| 301 | Research Exploration, LLC | Kingwood, TX 77339 | Oil & Gas Operator | Feb 2018 |
| 302 | Reserve Acquisition Group | Tulsa, OK 74153 | Oil & Gas Operator | Dec 1993 |
| 303 | Reserve Management, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jul 2026 |
| 304 | Reserve Operating Corp. | Houston, TX 77040 | Oil & Gas Operator | Jul 2026 |
| 305 | Reserve Production, Inc. | Tyler, TX 75713 | Oil & Gas Operator | Mar 2008 |
| 306 | Residual Flow Operating, LLC | | Oil Operator | Jul 2026 |
| 307 | Resolute Natural Res. Co., LLC | Midland, TX 79706 | Oil & Gas Operator | Jul 2026 |
| 308 | Resolute Natural Resources Co., LLC | Denver, CO 80203 | Oil & Gas Operator | Feb 2017 |
| 309 | Resource Expl & Prod, Inc. | Salado, TX 76571 | Oil & Gas Operator | Jul 2026 |
| 310 | Resource Management Company | Fredericksbrg, TX 78624 | Oil & Gas Operator | Feb 2015 |
| 311 | Resource Oil And Gas, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Jul 2026 |
| 312 | Resource Operating Company | Abilene, TX 79601 | Oil & Gas Operator | Jul 1997 |
| 313 | Ress Production Co. | Farmington, NM 87499 | Oil & Gas Operator | Mar 2026 |
| 314 | Restoration Energy LLC | Amarillo, TX 79124 | Oil & Gas Operator | Jul 2026 |
| 315 | Restore Operating LLC | Andrews, TX 79714 | Oil & Gas Operator | Jul 2026 |
| 316 | Retama Oil Corporation | Uvalde, TX 78801 | Oil & Gas Operator | Jul 2026 |
| 317 | Retamco Operating Inc | Red Lodge, MT 59068 | Oil & Gas Operator | Jun 2026 |
| 318 | Retriever Operating LLC | Midland, TX 79704 | Oil & Gas Operator | Jul 2026 |
| 319 | Reunion Energy Company | Houston, TX 77056 | Oil & Gas Operator | May 1996 |
| 320 | Revard Petroleum, L.L.C. | Tulsa, OK 74170 | Oil & Gas Operator | Jul 2026 |
| 321 | Reveille Resources | Houston, TX 77084 | Oil & Gas Operator | Apr 2011 |
| 322 | Reveille Resources (Texas), Inc. | Houston, TX 77084 | Oil & Gas Operator | Jan 2013 |
| 323 | Revelation Oil & Gas LLC | Dumas, TX 79029 | Oil & Gas Operator | Jul 2026 |
| 324 | Revenant Energy Operating LLC | Plano, TX 75024 | Gas Operator | Jul 2026 |
| 325 | Reverence Operating LLC | Odessa, TX 79768 | Oil & Gas Operator | Jul 2026 |
| 326 | Revier Resources Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2005 |
| 327 | Revier, J. B. Prod. Company | Wichita Falls, TX 76302 | Oil & Gas Operator | Apr 1996 |
| 328 | Revilo Exploration, Inc. | Richardson, TX 75081 | Oil & Gas Operator | Jul 2021 |
| 329 | Revolution Operating Company,LLC | Oklahoma City, OK 73134 | Oil & Gas Operator | Jul 2024 |
| 330 | Rex Energy Operating Corp. | State College, PA 16801 | Oil & Gas Operator | Jun 2012 |
| 331 | Rex Oil, A Texas Partnership | Hondo, TX 78861 | Oil & Gas Operator | May 2003 |
| 332 | Rexcom, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2026 |
| 333 | Reynolds Drilling Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jul 2026 |
| 334 | Reynolds E & P, Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jul 2026 |
| 335 | Reynolds, E. P., Jr. | Graham, TX 76450 | Oil & Gas Operator | Jul 2026 |
| 336 | Reynolds, J. C. & W. F. | Wichita Falls, TX 76301 | Oil & Gas Operator | Jul 2026 |
| 337 | Reynolds, Richard | Seymour, TX 76380 | Oil & Gas Operator | Mar 2008 |
| 338 | Rfe Operating, LLC | Tyler, TX 75703 | Oil & Gas Operator | Jul 2026 |
| 339 | RGX Energy LLC | Plano, TX 75025 | Oil & Gas Operator | Oct 2019 |
| 340 | RHB Exploration & Production,LLC | Grapevine, TX 76099 | Oil & Gas Operator | Jul 2026 |
| 341 | RHC Energy (USA) LLC | Houston, TX 77027 | Oil Operator | Jul 2026 |
| 342 | Rheaco Oil Company, LTD. | Sourlake, TX 77659 | Oil Operator | Jul 2026 |
| 343 | Rheata Resources, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2026 |
| 344 | Rhodes Disposal, Inc. | Bryson, TX 76427 | Oil Operator | Jul 2026 |
| 345 | Rhodes Drilling Company | Abilene, TX 79608 | Oil & Gas Operator | Sep 2000 |
| 346 | Rhombus Operating Co., LTD | Littleton, CO 80160 | Oil & Gas Operator | May 2026 |
| 347 | Rhonda Operating Company | Midland, TX 79710 | Oil & Gas Operator | Aug 2017 |
| 348 | RHR Oil & Gas, LLC | Fort Worth, TX 76107 | Oil Operator | Jul 2026 |
| 349 | Rhyne, J.V. | Cisco, TX 76437 | Oil & Gas Operator | Jul 2026 |
| 350 | Ria Mia Corporation | San Antonio, TX 78230 | Oil & Gas Operator | Apr 2011 |
| 351 | Rialto Oil & Gas Corporation | Houston, TX 77098 | Oil & Gas Operator | Oct 2012 |
| 352 | Riata Energy, Inc. | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2006 |
| 353 | Ric Petroleum, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Aug 2003 |
| 354 | Rice Drilling Company | Santa Anna, TX 76878 | Oil & Gas Operator | Jul 2026 |
| 355 | Rice, James D. | Santa Anna, TX 76878 | Oil & Gas Operator | Sep 2007 |
| 356 | Richard C. Bellows Family Trust | George West, TX 78022 | Oil Operator | Jul 2026 |
| 357 | Richard'S Texas Tea | Rockdale, TX 76567 | Oil Operator | Jul 2026 |
| 358 | Richards, Michael Dewain | Graham, TX 76450 | Oil & Gas Operator | Apr 2011 |
| 359 | Richards, Tot Dozer, Inc. | Throckmorton, TX 76483 | Oil & Gas Operator | May 2013 |
| 360 | Richards, Tot Oil Co. | Abilene, TX 79601 | Oil & Gas Operator | Jul 2026 |
| 361 | Richardson Oil Company | San Antonio, TX 78216 | Oil & Gas Operator | Aug 2003 |
| 362 | Richardson Operating Company | Denver, CO 80237 | Oil & Gas Operator | Apr 2026 |
| 363 | Richardson Resources Inc | Brownwood, TX 76801 | Oil & Gas Operator | Jul 2026 |
| 364 | Richardson, Bud II | Graham, TX 76450 | Oil & Gas Operator | Jul 2026 |
| 365 | Richardson, Marshall T. | Midfield, TX 77458 | Oil & Gas Operator | Jul 2026 |
| 366 | Richey Operating, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jul 2026 |
| 367 | Richey Properties, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jul 2026 |
| 368 | Richey, Ray Management Co., Inc. | Fort Worth, TX 76108 | Oil & Gas Operator | Jul 2026 |
| 369 | Richland Energy, Inc. | Irving, TX 75063 | Oil & Gas Operator | Jul 2026 |
| 370 | Richland Resources Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Jul 2026 |
| 371 | Richman Petroleum Corp. | Grapevine, TX 76051 | Oil & Gas Operator | Jul 2006 |
| 372 | Richmond Drilling Company | Midland, TX 79705 | Oil & Gas Operator | Apr 2017 |
| 373 | Richmond Operating Company | Midland, TX 79707 | Oil & Gas Operator | Feb 2007 |
| 374 | Richmond Petroleum Inc. | Amarillo, TX 79105 | Oil & Gas Operator | Aug 2003 |
| 375 | Richter Operating Company | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2007 |
| 376 | Rickaway Energy, Corp. | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2026 |
| 377 | Ricks Expl Acquisition Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2004 |
| 378 | Ricks Expl Acquisition LLC | Midland, TX 79701 | Oil & Gas Operator | Aug 2013 |
| 379 | Ricks Exploration, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2008 |
| 380 | Rico Oil Company | Graham, TX 76450 | Oil & Gas Operator | Jul 2026 |
| 381 | Ricochet Energy, Inc. | San Antonio, TX 78258 | Oil & Gas Operator | Jul 2026 |
| 382 | Ricon Petroleum Company | Shamrock, TX 79079 | Oil & Gas Operator | Mar 2008 |
| 383 | Riddle Engineering Corp. | Corpus Christ, TX 78401 | Oil & Gas Operator | Jul 2011 |
| 384 | Ridge Oil Company | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2026 |
| 385 | Ridge Petroleum Inc. | Tyler, TX 75701 | Oil & Gas Operator | Jul 2026 |
| 386 | Ridgeline Energy Inc. | Miami, FL 33130 | Oil & Gas Operator | Jul 2026 |
| 387 | Ridgeline Resources, LLC | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 388 | Ridgeway Exco, Inc. | San Antonio, TX 78279 | Oil & Gas Operator | Mar 1996 |
| 389 | Ridglea Energy I, LLC | Spring, TX 77379 | Oil & Gas Operator | Jul 2026 |
| 390 | Ridley Oil Corporation | Tyler, TX 75702 | Oil & Gas Operator | Nov 1996 |
| 391 | Rife Energy Operating, Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | Jul 2026 |
| 392 | Rife Oil Properties Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Jul 2026 |
| 393 | Rife Operating, LTD. | Fort Worth, TX 76107 | Oil & Gas Operator | Oct 2005 |
| 394 | Rife, M. O., Jr. | Fort Worth, TX 76107 | Oil & Gas Operator | Dec 1998 |
| 395 | Rig Petroleum, LLC | Spearman, TX 79081 | Oil & Gas Operator | Jul 2026 |
| 396 | Rig Runner Express Inc Of Texas | Kilgore, TX 75663 | Oil & Gas Operator | May 2014 |
| 397 | Rig Runner Express, Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Mar 2008 |
| 398 | Rigged Up, LLC | Graham, TX 76450 | Oil Operator | Jul 2026 |
| 399 | Riggins Energy Inc. | Vernon, TX 76385 | Oil & Gas Operator | Jul 2004 |
| 400 | Riggs Petroleum Company | Graham, TX 76450 | Oil & Gas Operator | Jul 2026 |