| O'Connor, L.W. O-2-7979 | Mary Ellen Oconnor (FT-8) | Refugio | 1 | 43.8K | 52.7K | Oct 1996 – Dec 2015 | O'Connor Energy Management, LLC |
| O'Connor, L. W. O-2-7250 | Mary Ellen Oconnor (FS-75) | Refugio | 5 | 39.8K | 54K | Oct 1996 – Dec 2015 | O'Connor Energy Management, LLC |
| O'Connor, L. W. O-2-958 | Mary Ellen Oconnor (FQ-40 Sand) | Refugio | 7 | 30K | 145K | May 2006 – Dec 2015 | O'Connor Energy Management, LLC |
| O'Connor, L. W. 2 O-2-9036 | Mary Ellen O'Connor (5500 Sand) | Refugio | 1 | 20.9K | 2.17K | Oct 2006 – Dec 2015 | O'Connor Energy Management, LLC |
| O'Connor, Mary Ellen O-2-7933 | Mary Ellen Oconnor (FS-75) | Refugio | 16 | 181K | 481K | Apr 1994 – Nov 2015 | O'Connor Energy Management, LLC |
| L.W. O'Connor 2 O-2-9043 | Mary Ellen Oconnor (Stray 5400) | Refugio | 1 | 20.1K | 51.4K | Oct 2006 – May 2015 | O'Connor Energy Management, LLC |
| Obrien, J. J. O-2-1409 | Refugio Old | Refugio | 4 | 46.2K | 133K | Feb 1997 – Jan 2006 | Eagleford Operating, Inc. |
| O'Brien, J. J. O-2-8664 | Refugio Old (5500) | Refugio | 2 | 8.91K | 2.68K | Apr 2001 – May 2004 | off the schedule |
| O'Connor, Mary Ellen O-2-8485 | Mary Ellen Oconnor (FT-18 Sand) | Refugio | 1 | 12.7K | 31.8K | Apr 1996 – May 2003 | this operator |
| O'Connor, Thomas James O-2-8142 | Mary Ellen Oconnor (FS-96) | Bee | 2 | 100 | 25 | Feb 1996 – Feb 1998 | off the schedule |
| Finley, Dee O-2-7640 | Palmetto Bend, W. (a-8 Frio) | Jackson | 1 | 27 | 11 | Oct 1995 – Aug 1996 | Pitchfork Oil & Gas, Inc. |
| O'Connor, Mary Ellen O-2-8106 | Mary Ellen Oconnor (FQ-40 Sand) | Refugio | 2 | 1.23K | 6.7K | Sep 1995 – Mar 1996 | off the schedule |
| O'Connor, Mary Ellen O-2-8071 | Mary Ellen Oconnor (D-1) | Refugio | 1 | 0 | 0 | no volume · 379 mo | this operator |
| O'Connor, L.W. O-2-7996 | Mary Ellen Oconnor (FT-28) | Refugio | 1 | 0 | 0 | no volume · 233 mo | O'Connor Energy Management, LLC |
| O'Brien, J. J. O-2-8752 | Refugio Old | — | 0 | 0 | 0 | no volume · 1 mo | off the schedule |
| Ryals, Pearson, Estate O-2-2663 | Refugio Old | Refugio | 1 | 0 | 0 | no volume · 130 mo | Eagleford Operating, Inc. |
| Powers, Phil O-2-1406 | Refugio Old | Refugio | 6 | 0 | 0 | no volume · 130 mo | Eagleford Operating, Inc. |