| Prentice Northeast Unit #27542-445-31630 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | ActiveOil | 6,870 | Oct 31, 1990 | — | — |
| Prentice Northeast Unit #27242-445-31631 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | PluggedOil | 7,000 | Oct 31, 1990 | — | — |
| Keystone Cattle Co. #378 HHZ42-495-32340 | Highmark Energy Operating LLC | Winkler, TXFlying -W- (Wolfcamp) | ActiveOil | 10,040 | Aug 22, 1990 | — | — |
| Graham #142-357-30948 | Highmark Energy Operating LLC | Ochiltree, TXPeery (Cleveland) | ActiveOil | 9,330 | Aug 20, 1990 | — | — |
| Conroe Field Unit #352942-339-30456 | Highmark Energy Operating LLC | Montgomery, TXConroe | Temporarily abandonedGas | 5,272 | Jun 22, 1990 | — | — |
| University -F- #4L42-003-07314 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Clear Fork) | ActiveOil | 9,915 | Apr 11, 1990 | — | — |
| Conroe Field Unit #193442-339-30488 | Highmark Energy Operating LLC | Montgomery, TXConroe | PluggedOil | 5,700 | Jan 9, 1990 | — | — |
| Conroe Field Unit #1404A42-339-00757 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,126 | Sep 21, 1989 | — | — |
| University 141A 173 #842-003-05463 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Devonian) | Shut inOil | 11,900 | Sep 12, 1989 | — | — |
| Bitler-Lowe Clearfork Unit #5CR42-003-36500 | Highmark Energy Operating LLC | Andrews, TXFullerton | PluggedOil | 7,200 | Sep 6, 1989 | — | — |
| Bitler-Lowe Clearfork Unit #a 2CR42-003-36492 | Highmark Energy Operating LLC | Andrews, TXFullerton | ActiveInjection | 7,250 | Aug 28, 1989 | — | — |
| Conroe Field Unit #306A42-339-00713 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,159 | Aug 24, 1989 | — | — |
| Bitler-Lowe Clearfork Unit #1CR42-003-36481 | Highmark Energy Operating LLC | Andrews, TXFullerton | ActiveInjection | 7,200 | Aug 11, 1989 | — | — |
| Conroe Field Unit #1959A42-339-30834 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,255 | May 9, 1989 | — | — |
| Conroe Field Unit #354142-339-30830 | Highmark Energy Operating LLC | Montgomery, TXConroe | ActiveOil | 5,235 | Mar 20, 1989 | — | — |
| Bitler-Lowe -B- #1142-003-36313 | Highmark Energy Operating LLC | Andrews, TXFullerton | Shut inOil | 7,300 | Feb 13, 1989 | — | — |
| Conroe Field Unit #112142-339-30821 | Highmark Energy Operating LLC | Montgomery, TXConroe | ActiveOil | 5,255 | Nov 4, 1988 | — | — |
| University 141A 173 #a 3W42-003-05346 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Devonian) | Shut inOil | 10,618 | Aug 18, 1988 | — | — |
| University 154 #842-003-05372 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Ellenburger) | Shut inOil | 11,805 | Aug 18, 1988 | — | — |
| Prentice Northeast Unit #26842-445-31490 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | PluggedOil | 7,000 | Jul 25, 1988 | — | — |
| Prentice Northeast Unit #26542-445-31491 | Highmark Energy Operating LLC | Terry, TXPrentice (6700) | PluggedOil | 7,000 | Jul 25, 1988 | — | — |
| Prentice Northeast Unit #26942-501-33281 | Highmark Energy Operating LLC | Yoakum, TXPrentice (6700) | ActiveOil | 6,810 | Jul 25, 1988 | — | — |
| Bitler-Lowe Clearfork Unit #4CR42-003-36210 | Highmark Energy Operating LLC | Andrews, TXFullerton | PluggedOil | 7,200 | Jul 19, 1988 | — | — |
| University -154- #1942-003-35972 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Devonian) | Shut inOil | 9,900 | Jul 18, 1988 | — | — |
| Miles B #2 D42-003-03359 | Highmark Energy Operating LLC | Andrews, TXDeep Rock (Devonian) | Shut inOil | 12,235 | May 17, 1988 | — | — |
| Bitler-Lowe -B- #1042-003-36137 | Highmark Energy Operating LLC | Andrews, TXFullerton | PluggedOil | 7,200 | Apr 28, 1988 | — | — |
| Conroe Field Unit #391142-339-30810 | Highmark Energy Operating LLC | Montgomery, TXConroe | ActiveGas | 5,220 | Apr 5, 1988 | — | — |
| Southland Royalty -C- #242-003-03378 | Highmark Energy Operating LLC | Andrews, TXWallen (San Andres) | ActiveOil | 9,360 | Mar 25, 1988 | — | — |
| University -154- #2042-003-36105 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Devonian) | PluggedOil | 9,975 | Mar 23, 1988 | — | — |
| Conroe Field Unit #11242-339-30808 | Highmark Energy Operating LLC | Montgomery, TXConroe | ActiveOil | 5,220 | Mar 11, 1988 | — | — |
| Miles Hayden -a- #142-003-03355 | Highmark Energy Operating LLC | Andrews, TXDeep Rock (Devonian) | Shut inOil | 12,260 | Mar 2, 1988 | — | — |
| Conroe Field Unit #208342-339-30807 | Highmark Energy Operating LLC | Montgomery, TXConroe | PluggedOil | 5,300 | Mar 1, 1988 | — | — |
| Conroe Field Unit #231442-339-30802 | Highmark Energy Operating LLC | Montgomery, TXConroe | ActiveOil | 5,206 | Feb 1, 1988 | — | — |
| Conroe Field Unit #2724A42-339-30794 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,299 | Jan 22, 1988 | — | — |
| Conroe Field Unit #195742-339-30799 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,220 | Jan 18, 1988 | — | — |
| Conroe Field Unit #2118D42-339-30690 | Highmark Energy Operating LLC | Montgomery, TXConroe | ActiveInjection | 9,125 | Jan 13, 1988 | — | — |
| Conroe Field Unit #362342-339-30792 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,200 | Dec 14, 1987 | — | — |
| Shafter Lake Clearfork Unit #30142-003-07680 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Clear Fork) | Shut inOil | 7,073 | Oct 27, 1987 | — | — |
| Conroe Field Unit #362242-339-30785 | Highmark Energy Operating LLC | Montgomery, TXConroe | Temporarily abandonedGas | 5,200 | Oct 14, 1987 | — | — |
| University 155 #942-003-35918 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Devonian) | Shut inOil | 9,900 | Sep 14, 1987 | — | — |
| Conroe Field Unit #281342-339-30782 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,212 | Sep 11, 1987 | — | — |
| Prentice Northeast Unit #26442-501-33282 | Highmark Energy Operating LLC | Yoakum, TXPrentice (6700) | PluggedOil | 7,000 | Sep 8, 1987 | — | — |
| Conroe Field Unit #195542-339-30778 | Highmark Energy Operating LLC | Montgomery, TXConroe | ActiveOil | 5,200 | Jul 20, 1987 | — | — |
| Conroe Field Unit #551042-339-30777 | Highmark Energy Operating LLC | Montgomery, TXConroe | PluggedOil | 5,200 | Jul 10, 1987 | — | — |
| Conroe Field Unit #353942-339-30817 | Highmark Energy Operating LLC | Montgomery, TXConroe | ActiveOil | 5,500 | Jul 1, 1987 | — | — |
| Conroe Field Unit #195442-339-30775 | Highmark Energy Operating LLC | Montgomery, TXConroe | ActiveOil | 5,200 | Jun 23, 1987 | — | — |
| Conroe Field Unit #195342-339-30774 | Highmark Energy Operating LLC | Montgomery, TXConroe | Temporarily abandonedGas | 5,200 | Jun 12, 1987 | — | — |
| Conroe Field Unit #371642-339-30772 | Highmark Energy Operating LLC | Montgomery, TXConroe | Shut inOil | 5,100 | Jun 10, 1987 | — | — |
| Conroe Field Unit #381642-339-30773 | Highmark Energy Operating LLC | Montgomery, TXConroe | Temporarily abandonedGas | 5,160 | Jun 2, 1987 | — | — |
| University 153 #642-003-05364 | Highmark Energy Operating LLC | Andrews, TXShafter Lake (Devonian) | Shut inOil | 9,888 | May 20, 1987 | — | — |