E21B 21/16
Methods or apparatus for flushing boreholes: using gaseous fluids
Official title: using gaseous fluids (E21B21/14 takes precedence)
E21B21/16 (Methods or apparatus for flushing boreholes: using gaseous fluids) appears on 198 US grants and 120 published applications in this corpus.
Search patents in E21B- Granted patents
- 198
- Published applications
- 120
- Assignees
- 115
- Inventors
- 378
- Latest grant
- 18 Aug 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 7 | 0 |
| 1977 | 4 | 0 |
| 1978 | 5 | 0 |
| 1979 | 2 | 0 |
| 1980 | 3 | 0 |
| 1981 | 6 | 0 |
| 1982 | 3 | 0 |
| 1983 | 3 | 0 |
| 1984 | 2 | 0 |
| 1985 | 7 | 0 |
| 1986 | 0 | 0 |
| 1987 | 2 | 0 |
| 1988 | 1 | 0 |
| 1989 | 4 | 0 |
| 1990 | 3 | 0 |
| 1991 | 3 | 0 |
| 1992 | 2 | 0 |
| 1993 | 3 | 0 |
| 1994 | 1 | 0 |
| 1995 | 7 | 0 |
| 1996 | 5 | 0 |
| 1997 | 2 | 0 |
| 1998 | 3 | 0 |
| 1999 | 8 | 0 |
| 2000 | 3 | 0 |
| 2001 | 4 | 1 |
| 2002 | 3 | 3 |
| 2003 | 3 | 2 |
| 2004 | 6 | 8 |
| 2005 | 4 | 3 |
| 2006 | 4 | 3 |
| 2007 | 2 | 1 |
| 2008 | 2 | 2 |
| 2009 | 1 | 2 |
| 2010 | 2 | 6 |
| 2011 | 2 | 9 |
| 2012 | 6 | 6 |
| 2013 | 1 | 8 |
| 2014 | 9 | 9 |
| 2015 | 4 | 7 |
| 2016 | 10 | 5 |
| 2017 | 6 | 6 |
| 2018 | 8 | 7 |
| 2019 | 5 | 4 |
| 2020 | 4 | 7 |
| 2021 | 6 | 2 |
| 2022 | 3 | 2 |
| 2023 | 3 | 4 |
| 2024 | 5 | 8 |
| 2025 | 5 | 3 |
| 2026 | 1 | 2 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Mass flow for non-contact boring18 Aug 2026US 12,709,944 B2Phoenix Boring, Inc.
- Drill head for creating a borehole in the ground4 Nov 2025US 12,460,487 B2Herrenknecht AG
- Downhole method and associated apparatus27 May 2025US 12,312,912 B2Hydropulsion Limited
- Monobore drilling methods with managed pressure drilling20 May 2025US 12,305,456 B2Opla Energy Ltd.
- Full-hole reverse circulation cluster-type down-the-hole (DTH) hammer with multiple independent channels29 Apr 2025US 12,286,850 B2Haozhou Drilling Engineering Machinery (Shandong) Co., Ltd.
- Cleaning boreholes formed by millimeter wave drilling27 Aug 2026US 2026/0251017 A1Quaise Energy, Inc.
- Systems and methods for production of low carbon intensity hydrogen from geologic sources26 Feb 2026US 2026/0054982 A1Koloma, Inc.
- Mass Flow For Non-Contact Boring16 Oct 2025US 2025/0320782 A1Phoenix Boring, Inc.
- Surface waveguide16 Oct 2025US 2025/0321258 A1Quaise Energy, Inc.
- Systems, processes, and modeling methods for drilling in hot dry rock using supercritical or dense phase carbon dioxide27 Mar 2025US 2025/0102191 A1Blade Energy Partners Ltd.
Most cited
By later US patents
- Coalbed methane drilling359US 5,411,104 AConoco Inc. · 1995
- Continuous circulation apparatus for air drilling well bore operations118US 4,315,553 A1982
- Well drilling system with closed circulation of gas drilling fluid and fire suppression apparatus114US 5,890,549 A1999
- Method and apparatus for mud pulse telemetry in underbalanced drilling systems107US 6,097,310 ABaker Hughes Incorporated · 2000
- Coiled tubing drilling with supercritical carbon dioxide80US 6,347,675 B1Tempress Technologies, Inc. · 2002