Sorrels J R Dba Cheyenne Oil Properties | Ponca City, OK 74601 | Oil & Gas Operator | Jul 2022 |
| 448 | Southern Star Central Gas Pipeline Inc | Owensboro, KY 42301 | Oil & Gas Operator | Mar 2026 |
| 449 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 450 | Southport Exploration Inc | Tulsa, OK 74103-4015 | Oil & Gas Operator | Nov 1998 |
| 451 | Sparks Petroleum Company | Oklahoma City, OK 73128 | Oil & Gas Operator | Mar 1998 |
| 452 | Sparks Resources Inc | Bristow, OK 74010 | Oil & Gas Operator | May 2026 |
| 453 | Spess Oil Company Inc | Cleveland, OK 74020-4617 | Oil & Gas Operator | May 2026 |
| 454 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 455 | Stallion Energy, Inc. | Houston, TX 77060 | Oil & Gas Operator | Oct 2017 |
| 456 | Stephens Production Company | The Woodlands, TX 77381 | Oil & Gas Operator | May 2026 |
| 457 | Stinger Oil & Gas Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Oct 2013 |
| 458 | Strat Land Exploration Company | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2026 |
| 459 | Strike Axe Oil And Gas Corporation | | Oil & Gas Operator | Mar 2021 |
| 460 | Sullivan & Co. | Tulsa, OK 74114 | Oil & Gas Operator | May 2022 |
| 461 | Sullivan And Company LLC | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2026 |
| 462 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Jul 2026 |
| 463 | Sundown Energy, Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 464 | Sunlight Exploration, Inc. | Canyon, TX 79015 | Oil & Gas Operator | Jul 2026 |
| 465 | Sunterra Energy Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2009 |
| 466 | Superior Midstream, LLC | Tulsa, OK 74170 | Oil & Gas Operator | Feb 2020 |
| 467 | Sweetwater Exploration LLC | Norman, OK 73069-5636 | Oil & Gas Operator | Apr 2026 |
| 468 | Swenton Michael J | Tulsa, OK 74105 | Oil & Gas Operator | Apr 2026 |
| 469 | SWN Production LLC | Spring, TX 77389-4954 | Oil & Gas Operator | Feb 2022 |
| 470 | T E L Oil & Gas Corporation | Guymon, OK 73941 | Gas Operator | Apr 2026 |
| 471 | T-Y Development Corp | Perryton, TX 79070 | Oil & Gas Operator | Jul 2026 |
| 472 | Taylor Energy Corporation | Amarillo, TX 79114 | Oil & Gas Operator | Feb 1999 |
| 473 | Taylor R C Companies Inc | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | May 2021 |
| 474 | Tbi Exploration Inc | Englewood, CO 801556525 | Oil & Gas Operator | Jun 2011 |
| 475 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Dec 2025 |
| 476 | Tessera Energy LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Apr 2026 |
| 477 | Texaco Exploration & Prod Inc | Houston, TX 77236 | Oil & Gas Operator | Mar 2026 |
| 478 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 479 | Texas Energies Inc | Pratt, KS 67124 | Oil & Gas Operator | Aug 1998 |
| 480 | Texas Oil & Gas Corporation | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 481 | Thomas J L Engineering Inc | Edmond, OK 73003-0026 | Oil & Gas Operator | Jul 2016 |
| 482 | Tidemark Exploration | Tulsa, OK 74170 | Oil & Gas Operator | May 2005 |
| 483 | Titan Resources LTD | Limaville, OH 44640 | Oil & Gas Operator | May 2026 |
| 484 | Transcontinental Company | Haltom City, TX 76148-4122 | Oil & Gas Operator | May 2026 |
| 485 | Transpetco Transport Company | Shreveport, LA 71101-5370 | Oil Operator | Jun 2008 |
| 486 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Jul 2026 |
| 487 | Trey Resources Inc. | Midland, TX 79710 | Oil & Gas Operator | Apr 2026 |
| 488 | Trueblood Resources, Inc. | Denver, CO 80222 | Oil & Gas Operator | Jul 2026 |
| 489 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 490 | Txok Energy Resources Company | Tulsa, OK 74172-0140 | Oil & Gas Operator | Feb 2017 |
| 491 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 492 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 493 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | Mar 2026 |
| 494 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Jul 2026 |
| 495 | Upland Resources, Inc. | Canadian, TX 79014 | Oil & Gas Operator | Dec 2009 |
| 496 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Jul 2026 |
| 497 | Vantage Point Operating Co. | Houston, TX 77057 | Oil & Gas Operator | Dec 2014 |
| 498 | Veenker Resources Inc | Oklahoma City, OK 73113 | Oil & Gas Operator | May 2026 |
| 499 | Vega Energy Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 2015 |
| 500 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Apr 2026 |