| 393568Amendment | Nov 8, 1991 | Nov 8, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Duval | Hahl #1 | 13,500 | 13137520 |
| 393555 | Nov 1, 1991 | Nov 1, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Hidalgo | Coates Energy Trust #1 | 12,000 | 21532006 |
| 388948 | Jun 13, 1991 | Jun 13, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Alexander, M. M. #2 | 9,600 | 47935253 |
| 388948Amendment | Jun 13, 1991 | Jun 13, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Alexander, M. M. #2 | 9,600 | 47935253 |
| 388530 | May 31, 1991 | May 31, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L. M. #43 | 9,300 | 47935248 |
| 388138 | May 20, 1991 | May 20, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Frio | West Shiner Ranch #2H | 8,700 | 16332860 |
| 388138Amendment | May 20, 1991 | May 20, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Frio | West Shiner Ranch #2H | 8,700 | 16332860 |
| 387939 | May 14, 1991 | May 14, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Hidalgo | Coates #1R | 12,000 | 21532027 |
| 387939Amendment | May 14, 1991 | May 14, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Hidalgo | Coates #1R | 12,000 | 21532027 |
| 385952 | Mar 21, 1991 | Mar 21, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Dimmit | El Cid "B" #7H | 7,400 | 12732995 |
| 385952Amendment | Mar 21, 1991 | Mar 21, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Dimmit | El Cid "B" #7H | 7,400 | 12732995 |
| 383915 | Jan 28, 1991 | Jan 28, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Starr | Sanchez, A. #1 | 5,000 | 42732464 |
| 382975 | Jan 2, 1991 | Jan 2, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L. M. "A" #42 | 9,500 | 47935144 |
| 382975Amendment | Jan 2, 1991 | Jan 2, 1991 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L. M. "A" #42 | 9,500 | 47935144 |
| 382408 | Dec 14, 1990 | Dec 14, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Casso Ltd #3 | 9,500 | 47935135 |
| 382408Amendment | Dec 14, 1990 | Dec 14, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Casso Ltd #3 | 9,500 | 47935135 |
| 382398Amendment | Dec 14, 1990 | Dec 14, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Hidalgo | Coates #1 | 12,000 | 21532006 |
| 381182 | Nov 16, 1990 | Nov 16, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Alexander, M.M. #1 | 9,200 | 47935126 |
| 378229 | Sep 20, 1990 | Sep 20, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Link Ranch #5 | 7,600 | 47935096 |
| 378229Amendment | Sep 20, 1990 | Sep 20, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Link Ranch #5 | 7,600 | 47935096 |
| 377113 | Aug 24, 1990 | Aug 24, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L.M. #41 | 9,100 | 47935083 |
| 377112 | Aug 24, 1990 | Aug 24, 1990 | Sanchez-O'Brien Oil & Gas Corp. | La Salle | Northway #1 | 8,350 | 28330724 |
| 376375 | Aug 8, 1990 | Aug 8, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Barrera-Leyendecker G/U 2 #2 | 9,500 | 47935074 |
| 376374 | Aug 8, 1990 | Aug 8, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Dimmit | El Cid "A" #6H | 8,250 | 12732919 |
| 375860 | Jul 24, 1990 | Jul 24, 1990 | Sanchez-O'Brien Oil & Gas Corp. | La Salle | El Cid "A" #5H | 8,250 | 28331338 |
| 375860Amendment | Jul 24, 1990 | Jul 24, 1990 | Sanchez-O'Brien Oil & Gas Corp. | La Salle | El Cid "A" #5H | 8,250 | 28331338 |
| 374469 | Jun 13, 1990 | Jun 13, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker-Ramirez GU 1 #3 | 8,900 | 47935056 |
| 374469Amendment | Jun 13, 1990 | Jun 13, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker-Ramirez GU 1 #3 | 8,900 | 47935056 |
| 374037 | Jun 1, 1990 | Jun 1, 1990 | Sanchez-O'Brien Oil & Gas Corp. | La Salle | El Cid "A" #4H | 8,250 | 28331327 |
| 374037Amendment | Jun 1, 1990 | Jun 1, 1990 | Sanchez-O'Brien Oil & Gas Corp. | La Salle | El Cid "A" #4H | 7,000 | 28331327 |
| 373853 | May 25, 1990 | May 25, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hubberd Estate "C" #1 | 10,400 | 47935040 |
| 373791 | May 24, 1990 | May 24, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Dimmit | El Cid Land & Cattle Co. "A" #1 | 7,302 | 12731142 |
| 373438 | May 16, 1990 | May 16, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Martin, S.J. GU #3A | 10,040 | 47932524 |
| 371936 | Apr 6, 1990 | Apr 6, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L.M. #40 | 9,000 | 47935022 |
| 371936Amendment | Apr 6, 1990 | Apr 6, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L.M. #40 | 8,200 | 47935022 |
| 371311 | Mar 22, 1990 | Mar 22, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker #4 | 9,200 | 47935017 |
| 370060 | Feb 20, 1990 | Feb 20, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker-Ramirez Gas Unit 1 #2 | 9,150 | 47934999 |
| 370060Amendment | Feb 20, 1990 | Feb 20, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker-Ramirez Gas Unit 1 #2 | 9,000 | 47934999 |
| 370060Amendment | Feb 20, 1990 | Feb 20, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker-Ramirez GU 1 #2 | 9,000 | 47934999 |
| 369483 | Feb 6, 1990 | Feb 6, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Chambers | B.B. Rogers Gas Unit No. 1 #3 | 11,000 | 07131925 |
| 369276 | Jan 30, 1990 | Jan 30, 1990 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Casso Ltd #2H | 9,200 | 47934884 |
| 366195 | Nov 8, 1989 | Nov 8, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Zapata | Gutierrez #1 | 11,700 | 50532618 |
| 365623 | Oct 25, 1989 | Oct 25, 1989 | Sanchez-O'Brien Oil & Gas Corp. | McMullen | Martin Gas Unit 1 #1 | 13,500 | 31132799 |
| 365257 | Oct 17, 1989 | Oct 17, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Barrera-Leyendecker G/U 1 #2 | 9,700 | 47934933 |
| 365257Amendment | Oct 17, 1989 | Oct 17, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Barrera-Leyendecker G/U 1 #2 | 9,700 | 47934933 |
| 364697 | Oct 3, 1989 | Oct 3, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Duval | Longoria, M.T. #1 | 17,500 | 13137280 |
| 364207 | Sep 21, 1989 | Sep 21, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hubberd Estate "B" #2 | 9,900 | 47934915 |
| 364207Amendment | Sep 21, 1989 | Sep 21, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hubberd Estate "B" #2 | 9,900 | 47934915 |
| 363632 | Sep 6, 1989 | Sep 6, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L.M. #39 | 9,300 | 47934908 |
| 363075 | Aug 21, 1989 | Aug 21, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Barrera-Leyendecker G/U 2 #1 | 9,600 | 47934904 |
| 363075Amendment | Aug 21, 1989 | Aug 21, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Barrera-Leyendecker G/U 2 #1 | 9,600 | 47934904 |
| 362414 | Aug 4, 1989 | Aug 4, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L.M. #38 | 8,000 | 47934901 |
| 362188 | Jul 31, 1989 | Jul 31, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hein Estate #1 | 9,300 | 47934897 |
| 361036 | Jun 30, 1989 | Jun 30, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Casso Ltd. #2 | 9,200 | 47934884 |
| 361036Amendment | Jun 30, 1989 | Jun 30, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Casso Ltd. #2 | 9,200 | 47934884 |
| 360584Amendment | Jun 20, 1989 | Jun 20, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Jim Hogg | Montalvo #1 | 14,300 | 24731869 |
| 360427 | Jun 14, 1989 | Jun 14, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L.M. #36 | 9,200 | 47934874 |
| 360426 | Jun 14, 1989 | Jun 14, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L.M. #37 | 9,300 | 47934875 |
| 360272 | Jun 9, 1989 | Jun 9, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker #3 | 10,300 | 47934869 |
| 360272Amendment | Jun 9, 1989 | Jun 9, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker #3 | 10,300 | 47934869 |
| 358943 | May 4, 1989 | May 4, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Barrera-Ramirez Gas Unit No. 1 #1 | 9,700 | 47934854 |
| 358943Amendment | May 4, 1989 | May 4, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Barrera-Ramirez Gas Unit No. 1 #1 | 9,700 | 47934854 |
| 358942 | May 4, 1989 | May 4, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hubberd Estate "B" #1 | 10,000 | 47934855 |
| 358533 | Apr 24, 1989 | Apr 24, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L. M. #35 | 9,500 | 47934846 |
| 358032 | Apr 11, 1989 | Apr 11, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Casso Ltd. #1 | 8,900 | 47934842 |
| 358032Amendment | Apr 11, 1989 | Apr 11, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Casso Ltd. #1 | 8,900 | 47934842 |
| 357176 | Mar 17, 1989 | Mar 17, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L.M. #34 | 9,500 | 47934837 |
| 355460 | Jan 24, 1989 | Jan 24, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Sob Min Fee #1 | 9,600 | 47934811 |
| 355252 | Jan 17, 1989 | Jan 17, 1989 | Sanchez-O'Brien Oil & Gas Corp. | Goliad | Albrecht, V. #1 | 7,000 | 17532362 |
| 354800 | Dec 30, 1988 | Dec 30, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Zapata | Martinez Trust #1 | 9,900 | 50532518 |
| 354389 | Dec 16, 1988 | Dec 16, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | O'Keefe No. 3 #3 | 7,500 | 47934793 |
| 353878 | Dec 2, 1988 | Dec 2, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker #2 | 9,500 | 47934786 |
| 353878Amendment | Dec 2, 1988 | Dec 2, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker #2 | 9,500 | 47934786 |
| 353126 | Nov 8, 1988 | Nov 8, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Link Ranch #4 | 8,200 | 47934774 |
| 352561 | Oct 21, 1988 | Oct 21, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L. M. #33 | 8,300 | 47934763 |
| 352007 | Oct 7, 1988 | Oct 7, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Live Oak | Crawford Estate #2 | 9,500 | 29731619 |
| 352007Amendment | Oct 7, 1988 | Oct 7, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Live Oak | Crawford Estate #2 | 9,500 | 29731619 |
| 351219 | Sep 15, 1988 | Sep 15, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L. M. #30 | 8,600 | 47934746 |
| 350435 | Aug 24, 1988 | Aug 24, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Calhoun | Welder, J. #1 | 10,000 | 05731460 |
| 350434 | Aug 24, 1988 | Aug 24, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Hereford, L. M. #32 | 8,800 | 47934735 |
| 350220 | Aug 16, 1988 | Aug 16, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Leyendecker #1 | 10,000 | 47934732 |
| 347607 | Jun 13, 1988 | Jun 13, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Link Ranch #3 | 8,000 | 47934703 |
| 346983 | May 25, 1988 | May 25, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Schwarz #1 | 8,400 | 47934690 |
| 345050 | Apr 11, 1988 | Apr 11, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | O'Keefe #2 | 8,300 | 47934667 |
| 344397 | Mar 28, 1988 | Mar 28, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Live Oak | George West GU 2 #2 | 9,500 | 29731619 |
| 344397Amendment | Mar 28, 1988 | Mar 28, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Live Oak | George West GU 2 #2 | 9,500 | 29731619 |
| 343931 | Mar 15, 1988 | Mar 15, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | San Isidro Farm #2 | 8,800 | 47934656 |
| 343931Amendment | Mar 15, 1988 | Mar 15, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | San Isidro Farm #2 | 8,800 | 47934656 |
| 343739 | Mar 10, 1988 | Mar 10, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Live Oak | Bodden, Charles L. #5 | 8,765 | 29732127 |
| 342861 | Feb 18, 1988 | Feb 18, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Link Ranch #2 | 8,000 | 47934646 |
| 341334 | Jan 14, 1988 | Jan 14, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | O'Keefe #1 | 8,300 | 47934631 |
| 341334Amendment | Jan 14, 1988 | Jan 14, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | O'Keefe #1 | 8,300 | 47934631 |
| 341145 | Jan 7, 1988 | Jan 7, 1988 | Sanchez-O'Brien Oil & Gas Corp. | Webb | San Isidro Farm #1 | 8,900 | 47934627 |
| 339859 | Dec 9, 1987 | Dec 9, 1987 | Sanchez-O'Brien Oil & Gas Corp. | Live Oak | Bodden, Charles L. #3 | 9,025 | 29730985 |
| 339331 | Nov 24, 1987 | Nov 24, 1987 | Sanchez-O'Brien Oil & Gas Corp. | Zapata | White #1 | 11,200 | 50532397 |
| 339331Amendment | Nov 24, 1987 | Nov 24, 1987 | Sanchez-O'Brien Oil & Gas Corp. | Zapata | White #1 | 11,200 | 50532397 |
| 338152 | Oct 30, 1987 | Oct 30, 1987 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Link Ranch #1 | 8,200 | 47934599 |
| 338152Amendment | Oct 30, 1987 | Oct 30, 1987 | Sanchez-O'Brien Oil & Gas Corp. | Webb | Link Ranch #1 | 8,200 | 47934599 |
| 337525 | Oct 19, 1987 | Oct 19, 1987 | Sanchez-O'Brien Oil & Gas Corp. | McMullen | Acker, W. #1 | 9,200 | 31132599 |
| 337320 | Oct 14, 1987 | Oct 14, 1987 | Sanchez-O'Brien Oil & Gas Corp. | Matagorda | Bunk, J. F. #1 | 9,812 | 32131535 |