| 3201 | Northern Natural Gas Prod | | Gas Operator | Oct 1989 |
| 3202 | Northern Pump Company | Denver, CO 80202-3130 | Oil & Gas Operator | Feb 2006 |
| 3203 | Northstar Investments, Inc. | Wichita, KS 67230 | Oil & Gas Operator | Sep 2025 |
| 3204 | Northwest Well Service, Inc. | Merino, CO 80741 | Oil Operator | Mar 2002 |
| 3205 | Norwood Oil | Greeley, CO 80634 | Oil Operator | Mar 1996 |
| 3206 | Nott, Gregory | Wichita, KS 67214 | Oil Operator | Sep 2025 |
| 3207 | Novy Oil & Gas, Inc. | Goddard, KS 67052 | Oil & Gas Operator | Dec 2025 |
| 3208 | Noxxe | Ottawa, KS 66067 | Oil & Gas Operator | Dec 2023 |
| 3209 | NPF Energy Corporation | Boise, ID 83708 | Oil & Gas Operator | Sep 2025 |
| 3210 | NRD - Rein Resources, A General Partnership | Union, KY 41091 | Oil Operator | Sep 2025 |
| 3211 | Numac LLC | Cherryvale, KS 67335 | Oil Operator | Jun 2025 |
| 3212 | Nuss Oil Operations | | Oil & Gas Operator | Aug 1998 |
| 3213 | Nuss Sally | | Oil Operator | Mar 1982 |
| 3214 | Nuss, Fred J. | Hoisington, KS 67544 | Gas Operator | Sep 2025 |
| 3215 | Nuss, Kenneth J. | Russell, KS 67665 | Oil Operator | Aug 1997 |
| 3216 | O S & J Operatin | | Oil Operator | Nov 1984 |
| 3217 | O'Brien Energy Company | Shreveport, LA 71136 | Oil & Gas Operator | Sep 2019 |
| 3218 | O'Brien Energy Resources Corp | Portsmouth, NH 03801 | Oil & Gas Operator | Feb 2026 |
| 3219 | O'Brien Resources LLC | Shreveport, LA 71136 | Oil Operator | Nov 2017 |
| 3220 | O'Connell, James P. | Vacaville, CA 95687 | Oil Operator | Nov 2009 |
| 3221 | O'Hare Energy Co | | Oil Operator | Dec 1983 |
| 3222 | O-K Gas SVCS | | Gas Operator | Jun 2020 |
| 3223 | Oak Ridge LLC | Wellsville, KS 66092 | Oil Operator | Dec 2019 |
| 3224 | Oaks Petroleum I | | Oil Operator | Jul 1987 |
| 3225 | Oakwood Resources Inc | Dallas, TX 75374 | Oil & Gas Operator | May 1998 |
| 3226 | Oasis Petroleum | | Gas Operator | Feb 1984 |
| 3227 | Oast, Thomas H. | Greenville, NC 27835 | Oil Operator | Nov 1985 |
| 3228 | Occidental Energy Marketing, Inc. | Houston, TX 77227 | Gas Operator | Sep 2015 |
| 3229 | Ocean Energy Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 3230 | Ocfiw Oil Company, Inc. | Hartington, NE 68739 | Oil & Gas Operator | Dec 2009 |
| 3231 | Odyssey Petroleum, Inc. | Overland Park, KS 66282 | Oil & Gas Operator | Apr 2009 |
| 3232 | Ogh Oil Company | | Oil Operator | Sep 1995 |
| 3233 | Ohio Kentucky Oil Corporation | Lexington, KY 40503 | Oil & Gas Operator | Dec 2023 |
| 3234 | Oil & Gas Producers, Inc | Topeka, KS 66604 | Oil Operator | Jun 2004 |
| 3235 | Oil & Gas Servic | | Oil Operator | Jun 1983 |
| 3236 | Oil And Gas Management, Inc. | Kansas City, MO 64106 | Oil Operator | Apr 2011 |
| 3237 | Oil Capital Corporation | Littleton, CO 80122 | Gas Operator | May 2009 |
| 3238 | Oil Company Of America, Inc. | Hays, KS 67601 | Oil Operator | Dec 2009 |
| 3239 | Oil Drillers & D | | Oil & Gas Operator | Feb 1992 |
| 3240 | Oil Equipment As | | Gas Operator | Jun 1989 |
| 3241 | Oil Field Manage | | Oil Operator | Jun 1991 |
| 3242 | Oil Internationa | | Oil Operator | Jun 1986 |
| 3243 | Oil Lift Inc | Metairie, LA 70002 | Oil & Gas Operator | Apr 2020 |
| 3244 | Oil Partners | Salina, KS 67401 | Oil Operator | Jun 2001 |
| 3245 | Oil Partners, LLC | Salina, KS 67401 | Oil Operator | Sep 2025 |
| 3246 | Oil Producers In | | Oil & Gas Operator | Dec 1996 |
| 3247 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Feb 2026 |
| 3248 | Oil Production S | | Oil Operator | Sep 1993 |
| 3249 | Oil Prop Company | | Oil & Gas Operator | Sep 1995 |
| 3250 | Oil Prop Investm | | Oil Operator | Dec 1995 |
| 3251 | Oil Properties Co., Inc. | Wichita, KS 67208 | Gas Operator | Dec 2009 |
| 3252 | Oil Property Man | | Oil & Gas Operator | Jun 1995 |
| 3253 | Oil Property Management Inc | Attica, KS 67009 | Oil & Gas Operator | Feb 2021 |
| 3254 | Oil Tech Producers Corporation | Moundridge, KS 67107 | Gas Operator | Sep 2025 |
| 3255 | Oil-Tech Prod Co | | Oil & Gas Operator | Oct 1992 |
| 3256 | Oilfield Search | | Oil Operator | Mar 1990 |
| 3257 | Oilfield Services, LLC | Winfield, KS 67156 | Oil Operator | Nov 2017 |
| 3258 | Oilfield Truck Service | | Oil Operator | Jun 2014 |
| 3259 | Oilwell Operator | | Gas Operator | Dec 1994 |
| 3260 | Oklahoma Energy & Exploration, Inc. | Tulsa, OK 74114 | Oil Operator | Jan 1996 |
| 3261 | Oklahoma Rig & Salvage Inc | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2015 |
| 3262 | Okmar Oil Compan | | Oil & Gas Operator | Feb 1995 |
| 3263 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 3264 | Okt Resources, LLC | Edmond, OK 73013 | Oil & Gas Operator | Feb 2026 |
| 3265 | Ol' Oily LLC | | Oil Operator | Sep 2025 |
| 3266 | Oleum Incorporat | | Gas Operator | Dec 1990 |
| 3267 | Olson D Producti | | Oil Operator | Jul 1994 |
| 3268 | Olson-Anderson Lease | | Oil Operator | Mar 2018 |
| 3269 | Olympic Oil, Inc. | Hutchinson, KS 67502 | Oil & Gas Operator | Jul 2025 |
| 3270 | Olympic Petroleu | | Oil & Gas Operator | Jul 1993 |
| 3271 | Omega Enterprise | | Oil Operator | Sep 1990 |
| 3272 | One Source Financial Services Inc. | McAllen, TX 78501 | Gas Operator | Dec 2019 |
| 3273 | Oneok Bushton Proces | | Gas Operator | Mar 2007 |
| 3274 | Oneok Energy Service | | Gas Operator | Dec 2008 |
| 3275 | Oneok Exploratio | | Oil & Gas Operator | Mar 1995 |
| 3276 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 3277 | Oneok Gas Processing LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 3278 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 3279 | Onnen, Gerhard E. | Yates Center, KS 66783 | Oil Operator | Feb 2002 |
| 3280 | Onshore, L.L.C. | Wichita, KS 67205 | Oil & Gas Operator | Dec 2009 |
| 3281 | Onyxx Oil Corpor | | Oil Operator | Jul 1992 |
| 3282 | Oolite Energy Corp | Amarillo, TX 79105 | Oil & Gas Operator | Apr 2022 |
| 3283 | Opco LLC | Chase, KS 67524 | Oil Operator | Dec 2019 |
| 3284 | Opdycke Lease Partners, A General Partnership | Russell, KS 67665 | Oil Operator | Sep 2025 |
| 3285 | Opef Partnership, A General Partnership | Overland Park, KS 66221 | Oil Operator | Dec 2011 |
| 3286 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Dec 2025 |
| 3287 | Oryx Energy Comp | | Oil & Gas Operator | Apr 1991 |
| 3288 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 3289 | Osage Energy, LLC | Colony, KS 66015 | Oil Operator | Aug 2025 |
| 3290 | Osage Resources, LLC | Wichita, KS 67202 | Oil & Gas Operator | May 2025 |
| 3291 | Osborn Energy, LLC | Bucyrus, KS 66013 | Oil & Gas Operator | Jul 2017 |
| 3292 | Osborn Heirs Com | | Oil & Gas Operator | May 1995 |
| 3293 | Osborn Heirs Company LTD | San Antonio, TX 78217 | Oil & Gas Operator | Sep 2025 |
| 3294 | Osborn Oil & Gas | | Oil & Gas Operator | Jun 1991 |
| 3295 | Osci Oil And Gas, Inc. | Parker, KS 66072 | Oil Operator | Jun 1998 |
| 3296 | Oswego Oil & Gas | | Oil & Gas Operator | Jun 1984 |
| 3297 | Outback Oil, Inc. | Pratt, KS 67124 | Gas Operator | Sep 2019 |
| 3298 | Outlaw Well Service LLC | Hays, KS 67601 | Oil Operator | Jun 2025 |
| 3299 | Overland Exploration Company | | Oil Operator | Aug 2025 |
| 3300 | Owen'S Pumping Service | | Oil Operator | Sep 2025 |