| O'Brien, J. M. "E" G-2-231786 | Greta Operating Company LLC | Greta, W. (6300) | Refugio | 1 | 14.5K | 568K | Jun 2007 – Apr 2026 |
| Heard, J. F. B. G-2-218347 | Greta Operating Company LLC | Greta, North (6100) | Refugio | 1 | 14.4K | 317K | Dec 2005 – Oct 2014 |
| JM Obrien "A" G-2-214405 | Greta Operating Company LLC | Greta (6200, South) | Refugio | 1 | 5.78K | 229K | Jun 2005 – Aug 2012 |
| J. M. O'Brien A G-2-298290 | Greta Operating Company LLC | Greta (4850) | Refugio | 1 | 5.71K | 379K | Nov 2012 – Apr 2026 |
| O'Connor, Thomas (Amoco) G-2-205584 | Greta Operating Company LLC | Greta (5270) | Refugio | 1 | 3.34K | 374K | Jun 2004 – Jun 2012 |
| J. J. O'Brien G-2-260704 | Greta Operating Company LLC | Greta (5780) | Refugio | 1 | 1.21K | 320K | Jan 2011 – May 2019 |
| FVW Heard G-2-207785 | Greta Operating Company LLC | Greta (F-3 West) | Refugio | 1 | 223 | 160K | Oct 2004 – Jun 2019 |
| O'Brien, J. M. G-2-193265 | Greta Operating Company LLC | Greta (O-3) | Refugio | 1 | 159 | 80.3K | Feb 2003 – Dec 2016 |
| Obrien, J. J. -B- G-2-55319 | Greta Operating Company LLC | Greta (L- 8) | Refugio | 1 | 0 | 0 | — |
| Obrien, J. M. -B- G-2-55578 | Greta Operating Company LLC | Greta (O-4) | Refugio | 1 | 0 | 0 | — |
| Obrien, J. M. -B- G-2-74461 | Greta Operating Company LLC | Greta (C-1) | Refugio | 1 | 0 | 408K | Jan 1993 – May 2020 |
| Obrien,j.m.-B-(gas Prod.area-B-) G-2-74593 | Greta Operating Company LLC | Greta (L-13) | Refugio | 1 | 0 | 0 | — |
| Obrien, J. M. -B- G-2-82794 | Greta Operating Company LLC | Greta (900) | Refugio | 1 | 0 | 16.2K | Jan 1993 – Jun 1999 |
| Obrien, J. M. -B- G-2-82795 | Greta Operating Company LLC | Greta (1250) | Refugio | 1 | 0 | 0 | — |
| Obrien, J. M. -B- G-2-85106 | Greta Operating Company LLC | Greta (1300) | Refugio | 1 | 0 | 0 | — |
| Obrien, J. M. -A- G-2-85208 | Greta Operating Company LLC | Greta (900) | Refugio | 1 | 0 | 0 | — |
| Obrien, J. M. -A- G-2-85256 | Greta Operating Company LLC | Greta (1250) | Refugio | 1 | 0 | 28.9K | Jan 1997 – Jan 2018 |
| Obrien, J. M. -B- G-2-99595 | Greta Operating Company LLC | Greta (900) | Refugio | 1 | 0 | 0 | — |
| O'Brien, J.M. -A- G-2-101469 | Greta Operating Company LLC | Greta (O-1) | Refugio | 1 | 0 | 0 | — |
| O'Brien, J.M. -A- G-2-101491 | Greta Operating Company LLC | Greta (O-2 North) | Refugio | 1 | 0 | 0 | — |
| Obrien, J. M. D & E G-2-106112 | Greta Operating Company LLC | Greta, Deep (5600) | Refugio | 1 | 0 | 0 | — |
| Obrien, J.M. -H- G-2-132945 | Greta Operating Company LLC | Greta (L- 8) | Refugio | 1 | 0 | 988 | Feb 1993 – Jun 1993 |
| O'Brien "J&L", J. M. G-2-133722 | Greta Operating Company LLC | Greta (O-4) | Refugio | 1 | 0 | 229K | Jan 1993 – Jun 2013 |
| O'Conner, Thomas G-2-135280 | Greta Operating Company LLC | Greta (L- 5) | Refugio | 1 | 0 | 625K | Jan 1993 – Apr 2026 |
| O'Brien, J. J. C (P) G-2-137754 | Greta Operating Company LLC | Greta (L- 5) | Refugio | 1 | 0 | 190K | Jan 1993 – Jan 2002 |
| O'Brien, J.J. "B" G-2-137761 | Greta Operating Company LLC | Greta (2460) | Refugio | 1 | 0 | 628K | Jan 1993 – Apr 2026 |
| O'Brien, J.M. D&e "D" G-2-141066 | Greta Operating Company LLC | Greta (L- 6 West) | Refugio | 1 | 0 | 6.37K | Jan 1993 – Apr 1993 |
| O'Brien, J.M. J&L "L" G-2-141695 | Greta Operating Company LLC | Greta (L- 5) | Refugio | 1 | 0 | 49.6K | May 1993 – Dec 2018 |
| O'Brien, J.M. A-2 G-2-141804 | Greta Operating Company LLC | Greta (L- 2) | Refugio | 1 | 0 | 772K | Jan 1993 – Aug 2017 |
| O'Brien, J.M. C G-2-141944 | Greta Operating Company LLC | Greta (L- 5) | Refugio | 1 | 0 | 433K | Jan 1993 – Feb 2017 |
| O'Brien B (S), J.M. G-2-143399 | Greta Operating Company LLC | Greta (L- 5) | Refugio | 1 | 0 | 104K | Jan 1993 – Jul 2019 |
| O'Brien, J. B. "B" G-2-144527 | Greta Operating Company LLC | Greta (O-1) | Refugio | 1 | 0 | 94.5K | Jan 1993 – Apr 2013 |
| O'Connor, Tom G-2-144641 | Greta Operating Company LLC | Greta (L- 2) | Refugio | 1 | 0 | 184K | Jan 1993 – Feb 2017 |
| O'Brien, J. J. a (S) G-2-144838 | Greta Operating Company LLC | Greta (O-1) | Refugio | 1 | 0 | 280K | Jan 1993 – Oct 2005 |
| Heard, J. F. B. G-2-145449 | Greta Operating Company LLC | Greta (C-1) | Refugio | 1 | 0 | 7.97K | May 1993 – Jun 1995 |
| Heard, J. F. B. G-2-146737 | Greta Operating Company LLC | Greta (C-5) | Refugio | 1 | 0 | 76K | Aug 1993 – Feb 2026 |
| O'Brien, J.M. D G-2-147384 | Greta Operating Company LLC | Greta (O-5) | Refugio | 1 | 0 | 18.6K | Oct 1993 – Aug 1995 |
| O'Brien, J. J. A G-2-147922 | Greta Operating Company LLC | Greta (L- 3) | Refugio | 1 | 0 | 213K | Oct 1993 – Feb 2014 |
| O'Brien, J.M. A G-2-147933 | Greta Operating Company LLC | Greta (O-3) | Refugio | 1 | 0 | 42.4K | Nov 1993 – May 1995 |
| O'Connor, Tom G-2-147972 | Greta Operating Company LLC | Greta (O-7) | Refugio | 1 | 0 | 148K | Nov 1993 – Jun 2015 |
| Oconnor, Tom G-2-1924 | Greta Operating Company LLC | Greta (F-2 West) | Refugio | 1 | 0 | 0 | — |
| O'Brien, J.M. B G-2-154152 | Greta Operating Company LLC | Greta (O-3) | Refugio | 1 | 0 | 86.2K | Apr 1995 – Feb 2019 |
| O'Brien, J.M. D&e "E" G-2-155985 | Greta Operating Company LLC | Greta (L-15) | Refugio | 1 | 0 | 169K | Sep 1995 – May 2007 |
| O'Brien, J. J. A G-2-156924 | Greta Operating Company LLC | Greta (L- 6 West) | Refugio | 1 | 0 | 148K | Jan 1996 – Feb 2005 |
| O'Brien, J.J. a (S) G-2-157058 | Greta Operating Company LLC | Greta (L- 9) | Refugio | 1 | 0 | 116K | Oct 1995 – Jun 2001 |
| O'Brien, J. M. C G-2-157868 | Greta Operating Company LLC | Greta (L- 5) | Refugio | 1 | 0 | 10.6K | Mar 1996 – Apr 2000 |
| O'Brien, J. J. A(s) G-2-159371 | Greta Operating Company LLC | Greta (L- 8) | Refugio | 1 | 0 | 39.6K | Jun 1996 – Jun 1999 |
| O'Brien, J. M. 'B' G-2-161080 | Greta Operating Company LLC | Greta (C-5) | Refugio | 1 | 0 | 402K | Nov 1996 – Oct 2013 |
| O'Brien, J. M. -A- G-2-175300 | Greta Operating Company LLC | Greta (C-1) | Refugio | 1 | 0 | 219K | Aug 1999 – Apr 2026 |
| Heard-Tex G-2-175379 | Greta Operating Company LLC | Greta (O-1) | Refugio | 1 | 0 | 61.1K | Sep 1999 – Feb 2017 |