| 4301 | Northwest Exploration Co | Salt Lake City, UT 84108-0900 | Oil & Gas Operator | Sep 1991 |
| 4302 | Northwest Oil Company | Dallas, TX 75204 | Oil & Gas Operator | Jun 2014 |
| 4303 | Northwind Development Company | | Oil Operator | Oct 1995 |
| 4304 | Northwind Oil Company | Tulsa, OK 74137 | Oil & Gas Operator | May 1998 |
| 4305 | Nossaman E Oil Inc | Del City, OK 73155-5449 | Oil Operator | Oct 2002 |
| 4306 | Notting Hill Energy LLC | Fort Worth, TX 76101 | Oil & Gas Operator | Mar 2025 |
| 4307 | Nova Energy Corporation | Denver, CO 80201 | Oil & Gas Operator | Jun 2003 |
| 4308 | Novy Oil & Gas, Inc. | Goddard, KS 67052 | Oil & Gas Operator | Jan 2025 |
| 4309 | Nowata Gas Company | Tulsa, OK 74136 | Oil & Gas Operator | Sep 1997 |
| 4310 | Nowata Petroleum Operating Co | Nowata, OK 74048-9617 | Oil Operator | Aug 2014 |
| 4311 | NRG Oil LLC | Stratford, OK 74872-9732 | Oil Operator | Feb 2012 |
| 4312 | NTR Energy LLC | Caney, KS 67333 | Oil & Gas Operator | Apr 2020 |
| 4313 | Nub'S Well Servicing Inc | Ratliff City, OK 73481 | Oil & Gas Operator | Jan 2025 |
| 4314 | Nutt Jerrie | Duncan, OK 73534-0698 | Oil & Gas Operator | Nov 2016 |
| 4315 | NWM Operating Inc | Okeene, OK 73763 | Oil & Gas Operator | Jan 2025 |
| 4316 | NWM Properties LLC | Tulsa, OK 74131-4426 | Oil Operator | Dec 2024 |
| 4317 | Nyc Resources LTD | Tulsa, OK 74133-5700 | Oil & Gas Operator | Sep 2014 |
| 4318 | Nye Oil Company | Oklahoma City, OK 73118-1245 | Oil & Gas Operator | Jun 2004 |
| 4319 | Nytex Energy LLC | Edmond, OK 73083-5946 | Oil & Gas Operator | Sep 2015 |
| 4320 | Nytex, L.L.C. | Edmond, OK 73083 | Oil & Gas Operator | Feb 2006 |
| 4321 | O G & E | Oklahoma City, OK 73124 | Oil & Gas Operator | Feb 2014 |
| 4322 | O K Swabbing Inc | Hennessey, OK 73742 | Oil & Gas Operator | Dec 2024 |
| 4323 | O'Blue Corp. | Kerrville, TX 78028 | Oil & Gas Operator | Mar 1998 |
| 4324 | O'Brien Energy Resources Corp | Portsmouth, NH 03801 | Oil & Gas Operator | Mar 2025 |
| 4325 | O'Brien Oil Corporation | Guthrie, OK 73044-3154 | Oil & Gas Operator | Dec 2024 |
| 4326 | O'Brien Oil LLC | Guthrie, OK 73044-3154 | Oil & Gas Operator | Apr 2020 |
| 4327 | O'Brien Resources LLC | Shreveport, LA 71136 | Oil Operator | Nov 2017 |
| 4328 | O'Donnell Bill C | Tulsa, OK 74135-4241 | Oil & Gas Operator | Oct 2014 |
| 4329 | O'Hern Morris D | Mounds, OK 74047-5163 | Oil & Gas Operator | Sep 2016 |
| 4330 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | Jan 2025 |
| 4331 | O'Neal Oil Company | Nocona, TX 76255 | Oil & Gas Operator | Mar 2025 |
| 4332 | O'Neal, Lindell | Nocona, TX 76255 | Oil & Gas Operator | Dec 2024 |
| 4333 | O'Neill Properties, LTD. | Midland, TX 79702 | Oil & Gas Operator | Mar 2025 |
| 4334 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2025 |
| 4335 | Oak Hill Petroleum Corporation | Oklahoma City, OK 73116-5627 | Oil & Gas Operator | Dec 2024 |
| 4336 | Oak Hills Drilling & Oper., LLC | Holdenville, OK 74848 | Oil & Gas Operator | May 2013 |
| 4337 | Oak Hills Energy Inc | Holdenville, OK 74848-0470 | Oil & Gas Operator | Sep 2014 |
| 4338 | Oak Resources Inc | Tulsa, OK 74153 | Oil & Gas Operator | Aug 2013 |
| 4339 | Oak Tree Natural Res LLC | Oklahoma City, OK 73120-5065 | Oil & Gas Operator | Mar 2015 |
| 4340 | Oak Valley SWD LLC | Enid, OK 73703-4637 | Oil Operator | Aug 2022 |
| 4341 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 4342 | Oakwood Resources, Inc. | Dallas, TX 75374 | Oil & Gas Operator | May 1998 |
| 4343 | Oasis Energy Resources LLC | Norman, OK 73072-9668 | Oil & Gas Operator | Dec 2024 |
| 4344 | Obele Oil Corporation | Sedona, AZ 86336-5745 | Oil & Gas Operator | May 2017 |
| 4345 | Obele Operating Company LLC | Sedona, AZ 86336-5745 | Oil & Gas Operator | Nov 2024 |
| 4346 | Oberlander Leslie A Jake | Covington, OK 73730 | Oil Operator | Jun 2007 |
| 4347 | Occidental Energy MKT Inc | Houston, TX 77001 | Oil & Gas Operator | Jan 2011 |
| 4348 | Ochiltree Oil Company | Edmond, OK 73034 | Oil & Gas Operator | Apr 2020 |
| 4349 | Octagon Resources LLC | Norman, OK 73071-1295 | Oil & Gas Operator | May 2015 |
| 4350 | Odell Larry | Oologah, OK 74053 | Oil Operator | Apr 2011 |
| 4351 | Odessa Oil Investment Co., Inc. | Odessa, TX 79762 | Oil & Gas Operator | Nov 2016 |
| 4352 | Odum Ronald L | Garfield, AR 72732 | Oil Operator | Dec 2024 |
| 4353 | Oex-1 LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Mar 2024 |
| 4354 | Oexco, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 4355 | Offield Lease Operations LLC | Wilson, OK 73463 | Oil & Gas Operator | May 2023 |
| 4356 | Ofs-Tulsa Corporation | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 1997 |
| 4357 | Oil & Gas Exploration Inc | Cleveland, OK 74020 | Oil & Gas Operator | Aug 2013 |
| 4358 | Oil & Gas Unlimited Inc | | Oil & Gas Operator | May 2013 |
| 4359 | Oil Center Operating Inc | Fort Worth, TX 76102-5108 | Oil & Gas Operator | Apr 2014 |
| 4360 | Oil Creek Production Company | Prague, OK 74864-0667 | Oil & Gas Operator | Jul 2024 |
| 4361 | Oil Exploration Of America Inc | Sisseton, SD 57262-9503 | Oil & Gas Operator | Jun 2001 |
| 4362 | Oil Investors Inc | Crescent, OK 73028 | Oil & Gas Operator | Jan 2025 |
| 4363 | Oil Lift, Incorporated | Metairie, LA 70002 | Oil & Gas Operator | Apr 2020 |
| 4364 | Oil Operations Inc | | Oil & Gas Operator | Apr 2011 |
| 4365 | Oil Patch Energy LLC | Tulsa, OK 74017 | Oil & Gas Operator | Dec 2024 |
| 4366 | Oil Pool Inc | Tulsa, OK 74132-2659 | Oil & Gas Operator | Dec 2024 |
| 4367 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Mar 2025 |
| 4368 | Oil Production Management Inc | Squaw Valley, CA 93675-9725 | Oil & Gas Operator | Dec 2002 |
| 4369 | Oil Production Systems Inc | Cushing, OK 74023 | Oil & Gas Operator | Jan 2013 |
| 4370 | Oil Property Management, Inc. | Attica, KS 67009 | Oil & Gas Operator | Feb 2021 |
| 4371 | Oil Recovery Systems Inc | Tulsa, OK 74145-4619 | Oil & Gas Operator | Dec 2024 |
| 4372 | Oil State Petroleum Inc | Jennings, OK 74038 | Oil & Gas Operator | Dec 2024 |
| 4373 | Oil Ventures LTD | | Oil & Gas Operator | Jan 2013 |
| 4374 | Oilbank Production LLC | Norman, OK 73072 | Oil Operator | Dec 2024 |
| 4375 | Oilco Energy Inc | Duncan, OK 73533 | Oil & Gas Operator | Mar 2015 |
| 4376 | Oilco Gas Co LC | Duncan, OK 73534 | Oil & Gas Operator | Dec 2014 |
| 4377 | Oilfield Leasing Inc | Cushing, OK 74023-0967 | Oil & Gas Operator | Aug 2018 |
| 4378 | Oilfield Operating Company | Cushing, OK 74023-1347 | Oil & Gas Operator | Jan 2018 |
| 4379 | Oilrox Resources LLC | San Antonio, TX 78258 | Oil & Gas Operator | Jan 2025 |
| 4380 | Oilsearch Corporation | Albuquerque, NM 87109 | Oil & Gas Operator | Feb 1994 |
| 4381 | Oilton Petroleum Inc | Oilton, OK 74052-0459 | Oil & Gas Operator | Oct 2001 |
| 4382 | Oilwell Operators, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Mar 2025 |
| 4383 | Ok Production Services Inc | Broken Arrow, OK 74014 | Oil & Gas Operator | Dec 2024 |
| 4384 | Okc Energy Corporation | Oklahoma City, OK 73120-3119 | Oil & Gas Operator | Nov 2014 |
| 4385 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2024 |
| 4386 | Okie Oil Inc | Sapulpa, OK 74067-0290 | Oil & Gas Operator | Mar 2011 |
| 4387 | Okla Petroleum Energies Corp | | Oil Operator | Jan 2013 |
| 4388 | Okla Petroleum Reclaimers Inc | Kellyville, OK 74039 | Oil Operator | Jul 2020 |
| 4389 | Okla Sub-Surface Pump & Supply Co | Seminole, OK 74804 | Oil & Gas Operator | Sep 2024 |
| 4390 | Oklahoma & Northwestern Co. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 1997 |
| 4391 | Oklahoma Basic Economy Corp | Houston, TX 77002-6003 | Oil & Gas Operator | Apr 2020 |
| 4392 | Oklahoma Cellulose Inc | Cleveland, OK 74020 | Oil Operator | Dec 2024 |
| 4393 | Oklahoma Crude Inc | Broken Arrow, OK 74012 | Oil & Gas Operator | Apr 2024 |
| 4394 | Oklahoma Crude Reclaimers, LLC | | Oil Operator | Jan 2025 |
| 4395 | Oklahoma Energy Acquisitions LP | Houston, TX 77094-1900 | Oil & Gas Operator | Dec 2024 |
| 4396 | Oklahoma Energy Development Co | | Oil & Gas Operator | Sep 2008 |
| 4397 | Oklahoma Energy Exchange LLC | Duncan, OK 73534-1105 | Oil & Gas Operator | Sep 2012 |
| 4398 | Oklahoma Energy LLC | Skiatook, OK 74070-3998 | Oil Operator | Nov 2024 |
| 4399 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 4400 | Oklahoma Gas & Oil Corporation | Okemah, OK 74859 | Oil Operator | Oct 2018 |