E21B 21/14
Methods or apparatus for flushing boreholes: using liquids and gases
Official title: using liquids and gases, e.g. foams
E21B21/14 (Methods or apparatus for flushing boreholes: using liquids and gases) appears on 154 US grants and 86 published applications in this corpus.
Search patents in E21B- Granted patents
- 154
- Published applications
- 86
- Assignees
- 103
- Inventors
- 322
- Latest grant
- 14 Jul 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 1 | 0 |
| 1978 | 3 | 0 |
| 1979 | 2 | 0 |
| 1980 | 3 | 0 |
| 1981 | 2 | 0 |
| 1982 | 4 | 0 |
| 1983 | 2 | 0 |
| 1984 | 5 | 0 |
| 1985 | 4 | 0 |
| 1986 | 5 | 0 |
| 1987 | 2 | 0 |
| 1988 | 2 | 0 |
| 1989 | 1 | 0 |
| 1990 | 1 | 0 |
| 1991 | 3 | 0 |
| 1992 | 4 | 0 |
| 1993 | 3 | 0 |
| 1994 | 4 | 0 |
| 1995 | 7 | 0 |
| 1996 | 1 | 0 |
| 1997 | 1 | 0 |
| 1998 | 4 | 0 |
| 1999 | 5 | 0 |
| 2000 | 9 | 0 |
| 2001 | 2 | 3 |
| 2002 | 9 | 2 |
| 2003 | 1 | 1 |
| 2004 | 2 | 6 |
| 2005 | 0 | 3 |
| 2006 | 3 | 2 |
| 2007 | 5 | 3 |
| 2008 | 0 | 1 |
| 2009 | 0 | 5 |
| 2010 | 2 | 4 |
| 2011 | 1 | 2 |
| 2012 | 2 | 5 |
| 2013 | 3 | 2 |
| 2014 | 2 | 5 |
| 2015 | 7 | 5 |
| 2016 | 4 | 6 |
| 2017 | 3 | 2 |
| 2018 | 3 | 4 |
| 2019 | 3 | 5 |
| 2020 | 3 | 3 |
| 2021 | 5 | 0 |
| 2022 | 0 | 3 |
| 2023 | 5 | 4 |
| 2024 | 4 | 2 |
| 2025 | 4 | 7 |
| 2026 | 2 | 1 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Modular downhole tool systems with integrated hydraulic-electric actuation and intelligent flow control for coiled tubing operations14 Jul 2026US 12,680,387 B1Schlumberger Technology Corporation
- Drill string and components therefor7 Apr 2026US 12,595,710 B2Tri-Tube Drilling Systems Pty Ltd
- Method of underbalanced drilling using foaming agent30 Dec 2025US 12,509,952 B2King Fahd University of Petroleum and Minerals
- Ground drilling device11 Nov 2025US 12,467,320 B2
- Coal mining system and method of dual circulation drilling with mechanical reaming and abrasive jet24 Jun 2025US 12,338,721 B2China University of Mining and Technology, Beijing
- Chemical methods for cavitation inception in downhole environments25 Jun 2026US 2026/0176520 A1Aramco Innovations LLC
- Method of underbalanced drilling using foaming agent20 Nov 2025US 2025/0354444 A1King Fahd University of Petroleum and Minerals
- Re-start of well after a well kill operation11 Sep 2025US 2025/0283396 A1Saudi Arabian Oil Company
- Efficient swelling inhibitor for drilling foams31 Jul 2025US 2025/0243397 A1Fiamochem Inc.
- Drill string and components therefor17 Jul 2025US 2025/0230721 A1Tri-Tube Drilling Systems Pty Ltd
Most cited
By later US patents
- Coalbed methane drilling359US 5,411,104 AConoco Inc. · 1995
- Method and system for drilling and completing underbalanced multilateral wells utilizing a dual string technique in a live well205US 6,065,550 A2000
- Method and system for drilling underbalanced radial wells utilizing a dual string technique in a live well170US 5,720,356 A1998
- Process and apparatus for completing a well in an unconsolidated formation164US 5,255,741 AMobil Oil Corporation · 1993
- Apparatus and methods for stimulating a subterranean well156US 6,047,773 AHalliburton Energy Services.Inc. · 2000