| Jackson SP & KK -C- #242-195-31427 | Highmark Energy Operating LLC | Hansford, TXHansford North (Morrow) | ActiveGas | 7,907 | Mar 27, 2000 | — | — |
| Prentice Northeast Unit #57742-445-31913 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveInjection | 7,329 | Mar 23, 2000 | — | — |
| Prentice Northeast Unit #53642-445-31914 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 6,700 | Mar 23, 2000 | — | — |
| Prentice Northeast Unit #29642-445-31915 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,300 | Mar 23, 2000 | — | — |
| Prentice Northeast Unit #58542-445-31916 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveInjection | 7,355 | Mar 23, 2000 | — | — |
| Prentice Northeast Unit #55242-445-31917 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,305 | Mar 23, 2000 | — | — |
| Barrett 93 #242-195-31418 | Highmark Energy Operating LLC | Hansford, TXHansford (Morrow Lower) | ActiveGas | 8,048 | Feb 17, 2000 | — | — |
| Phelps-Bryan 119 #142-195-31422 | Highmark Energy Operating LLC | Hansford, TXHansford (Morrow Upper) | ActiveGas | 7,500 | Feb 14, 2000 | — | — |
| Shafter Lake Clearfork Unit #725W42-003-38569 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Clear Fork) | Shut inOil | 7,073 | Jan 28, 2000 | — | — |
| Prentice Northeast Unit #66742-445-31723 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,273 | Oct 29, 1999 | — | — |
| Prentice Northeast Unit #59442-445-31888 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | Shut inOil | 7,460 | Oct 29, 1999 | — | — |
| Prentice Northeast Unit #55542-445-31889 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,360 | Oct 29, 1999 | — | — |
| Prentice Northeast Unit #29542-445-31890 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | PluggedOil | 7,400 | Oct 29, 1999 | — | — |
| Alma #842-135-02441 | Highmark Energy Operating LLC | Ector, TXTXL (Tubb) | ActiveOil | 9,821 | Oct 27, 1999 | — | — |
| Piper Ola P. #632142-295-32513 | Highmark Energy Operating LLC | Lipscomb, TXLipscomb (Cleveland) | Temporarily abandonedGas | 10,300 | Sep 8, 1999 | — | — |
| Prentice Northeast Unit #181HHZ42-445-31311 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | PluggedOil | 6,750 | Aug 23, 1999 | — | — |
| Prentice Northeast Unit #58242-445-31878 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | Shut inOil | 7,270 | Jul 27, 1999 | — | — |
| Prentice Northeast Unit #57542-445-31879 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,190 | Jul 27, 1999 | — | — |
| Prentice Northeast Unit #59242-445-31880 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,485 | Jul 27, 1999 | — | — |
| Prentice Northeast Unit #55742-445-31881 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,365 | Jul 27, 1999 | — | — |
| Prentice Northeast Unit #50742-445-31882 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,370 | Jul 27, 1999 | — | — |
| Prentice Northeast Unit #154HZ42-445-31075 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | Shut inOil | 6,890 | Aug 25, 1998 | — | — |
| Shafter Lake Clearfork Unit #407142-003-38436 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Clear Fork) | Shut inOil | 7,023 | May 27, 1998 | — | — |
| Collier H. J. -D- #142-195-00436 | Highmark Energy Operating LLC | Hansford, TXTexas Hugoton | ActiveGas | 4,545 | Feb 27, 1998 | — | — |
| Averitt #142-135-37597 | Highmark Energy Operating LLC | Ector, TXCowden South | ActiveOil | 4,900 | Feb 4, 1998 | — | — |
| Frazier A. H. #342-195-00295 | Highmark Energy Operating LLC | Hansford, TXTexas Hugoton | ActiveGas | 4,574 | Jan 30, 1998 | — | — |
| Hansford GU 27 #142-195-00474 | Highmark Energy Operating LLC | Hansford, TXHansford (Morrow Upper) | Temporarily abandonedGas | 7,700 | Jan 30, 1998 | — | — |
| Rogers Helen #3 U42-357-02380 | Highmark Energy Operating LLC | Ochiltree, TXDude Wilson (Novi Lime) | ActiveGas | 8,500 | Jan 20, 1998 | — | — |
| Dude Wilson Gas Unit 6 #342-357-32229 | Highmark Energy Operating LLC | Ochiltree, TXPan Petro (Cleveland) | ActiveGas | 7,150 | Dec 29, 1997 | — | — |
| Dude Wilson Gas Unit 6 #442-357-32230 | Highmark Energy Operating LLC | Ochiltree, TXPan Petro (Cleveland) | ActiveGas | 7,150 | Dec 29, 1997 | — | — |
| Dude Wilson Gas Unit 6 #542-357-32231 | Highmark Energy Operating LLC | Ochiltree, TXPan Petro (Cleveland) | Temporarily abandonedGas | 7,200 | Dec 29, 1997 | — | — |
| Shafter Lake Clearfork Unit #425W42-003-38283 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Clear Fork) | ActiveInjection | 7,030 | Sep 19, 1997 | — | — |
| Shafter Lake Clearfork Unit #424W42-003-38284 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Clear Fork) | ActiveInjection | 7,029 | Sep 19, 1997 | — | — |
| Shafter Lake Clearfork Unit #325W42-003-38285 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Clear Fork) | Shut inOil | 7,010 | Sep 19, 1997 | — | — |
| Prentice Northeast Unit #55442-445-31840 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,300 | Sep 12, 1997 | — | — |
| Prentice Northeast Unit #28742-445-31841 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveInjection | 7,440 | Sep 9, 1997 | — | — |
| Prentice Northeast Unit #26242-445-31834 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,187 | Aug 27, 1997 | — | — |
| Prentice Northeast Unit #26342-445-31835 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,243 | Aug 27, 1997 | — | — |
| Prentice Northeast Unit #27342-445-31836 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,410 | Aug 27, 1997 | — | — |
| Prentice Northeast Unit #52942-445-31837 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveInjection | 7,413 | Aug 27, 1997 | — | — |
| Prentice Northeast Unit #61442-445-31838 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 7,302 | Aug 27, 1997 | — | — |
| Dude Wilson Gas Unit No. 1 #442-357-32219 | Highmark Energy Operating LLC | Ochiltree, TXPan Petro (Cleveland) | ActiveGas | 7,600 | Aug 22, 1997 | — | — |
| Conroe Field Unit #220542-339-00635 | Highmark Energy Operating LLC | Montgomery, TXConroe | Temporarily abandonedGas | 5,149 | Aug 19, 1997 | — | — |
| Conroe Field Unit #3540A42-339-30831 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,230 | Aug 19, 1997 | — | — |
| Conroe Field Unit #350442-339-00663 | Highmark Energy Operating LLC | Montgomery, TXConroe | Temporarily abandonedGas | 5,100 | Aug 18, 1997 | — | — |
| Conroe Field Unit #411A42-339-30115 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,200 | Aug 13, 1997 | — | — |
| Conroe Field Unit #40442-339-00488 | Highmark Energy Operating LLC | Montgomery, TXConroe | Temporarily abandonedGas | 5,182 | Aug 8, 1997 | — | — |
| Conroe Field Unit #21442-339-00718 | Highmark Energy Operating LLC | Montgomery, TXConroe | Temporarily abandonedGas | 5,144 | Aug 7, 1997 | — | — |
| Wilson Dude GU -4- #442-357-32216 | Highmark Energy Operating LLC | Ochiltree, TXPan Petro (Cleveland) | ActiveGas | 7,150 | Aug 6, 1997 | — | — |
| Wilson Dude GU -4- #542-357-32217 | Highmark Energy Operating LLC | Ochiltree, TXPan Petro (Cleveland) | Temporarily abandonedGas | 7,150 | Aug 5, 1997 | — | — |