| 401 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Apr 2024 |
| 402 | Pacific Operators, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | Mar 1999 |
| 403 | Panhandle Producing Company | San Antonio, TX 78205 | Oil & Gas Operator | Oct 1993 |
| 404 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 405 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 406 | Pathfinder Exploration LLC | Norman, OK 73069-8516 | Gas Operator | Nov 2008 |
| 407 | Peak Energy Corporation | Plano, TX 75093 | Oil & Gas Operator | Oct 2018 |
| 408 | Pearl, Bill H. Productions, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Apr 2024 |
| 409 | Pedeco, Inc. | Casper, WY 82601 | Oil & Gas Operator | Mar 2008 |
| 410 | Pennzenergy Exp. & Prod., L.L.C. | Houston, TX 77210 | Oil & Gas Operator | Mar 2000 |
| 411 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 412 | Peoples Energy Prod.-TX, L.P. | Houston, TX 77002 | Oil & Gas Operator | Sep 2007 |
| 413 | Perdido Energy, LLC | Houston, TX 77251 | Oil & Gas Operator | Apr 2024 |
| 414 | Petro-Hunt Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2003 |
| 415 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2024 |
| 416 | Petro-Smith Operating LLC | Houston, TX 77005 | Oil & Gas Operator | Apr 2024 |
| 417 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 418 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Apr 2024 |
| 419 | Petropoint Energy Operating, LLC | Houston, TX 77098 | Oil & Gas Operator | Apr 2024 |
| 420 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 421 | Phoenix Fund, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Jun 2000 |
| 422 | Phoenix Operating Company Of TX. | Dallas, TX 75206 | Oil & Gas Operator | Jun 1995 |
| 423 | Pierce Junction Petroleum Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2010 |
| 424 | Pierco Energy Corp. | Dallas, TX 75231 | Oil & Gas Operator | Apr 2024 |
| 425 | Pinon Corporation | San Antonio, TX 78266 | Oil & Gas Operator | Jul 2001 |
| 426 | Pintail Production Co., Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | Apr 2024 |
| 427 | Pioneer Natural Res. USA, Inc. | Irving, TX 75038 | Oil & Gas Operator | Apr 2024 |
| 428 | Pioneer Resources Producing, L.P | Irving, TX 75039 | Oil & Gas Operator | Feb 2001 |
| 429 | Plains Exploration & Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Jul 2013 |
| 430 | Plains Marketing LP | Cushing, OK 74023 | Oil & Gas Operator | Dec 2022 |
| 431 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 432 | Pogo Producing Company LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2024 |
| 433 | Precio Energy, LLC | Beaumont, TX 77726 | Oil & Gas Operator | Apr 2024 |
| 434 | Premier Natural Resources, L.P. | Tulsa, OK 74105 | Oil & Gas Operator | Feb 2007 |
| 435 | Premier Natural Resources, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2024 |
| 436 | Prevail Energy, Inc | Corpus Chrsti, TX 78469 | Oil & Gas Operator | Apr 2024 |
| 437 | Price Drilling & Exploration Co. | Benavides, TX 78341 | Oil & Gas Operator | Jul 2013 |
| 438 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2024 |
| 439 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | Apr 2024 |
| 440 | Proex Energy Management, L.L.C. | Spring, TX 77386 | Oil & Gas Operator | Apr 2024 |
| 441 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | Apr 2024 |
| 442 | Proton Energy, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2005 |
| 443 | Pursuit Oil & Gas STX, LLC | Houston, TX 77024 | Oil & Gas Operator | Apr 2024 |
| 444 | Pursuit Oil & Gas, LLC | Houston, TX 77024 | Gas Operator | Sep 2019 |
| 445 | PXP Gulf Coast Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 446 | Quest Research & Dev. Corp. | Weatherford, TX 76086 | Oil & Gas Operator | Apr 2024 |
| 447 | R. K. G. Engineering, Inc. | Odessa, TX 79760 | Oil & Gas Operator | Apr 2024 |
| 448 | R.C.I. Energy | Alice, TX 78333 | Oil & Gas Operator | Apr 2024 |
| 449 | Radius Operating, LLC | Round Rock, TX 78664 | Oil & Gas Operator | Apr 2024 |
| 450 | Raker Resources LLC | Houston, TX 77042 | Oil & Gas Operator | Apr 2024 |
| 451 | Ramtex Energy LLC | Tulsa, OK 74152 | Oil & Gas Operator | Apr 2024 |
| 452 | Red Water Resources, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | Apr 2024 |
| 453 | Reddy Disposals, LLC | Beeville, TX 78104 | Oil Operator | Apr 2024 |
| 454 | Redwood Operating, Inc. | Houston, TX 77058 | Oil & Gas Operator | Apr 2024 |
| 455 | Reef Exploration, L.P. | Richardson, TX 75080 | Oil & Gas Operator | Apr 2024 |
| 456 | Rego Development Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2002 |
| 457 | Reh Energy, Inc. | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Apr 2024 |
| 458 | Reichmann Petroleum Corp. | Grapevine, TX 76051 | Oil & Gas Operator | Apr 2024 |
| 459 | Remora Operating, LLC | Houston, TX 77056 | Oil & Gas Operator | Apr 2024 |
| 460 | Reo Operating LLC | Austin, TX 78747 | Oil & Gas Operator | Apr 2024 |
| 461 | Resource Management Company | Fredericksbrg, TX 78624 | Oil & Gas Operator | Feb 2015 |
| 462 | Richman Petroleum Corp. | Grapevine, TX 76051 | Oil & Gas Operator | Jul 2006 |
| 463 | Ricochet Energy, Inc. | San Antonio, TX 78258 | Oil & Gas Operator | Apr 2024 |
| 464 | Riddle Engineering Corp. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2011 |
| 465 | Rim Operating, Inc. | Englewood, CO 80112 | Oil & Gas Operator | Apr 2024 |
| 466 | Rincon Petroleum Corporation | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2024 |
| 467 | Rio Grand Exploration, LLC | San Antonio, TX 78216 | Oil & Gas Operator | Apr 2024 |
| 468 | Rio Grande E&P II, LLC | Houston, TX 77092 | Gas Operator | Apr 2024 |
| 469 | Rio Grande E&P, LLC | Houston, TX 77024 | Gas Operator | May 2022 |
| 470 | Ritter Properties, LTD. | Fredericksbrg, TX 78624 | Oil & Gas Operator | Apr 2024 |
| 471 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 472 | Robertson Resources, Inc. | Midland, TX 79708 | Oil & Gas Operator | Apr 2024 |
| 473 | Rockdale Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Dec 2020 |
| 474 | Rockford Energy Partners II, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2007 |
| 475 | Rollert Co., Inc., The | Luling, TX 78648 | Oil & Gas Operator | Nov 2000 |
| 476 | Ronde Operating, LLC | Houston, TX 77006 | Oil & Gas Operator | Mar 2021 |
| 477 | Rosetta Resources Operating LP | San Antonio, TX 78216 | Oil & Gas Operator | Apr 2024 |
| 478 | Rosewood Resources, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2024 |
| 479 | Rowden Oil & Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jun 2023 |
| 480 | Royal Oil & Gas Corp. | Indiana, PA 15701 | Oil & Gas Operator | Apr 2014 |
| 481 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2024 |
| 482 | RWJ Operating LLC | Dallas, TX 75201 | Oil & Gas Operator | Apr 2024 |
| 483 | Rystin Oil & Gas | Sugar Land, TX 77487 | Oil & Gas Operator | Apr 2024 |
| 484 | S & V Operating | Zephyr, TX 76890 | Oil & Gas Operator | Apr 2024 |
| 485 | Sabco Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2011 |
| 486 | Sabco Operating Company, LLC | Houston, TX 77056 | Oil & Gas Operator | Jun 2018 |
| 487 | Safari Production Company, Inc. | McAllen, TX 78501 | Oil & Gas Operator | Apr 2024 |
| 488 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 489 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 490 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 491 | Samson Lone Star, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2024 |
| 492 | San Antonio Gas & Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2000 |
| 493 | San Isidro Development Co, L. C. | Sandia, TX 78383 | Oil & Gas Operator | Apr 2024 |
| 494 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Apr 2024 |
| 495 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 496 | Sandalwood Exploration, L.P. | Houston, TX 77056 | Oil & Gas Operator | Apr 2024 |
| 497 | Sandalwood Oil & Gas, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2024 |
| 498 | Sandel Operating Company | Huntsville, TX 77340 | Oil & Gas Operator | Apr 2024 |
| 499 | Santa Fe Energy Oper. Part., LP | Houston, TX 77057 | Oil & Gas Operator | Dec 1994 |
| 500 | Santos USA Corp. | Houston, TX 77042 | Oil & Gas Operator | Dec 2008 |