Issued Patents 1989
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4888120 | Water-based drilling and well-servicing fluids with swellable, synthetic layer silicates | Heinz Mueller, Claus-Peter Herold, Stephan van Tapavizca, Wolfgang von Rybinski, Winfried Wichelhaus | 1989-12-19 |