Strong salt-resistant self-degradation plugging agent for water-based drilling fluid and preparation method therefor
US12371603B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 2025 |
| Grant date | Jul 29, 2025 |
| Priority date | — |
| Expiry date | Mar 5, 2045 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K8/206
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Disclosed are a strong salt-resistant self-degradation plugging agent for water-based drilling fluid and a preparation method therefor. The preparation method includes: modifying unsaturated polyhydroxyalkanoate by using 2-acrylamide-2-methylpropanesulfonic acid to prepare modified polyhydroxyalkanoate; modifying lignin by using an ammonium halide salt to prepare quaternized lignin; and melting and blending the quaternized lignin and the modified polyhydroxyalkanoate to obtain the strong salt-resistant self-degradation plugging agent for water-based drilling fluid. The preparation method is mature and reliable, and is suitable for industrial production. The plugging agent has strong salt resistance and good stability, and has a degradation rate less than 15% within 7 days, which can effectively plug micron-sized fractures in shale formations. Meanwhile, the plugging agent may be directly added to the water-based drilling fluid, and has little effect on the rheology. With addition of the plugging agent, the high-temperature and high-pressure filtration loss of the drilling fluid is significantly reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.