Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 8127859 | Use of swellable material in an annular seal element to prevent leakage in a subterranean well | David B. Allison, Michael MacDonald, Alf K. Sevre, Earl Webb | 2012-03-06 |
| 7841417 | Use of swellable material in an annular seal element to prevent leakage in a subterranean well | David B. Allison, Michael MacDonald, Alf K. Sevre, Earl Webb | 2010-11-30 |