Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 10815743 | Depressuriz od for downhole annulus drilling fluid | Yongwang Liu, Zhichuan Guan, Yucai Shi, Hualin Liao | 2020-10-27 |
| 10233695 | Weight-on-bit self-adjusting drill bit | Zhichuan Guan, Yongwang Liu, Huaigang Hu, Yucai Shi, Hualin Liao | 2019-03-19 |
| 9540881 | Method and system for improving drilling speed by using drill speed vibration | Zhichuan Guan, Yongwang Liu, Wenzhong Wei, Yucai Shi, Hongning Zhang | 2017-01-10 |