E21B 33/146
Stage cementing, i.e. discharging cement from casing at different levels
Official title: {Stage cementing, i.e. discharging cement from casing at different levels}
E21B33/146 (Stage cementing, i.e. discharging cement from casing at different levels) appears on 194 US grants and 157 published applications in this corpus.
Search patents in E21B- Granted patents
- 194
- Published applications
- 157
- Assignees
- 72
- Inventors
- 304
- Latest grant
- 8 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 2 | 0 |
| 1977 | 0 | 0 |
| 1978 | 2 | 0 |
| 1979 | 0 | 0 |
| 1980 | 0 | 0 |
| 1981 | 3 | 0 |
| 1982 | 3 | 0 |
| 1983 | 1 | 0 |
| 1984 | 3 | 0 |
| 1985 | 0 | 0 |
| 1986 | 0 | 0 |
| 1987 | 1 | 0 |
| 1988 | 0 | 0 |
| 1989 | 2 | 0 |
| 1990 | 1 | 0 |
| 1991 | 3 | 0 |
| 1992 | 2 | 0 |
| 1993 | 0 | 0 |
| 1994 | 8 | 0 |
| 1995 | 3 | 0 |
| 1996 | 1 | 0 |
| 1997 | 1 | 0 |
| 1998 | 3 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 1 | 0 |
| 2002 | 1 | 2 |
| 2003 | 4 | 2 |
| 2004 | 4 | 3 |
| 2005 | 2 | 2 |
| 2006 | 3 | 2 |
| 2007 | 2 | 1 |
| 2008 | 0 | 1 |
| 2009 | 0 | 2 |
| 2010 | 2 | 5 |
| 2011 | 0 | 3 |
| 2012 | 3 | 6 |
| 2013 | 2 | 4 |
| 2014 | 6 | 5 |
| 2015 | 7 | 12 |
| 2016 | 3 | 9 |
| 2017 | 10 | 8 |
| 2018 | 10 | 16 |
| 2019 | 11 | 12 |
| 2020 | 16 | 15 |
| 2021 | 18 | 8 |
| 2022 | 11 | 12 |
| 2023 | 13 | 12 |
| 2024 | 15 | 8 |
| 2025 | 5 | 5 |
| 2026 | 6 | 2 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Cement system for CO2 injection and sequestration in mafic/ultramafic rock and method of use8 Sep 2026US 12,729,607 B2Protostar Group Ltd.
- Stage collar and related methods for operation14 Jul 2026US 12,680,418 B1Forum US, Inc.
- Drillable seat for multi-stage tools16 Jun 2026US 12,655,709 B1Halliburton Energy Services.Inc.
- Single sleeve downhole tool with detent pins for shifting7 Apr 2026US 12,595,716 B1Halliburton Energy Services.Inc.
- Stage tool assembly with control line protector and method of cementing a wellbore24 Mar 2026US 12,584,359 B2Forum US, Inc.
- Low profile stage collar and related methods for stage cementing operations8 Oct 2026US 2026/0309001 A1
- Stage tool assembly with control line protector and method of cementing a wellbore18 Jun 2026US 2026/0168334 A1Forum US, Inc.
- Cement system for co2 injection and sequestration in mafic/ultramafic rock and method of use6 Nov 2025US 2025/0341151 A1Protostar Group Ltd.
- Downhole fluid loss repair25 Sep 2025US 2025/0297527 A1Saudi Arabian Oil Company
- Cementing stage tool and associated methods28 Aug 2025US 2025/0270894 A1
Most cited
By later US patents
- Technique and apparatus for selective multi-zone vertical and/or horizontal completions239US 5,337,808 ANatural Reserves Group, Inc. · 1994
- Multiple stage cementing tool with inflation packer and methods of use170US 3,948,322 AHalliburton Company · 1976
- Stage cementing apparatus148US 4,669,541 ADowell Schlumberger Incorporated · 1987
- Gravel pack liner assembly and selective opening sleeve positioner assembly for use therewith121US 4,105,069 AHalliburton Company · 1978
- Apparatus and methods for separating and joining tubulars in a wellbore121US 6,598,678 B1Weatherford/Lamb, Inc. · 2003