| Mellon Oil Unit O-2-2192 | T-C Oil Company, LLC only | Tom Oconnor (4400) | Refugio | 28 | 852K | 451K | by Jan 1993 – Mar 2015 |
| O'Connor, Mary Ellen O-2-7933 | O'Connor Energy Management, LLC only | Mary Ellen Oconnor (FS-75) | Refugio | 16 | 192K | 500K | Oct 1993 – Nov 2015 |
| O'Conner, Mary Ellen O-2-6698 | Dolphin Petroleum, LP only | Mary Ellen Oconnor (FQ-30) | Refugio | 3 | 174K | 391K | by Jan 1993 – Jul 2016 |
| Meoc-Mellon-State Unit O-2-11756 | T-C Oil Company, LLC only | Mary Ellen Oconnor (8200) | Refugio | 1 | 118K | 363K | Jun 2019 – Aug 2026 |
| O'Connor, L. W. O-2-7250 | O'Connor Energy Management, LLC only | Mary Ellen Oconnor (FS-75) | Refugio | 5 | 98K | 227K | by Jan 1993 – Dec 2015 |
| O'Conner, Mary Ellen O-2-5612 | Dolphin Petroleum, LP only | Mary Ellen Oconnor (D-1) | Refugio | 12 | 86.9K | 486K | by Jan 1993 – Jul 2016 |
| O Connor, Thos. -B- O-2-964 | Hilcorp Energy Company only | Mary Ellen Oconnor (FQ-40 Sand) | Refugio | 11 | 75.5K | 186K | by Jan 1993 – Mar 2018 |
| Meoc-Mellon-State Unit G-2-295806 | T-C Oil Company, LLC only | Mary Ellen O'Connor (8300) | Refugio | 1 | 65.2K | 169K | May 2023 – Aug 2026 |
| Oconnor, Mary Ellen O-2-5253 | Dolphin Petroleum, LP only | Mary Ellen Oconnor (Stray A) | Refugio | 6 | 57.1K | 261K | by Jan 1993 – Jul 2016 |
| O'Connor, L.W. O-2-7979 | O'Connor Energy Management, LLC only | Mary Ellen Oconnor (FT-8) | Refugio | 1 | 54.9K | 87.4K | Aug 1994 – Dec 2015 |
| O Connor, Thos. -B- O-2-954 | Hilcorp Energy Company only | Mary Ellen Oconnor (FQ- 9) | Refugio | 10 | 53.5K | 308K | by Jan 1993 – Jan 2016 |
| Welder-Terrell O-2-8831 | C & E Operating, Inc. only | Devils Run (Chamberlain 3A) | Refugio | 1 | 46.9K | 211K | Sep 2003 – Apr 2007 |
| O'Connor, L. W. O-2-958 | O'Connor Energy Management, LLC only | Mary Ellen Oconnor (FQ-40 Sand) | Refugio | 7 | 44.9K | 280K | by Jan 1993 – Dec 2015 |
| Oconnor, Mary Ellen O-2-5502 | Dolphin Petroleum, LP only | Woodsboro, South (4200) | Refugio | 9 | 44.4K | 123K | by Jan 1993 – Jul 2016 |
| Shelton, J. Isabella -C- O-2-1080 | High Plains Gas Systems, Inc. only | Mission River | Refugio | 1 | 40.1K | 10.4K | by Jan 1993 – Jun 2004 |
| Oconnor, Thos. -D- O-2-965 | Hilcorp Energy Company only | Mary Ellen Oconnor (FQ-40 Sand) | Refugio | 2 | 38.8K | 116K | by Jan 1993 – Aug 2013 |
| O'Conner, Mary Ellen O-2-5905 | Dolphin Petroleum, LP only | Mary Ellen Oconnor (FQ-25) | Refugio | 2 | 32.2K | 80K | by Jan 1993 – Jul 2016 |
| Oconnor, Mary Ellen O-2-5404 | Dolphin Petroleum, LP only | Mary Ellen Oconnor (5000) | Refugio | 2 | 31.6K | 99.2K | by Jan 1993 – Jul 2016 |
| Oconnor, Mary Ellen O-2-2708 | Dolphin Petroleum, LP only | Mary Ellen Oconnor (FS-96) | Refugio | 6 | 30.8K | 102K | by Jan 1993 – Jul 2016 |
| Thomas O'Connor 'B' O-2-10382 | Hilcorp Energy Company only | Mary Ellen Oconnor (Frio 6500) | Refugio | 3 | 28.4K | 67.2K | Oct 2012 – Mar 2018 |
| O'Connor, Thomas "B" O-2-7920 | Hilcorp Energy Company only | Mary Ellen Oconnor (Frio 6500) | Refugio | 1 | 27.7K | 89.3K | Nov 1993 – Mar 1997 |
| Oconnor, Thomas -B- O-2-957 | Hilcorp Energy Company only | Mary Ellen Oconnor (FQ-35 Sd.) | Refugio | 1 | 27.2K | 45.1K | by Jan 1993 – Feb 2010 |
| Meoc-Mellon-State Unit G-2-292773 | T-C Oil Company, LLC only | Mary Ellen OCONNOR(8100) | Refugio | 1 | 24.6K | 1.29M | Feb 2022 – Oct 2025 |
| Baumgartner -A- G-2-275006 | T-C Oil Company, LLC only | Dudley Campbell (Frio 6200) | Refugio | 1 | 23.9K | 91.5K | Sep 2014 – May 2017 |
| O'Connor, L. W. 2 O-2-9036 | O'Connor Energy Management, LLC only | Mary Ellen O'Connor (5500 Sand) | Refugio | 1 | 21.3K | 2.17K | Sep 2006 – Dec 2015 |
| L.W. O'Connor 2 O-2-9043 | O'Connor Energy Management, LLC only | Mary Ellen Oconnor (Stray 5400) | Refugio | 1 | 20.6K | 53.2K | Mar 2006 – May 2015 |
| Terrell Ranch "C" O-2-8188 | Wiser Oil Company, The only | Devil's Run (6600) | Refugio | 1 | 19.6K | 845 | Jul 1996 – May 1998 |
| Oconnor, Mary Ellen O-2-3126 | Dolphin Petroleum, LP only | Mary Ellen Oconnor (FQ- 9) | Refugio | 3 | 19.1K | 45.2K | by Jan 1993 – Jul 2016 |
| Welder-Terrell G-2-230170 | C & E Operating, Inc. only | Devils Run (Chamberlain 3A) | Refugio | 1 | 17.4K | 917K | May 2007 – Mar 2016 |
| O'Connor, Mary Ellen O-2-8485 | Emerald Oil & Gas LC only | Mary Ellen Oconnor (FT-18 Sand) | Refugio | 1 | 12.7K | 31.8K | Apr 1996 – May 2003 |
| O'Conner, Thomas -B- O-2-5757 | Hilcorp Energy Company only | Mary Ellen Oconnor (5000) | Refugio | 1 | 12.3K | 80.8K | by Jan 1993 – Jun 1998 |
| Meoc-Mellon-State Unit G-2-300938 | T-C Oil Company, LLC only | Mary Ellen O'Connor (7750) | Refugio | 1 | 11.9K | 285K | Nov 2025 – Aug 2026 |
| Mitchell, John N. O-2-3246 | High Plains Gas Systems, Inc. only | Mission River | Refugio | 1 | 11.6K | 10.5K | by Jan 1993 – Mar 2000 |
| O'Connor, Mary Ellen O-2-5592 | Dolphin Petroleum, LP only | Mary Ellen O'Connor (FS 97) | Refugio | 1 | 10.9K | 83.3K | by Jan 1993 – Aug 2014 |
| Welder-Terrell O-2-8839 | C & E Operating, Inc. only | Devil's Run (6600) | Refugio | 1 | 9.6K | 0 | Dec 2003 – Oct 2006 |
| Longoria Unit O-2-9272 | Bellows Operating Co., L. C. only | Refugio Heard (Area) | Refugio | 1 | 9.1K | 0 | Nov 2008 – Dec 2014 |
| O'Connor, Thomas "B" G-2-143511 | Quintana Pet. Corp. only | Mary Ellen O'Connor (8300) | Refugio | 1 | 8.42K | 108K | by Jan 1993 – Jul 1993 |
| El Oso Cattle Co. O-2-4185 | Citation Oil & Gas Corp. only | Mary Ellen Oconnor (FS-96) | Refugio | 2 | 8.33K | 16.7K | Jun 1993 – Mar 1999 |
| O'Connor, Thomas "B" O-2-7841 | Hilcorp Energy Company only | Mary Ellen O'Connor (FS-70) | Refugio | 2 | 8.32K | 74.3K | by Jan 1993 – May 1999 |
| Meoc-Mellon-State Unit G-2-297464 | T-C Oil Company, LLC only | Mary Ellen OCONNOR(8100) | Refugio | 1 | 7.53K | 439K | Jun 2024 – Aug 2026 |
| Shay, Mary A. O-2-5094 | Mueller Engineering Corp. only | Phil Power (5200-B) | Refugio | 1 | 7.53K | 39 | by Jan 1993 – Oct 1993 |
| O'Connor, Thomas "B" O-2-7897 | Quintana Pet. Corp. only | Mary Ellen O'Connor (8300) | Refugio | 1 | 7.24K | 135K | Aug 1993 – May 1995 |
| Oconnor, Mary Ellen O-2-5588 | Dolphin Petroleum, LP only | Mary Ellen Oconnor (8200) | Refugio | 1 | 6.16K | 79.7K | Jan 1994 – Jul 2016 |
| Welder-Terrell G-2-194134 | C & E Operating, Inc. only | Devil's Run (6600) | Refugio | 1 | 6.01K | 48.8K | Nov 2002 – Nov 2003 |
| O'Connor, Thomas "B" G-2-144285 | Quintana Pet. Corp. only | Mary Ellen Oconnor (Frio 6500) | Refugio | 1 | 5.6K | 175K | by Jan 1993 – Oct 1993 |
| El Oso Cattle Company O-2-5415 | Dolphin Petroleum, LP only | Mary Ellen Oconnor (Stray A) | Refugio | 1 | 4.75K | 34.9K | by Jan 1993 – Feb 2002 |
| M. E. O'Connor O-2-11735 | T-C Oil Company, LLC only | Mary Ellen Oconnor (Stray 5400) | Refugio | 1 | 4.66K | 16.6K | May 2019 – Dec 2019 |
| O'Connor, Thomas 'B' O-2-8387 | Hilcorp Energy Company only | Mary Ellen Oconnor (FT-5) | Refugio | 1 | 4.51K | 8.62K | Jul 1998 – Aug 2001 |
| Meoc-Mellon-State Unit O-2-12591 | T-C Oil Company, LLC only | Mary Ellen O'Connor (8300) | Refugio | 1 | 4.51K | 9.46K | Mar 2023 – Apr 2023 |
| Buckley, John O-2-2883 | Bellows Operating Co., L. C. only | Refugio Old | Refugio | 1 | 4K | 19 | by Jan 1993 – Jul 2009 |