| Tunnell, A. R. 59 O-5-3217 | Union Oil Company of California only | Van (Austin Chalk) | Van Zandt | 8 | 125K | 281K | by Jan 1993 – Nov 2009 |
| Braemar O-11-67438 | Union Oil Company of California only | Blackwatch (San Andres) | Gaines | 3 | 123K | 42.2K | Sep 1995 – Sep 1997 |
| Crim, J. R. 16 O-5-3595 | Union Oil Company of California only | Van (Upper Carlile) | Van Zandt | 2 | 118K | 185K | Oct 1997 – Sep 2007 |
| Cartwright-Moore Unit O-3-23512 | Union Pacific Resources Company only | Giddings (Buda) | Milam | 1 | 115K | 50.4K | Jun 1997 – Dec 1998 |
| Parker, J. E. -G- O-10-247 | Union Oil Company of California only | Andrews (Pennsylvanian) | Andrews | 3 | 112K | 107K | by Jan 1993 – Sep 1995 |
| Peters, R. H. 29 O-5-3649 | Union Oil Company of California only | Van (Upper Carlile) | Van Zandt | 3 | 110K | 102K | Feb 1998 – Oct 1999 |
| Force, E. J. Unit G-3-118949 | Tri-Union Development Corp. only | Alvin, North (8550) | Brazoria | 1 | 109K | 261K | by Jan 1993 – Nov 1998 |
| Strickland O-3-22521 | Tri-Union Development Corp. only | Alvin, North (7900) | Brazoria | 1 | 107K | 64.2K | Oct 1994 – Aug 1997 |
| Cordova-Union O-9-896 | XOG Operating LLC only | McCamey | Upton | 4 | 106K | 380 | by Jan 1993 – Apr 2016 |
| Chapman O-13-31704 | CTL Production, Inc. only | Union Cemetery (Strawn) | Montague | 1 | 98.4K | 0 | Jul 2010 – Jul 2026 |
| Leonard, J. H. 30 O-5-3607 | Union Oil Company of California only | Van (Upper Carlile) | Van Zandt | 2 | 89.8K | 45.2K | Dec 1997 – Feb 2000 |
| Gibbs Bros. Unit G-6-149857 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Newton | 1 | 88.2K | 472K | May 1994 – Jan 1999 |
| Maggie Unit O-3-23596 | Union Pacific Resources Company only | Giddings (Austin Chalk-3) | Bastrop | 1 | 88.1K | 39.6K | Feb 1998 – Feb 1999 |
| Parker, J.E. "V" O-10-34086 | Union Oil Company of California only | Andrews (Pennsylvanian) | Andrews | 4 | 87.7K | 135K | Jan 1994 – Sep 1995 |
| Parker, J.E. "C" O-10-34111 | Union Oil Company of California only | Andrews (Pennsylvanian) | Andrews | 2 | 85.2K | 96.9K | Feb 1994 – Sep 1995 |
| Arco-Fee a-990 Unit G-6-153675 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Jasper | 1 | 77.7K | 1.04M | Dec 1994 – Aug 1998 |
| Grant O-3-23533 | Union Pacific Resources Company only | Giddings (Buda) | Brazos | 1 | 77K | 90.7K | Sep 1997 – Sep 1998 |
| Magers, A. F. 18 O-5-1174 | Union Oil Company of California only | Van | Van Zandt | 5 | 76.3K | 19.7K | by Jan 1993 – May 2019 |
| Union Ranch G-4-251688 | Mountain V Texas, LLC only | Tiffany (Wilcox Carrizo) | Webb | 1 | 75K | 5.61M | Mar 2009 – Aug 2026 |
| Dietz-OL Unit O-3-22105 | Union Pacific Resources Company only | Giddings (Austin Chalk-3) | Washington | 1 | 74.2K | 600K | Jul 1993 – Oct 1993 |
| White, R. V. 502 O-5-1212 | Union Oil Company of California only | Van | Van Zandt | 4 | 71.6K | 110K | by Jan 1993 – Jan 2008 |
| State Tract 563-L O-2-6865 | Tri-Union Development Corp. only | Matagorda Block 563-L (6936) | Matgrda IS-LB | 1 | 70.7K | 158K | by Jan 1993 – Mar 1999 |
| Carpenter O-6-13387 | Reynolds Drilling Co., Inc. only | Old Union (Morningsport) | Bowie | 1 | 70.3K | 0 | Dec 1994 – Jan 2008 |
| Tunnell, I. P. 300 O-5-3467 | Union Oil Company of California only | Van (Pecan Gap) | Van Zandt | 5 | 68K | 177K | Dec 1993 – Mar 2011 |
| Teinert-Kunze Unit O-3-21604 | Union Pacific Resources Company only | Giddings (Austin Chalk-3) | Fayette | 1 | 67.6K | 285K | by Jan 1993 – Feb 1998 |
| Hoelscher, Alice B. G-3-143662 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Burleson | 1 | 67.3K | 723K | by Jan 1993 – May 1996 |
| Parker, J. E. -A- O-10-31375 | Union Oil Company of California only | Parker (Pennsylvanian) | Andrews | 2 | 66.5K | 52K | by Jan 1993 – Aug 1994 |
| Tatsch O-1-13721 | Union Pacific Resources Company only | Pearsall (Austin Chalk) | Frio | 1 | 65.6K | 65.2K | Mar 1993 – Dec 1998 |
| Bourg O-10-25156 | Tacor Resources Inc only | Union | Andrews | 3 | 65.5K | 99.8K | by Jan 1993 – Dec 2016 |
| Fowler, E. L. 302 O-5-3496 | Union Oil Company of California only | Van (Pecan Gap) | Van Zandt | 3 | 65.3K | 73.2K | Sep 1994 – Jun 2011 |
| Bscu USA 27316 G-6-156998 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Sabine | 1 | 65K | 709K | Mar 1995 – Dec 1998 |
| Scarborough Unit O-10-34749 | Texland Petroleum, L.P. only | Union | Andrews | 2 | 64.6K | 132K | Oct 1995 – Aug 2026 |
| Blacktail Unit O-3-23474 | Union Pacific Resources Company only | Giddings (Buda) | Robertson | 1 | 64.2K | 33.2K | Feb 1998 – Jul 1998 |
| Biles, J. D. O-10-11129 | Reliance Energy, Inc. only | Union | Andrews | 3 | 63.2K | 172K | by Jan 1993 – May 2026 |
| Welch (Union) A O-9-11944 | Endeavor Energy Resources L.P. only | Spraberry (Trend Area) | Reagan | 1 | 62.7K | 192K | by Jan 1993 – Jan 2024 |
| Parker, J. E. -C- O-10-34699 | Union Oil Company of California only | Andrews (Wolfcamp-Penn.) | Andrews | 2 | 62.6K | 80K | Oct 1995 – Nov 1997 |
| Maxfield, A. G. 38 O-5-3618 | Union Oil Company of California only | Van (Rodessa) | Van Zandt | 5 | 62.6K | 81.8K | Mar 1998 – Oct 1999 |
| J. E. Parker "D" Unit O-10-34067 | Union Oil Company of California only | Andrews (Pennsylvanian) | Andrews | 1 | 62.4K | 50.5K | Jan 1994 – Sep 1995 |
| Arco-Vastar Unit A-1008 O-6-12958 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Newton | 1 | 62K | 287K | by Jan 1993 – Sep 1995 |
| Maxfield, A. G. 38 O-5-3634 | Union Oil Company of California only | Van (Upper Carlile) | Van Zandt | 1 | 61.5K | 30.8K | May 1998 – Oct 1999 |
| Roosevelt Unit G-3-151956 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Fayette | 1 | 61.5K | 671K | May 1994 – Sep 1999 |
| Peters, R. 29 O-5-3666 | Union Oil Company of California only | Van (James) | Van Zandt | 1 | 61.1K | 43.1K | Mar 1999 – Nov 2014 |
| Leonard, J. H. 30 O-5-3606 | Union Oil Company of California only | Van (Rodessa) | Van Zandt | 2 | 60.6K | 351K | Dec 1997 – Oct 2008 |
| Parker, J. E. "E" Unit O-10-33742 | Union Oil Company of California only | Andrews (Pennsylvanian) | Andrews | 1 | 60.2K | 42.8K | Mar 1993 – Sep 1995 |
| Somerled O-11-67434 | Union Oil Company of California only | Blackwatch (San Andres) | Gaines | 2 | 60.1K | 21.9K | Sep 1995 – Sep 1997 |
| Embesi Unit G-3-174197 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Fayette | 1 | 59.9K | 502K | Jun 1999 – Oct 1999 |
| Parker, J. E. -V- O-10-34698 | Union Oil Company of California only | Andrews (Wolfcamp-Penn.) | Andrews | 4 | 59.1K | 134K | Oct 1995 – Nov 1997 |
| Logswhite O-10-13895 | J. D. Gas, Inc. only | Union | Andrews | 4 | 58.6K | 110K | by Jan 1993 – Aug 2026 |
| Crim, R, C, 28 O-5-3664 | Union Oil Company of California only | Van (Carlisle) | Van Zandt | 2 | 57.9K | 57.2K | Oct 1998 – Oct 1999 |
| The Pines, Inc.-Karisch Unit O-3-21223 | Union Pacific Resources Company only | Giddings (Austin Chalk-3) | Fayette | 1 | 57.9K | 412K | by Jan 1993 – Jan 1998 |