E21B 21/001
Methods or apparatus for flushing boreholes: specially adapted for underwater drilling
Official title: {specially adapted for underwater drilling (dual gradient drilling E21B21/082)}
E21B21/001 (Methods or apparatus for flushing boreholes: specially adapted for underwater drilling) appears on 328 US grants and 261 published applications in this corpus.
Search patents in E21B- Granted patents
- 328
- Published applications
- 261
- Assignees
- 137
- Inventors
- 486
- Latest grant
- 27 Jan 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 5 | 0 |
| 1978 | 5 | 0 |
| 1979 | 4 | 0 |
| 1980 | 5 | 0 |
| 1981 | 5 | 0 |
| 1982 | 0 | 0 |
| 1983 | 1 | 0 |
| 1984 | 5 | 0 |
| 1985 | 4 | 0 |
| 1986 | 5 | 0 |
| 1987 | 4 | 0 |
| 1988 | 2 | 0 |
| 1989 | 4 | 0 |
| 1990 | 0 | 0 |
| 1991 | 3 | 0 |
| 1992 | 4 | 0 |
| 1993 | 2 | 0 |
| 1994 | 3 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 2 | 0 |
| 1999 | 1 | 0 |
| 2000 | 4 | 0 |
| 2001 | 9 | 2 |
| 2002 | 12 | 10 |
| 2003 | 8 | 9 |
| 2004 | 4 | 8 |
| 2005 | 9 | 3 |
| 2006 | 4 | 8 |
| 2007 | 6 | 5 |
| 2008 | 3 | 8 |
| 2009 | 2 | 5 |
| 2010 | 3 | 3 |
| 2011 | 8 | 12 |
| 2012 | 9 | 9 |
| 2013 | 11 | 11 |
| 2014 | 9 | 20 |
| 2015 | 14 | 18 |
| 2016 | 20 | 18 |
| 2017 | 20 | 16 |
| 2018 | 15 | 16 |
| 2019 | 14 | 18 |
| 2020 | 18 | 18 |
| 2021 | 11 | 10 |
| 2022 | 16 | 12 |
| 2023 | 12 | 6 |
| 2024 | 10 | 10 |
| 2025 | 9 | 4 |
| 2026 | 1 | 2 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Rotating and reciprocating swivel apparatus and method27 Jan 2026US 12,534,972 B2Mako Rentals, Inc.
- Device and method for rapidly regulating downhole pressure after kick in deepwater shallow open-circuit drilling25 Nov 2025US 12,480,371 B1Beijing University of Chemical Technology
- Multi-mode pumped riser arrangement and methods8 Jul 2025US 12,352,112 B2Enhanced Drilling AS
- Multi-mode pumped riser arrangement and methods8 Jul 2025US 12,352,113 B2Enhanced Drilling AS
- Rigless drilling and wellhead installation20 May 2025US 12,305,513 B2Vetco Gray Scandinavia.AS
- Riser-less managed pressure drilling with subsea fluid handling1 Oct 2026US 2026/0298039 A1
- System and method for blockage removal, cleaning and monitoring pressures in subsea equipment30 Apr 2026US 2026/0117608 A1Petroleo Brasileiro S.A. - Petrobras
- Multi-mode pumped riser arrangement and methods13 Nov 2025US 2025/0347178 A1Enhanced Drilling AS
- Rotating and reciprocating swivel apparatus and method31 Jul 2025US 2025/0243727 A1Mako Rentals, Inc.
- Rotating and reciprocating swivel apparatus and method5 Jun 2025US 2025/0179880 A1Mako Rentals, Inc.
Most cited
By later US patents
- Method and apparatus for deepwater drilling283US 4,813,495 AConoco Inc. · 1989
- Subsea hydraulic choke193US 4,046,191 AExxon Production Research Company · 1977
- Drilling fluid bypass for marine riser193US 4,291,772 AStandard Oil Company (Indiana) · 1981
- Rotating subsea diverter162US 6,230,824 B1Hydril Company · 2001
- Marine riser well control method and apparatus160US 4,626,135 AHydril Company · 1986