E21B 33/165
Cementing plugs specially adapted for being released down-hole
Official title: {Cementing plugs specially adapted for being released down-hole (cementing heads E21B33/05)}
E21B33/165 (Cementing plugs specially adapted for being released down-hole) appears on 243 US grants and 181 published applications in this corpus.
Search patents in E21B- Granted patents
- 243
- Published applications
- 181
- Assignees
- 53
- Inventors
- 313
- Latest grant
- 25 Aug 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 3 | 0 |
| 1978 | 1 | 0 |
| 1979 | 2 | 0 |
| 1980 | 1 | 0 |
| 1981 | 0 | 0 |
| 1982 | 1 | 0 |
| 1983 | 2 | 0 |
| 1984 | 2 | 0 |
| 1985 | 0 | 0 |
| 1986 | 2 | 0 |
| 1987 | 3 | 0 |
| 1988 | 1 | 0 |
| 1989 | 3 | 0 |
| 1990 | 4 | 0 |
| 1991 | 4 | 0 |
| 1992 | 2 | 0 |
| 1993 | 0 | 0 |
| 1994 | 1 | 0 |
| 1995 | 2 | 0 |
| 1996 | 2 | 0 |
| 1997 | 0 | 0 |
| 1998 | 9 | 0 |
| 1999 | 6 | 0 |
| 2000 | 3 | 0 |
| 2001 | 4 | 1 |
| 2002 | 8 | 11 |
| 2003 | 6 | 10 |
| 2004 | 12 | 10 |
| 2005 | 7 | 5 |
| 2006 | 5 | 1 |
| 2007 | 4 | 4 |
| 2008 | 2 | 7 |
| 2009 | 4 | 3 |
| 2010 | 5 | 4 |
| 2011 | 1 | 8 |
| 2012 | 7 | 7 |
| 2013 | 2 | 5 |
| 2014 | 7 | 5 |
| 2015 | 6 | 9 |
| 2016 | 8 | 7 |
| 2017 | 6 | 5 |
| 2018 | 7 | 13 |
| 2019 | 15 | 8 |
| 2020 | 6 | 4 |
| 2021 | 12 | 15 |
| 2022 | 9 | 8 |
| 2023 | 11 | 14 |
| 2024 | 16 | 9 |
| 2025 | 14 | 7 |
| 2026 | 4 | 1 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Sub-surface release plug with pressure bypass25 Aug 2026US 12,716,323 B2Weatherford Technology Holdings, LLC
- Methods for determining a position of a droppable object in a wellbore27 Jan 2026US 12,534,999 B2Schlumberger Technology Corporation
- Cement plug and methods of use6 Jan 2026US 12,516,584 B2Canadian Casing Accessories, Inc.
- Cement head flow diverter for tethered cement plug deployment6 Jan 2026US 12,516,586 B2Halliburton Energy Services.Inc.
- Detection of top of cement within an annular environment30 Dec 2025US 12,509,982 B2Expro Americas, LLC
- Sub-surface release plug with pressure bypass18 Jun 2026US 2026/0168349 A1Weatherford Technology Holdings, LLC
- Detection of top of cement within an annular environment2 Oct 2025US 2025/0305407 A1Expro Americas, LLC
- Cement head flow diverter for tethered cement plug deployment4 Sep 2025US 2025/0277425 A1Halliburton Energy Services.Inc.
- Non-reactive colloid particles to stop gas migration in expandable metal applications4 Sep 2025US 2025/0277426 A1Halliburton Energy Services.Inc.
- Composite Cement Retainer17 Jul 2025US 2025/0230726 A1
Most cited
By later US patents
- Downhole surge pressure reduction system and method of use340US 5,960,881 AJerry P. Allamon · 1999
- Procedures and equipment for profiling and jointing of pipes319US 6,457,532 B1Weatherford/Lamb, Inc. · 2002
- Method and apparatus for drilling and lining a wellbore236US 6,543,552 B1Weatherford/Lamb, Inc. · 2003
- Hydraulically actuated liner hanger arrangement and method215US 5,318,131 A1994
- Apparatus and method for isolating a section of tubing171US 6,527,049 B2Weatherford/Lamb, Inc. · 2003