E21B 25/00
Apparatus for obtaining or removing undisturbed cores
Official title: Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors (core bits E21B10/02)
E21B25/00 (Apparatus for obtaining or removing undisturbed cores) appears on 813 US grants and 603 published applications in this corpus.
Search patents in E21B- Granted patents
- 813
- Published applications
- 603
- Assignees
- 372
- Inventors
- 1,472
- Latest grant
- 1 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 19 | 0 |
| 1977 | 4 | 0 |
| 1978 | 10 | 0 |
| 1979 | 4 | 0 |
| 1980 | 4 | 0 |
| 1981 | 11 | 0 |
| 1982 | 9 | 0 |
| 1983 | 6 | 0 |
| 1984 | 12 | 0 |
| 1985 | 17 | 0 |
| 1986 | 13 | 0 |
| 1987 | 14 | 0 |
| 1988 | 11 | 0 |
| 1989 | 15 | 0 |
| 1990 | 14 | 0 |
| 1991 | 15 | 0 |
| 1992 | 12 | 0 |
| 1993 | 14 | 0 |
| 1994 | 13 | 0 |
| 1995 | 13 | 0 |
| 1996 | 18 | 0 |
| 1997 | 8 | 0 |
| 1998 | 14 | 0 |
| 1999 | 17 | 0 |
| 2000 | 16 | 0 |
| 2001 | 7 | 2 |
| 2002 | 11 | 11 |
| 2003 | 11 | 11 |
| 2004 | 15 | 9 |
| 2005 | 4 | 9 |
| 2006 | 8 | 7 |
| 2007 | 10 | 6 |
| 2008 | 4 | 9 |
| 2009 | 2 | 20 |
| 2010 | 5 | 15 |
| 2011 | 13 | 22 |
| 2012 | 13 | 23 |
| 2013 | 10 | 26 |
| 2014 | 22 | 33 |
| 2015 | 19 | 43 |
| 2016 | 25 | 32 |
| 2017 | 29 | 28 |
| 2018 | 40 | 39 |
| 2019 | 32 | 37 |
| 2020 | 41 | 34 |
| 2021 | 34 | 35 |
| 2022 | 27 | 49 |
| 2023 | 40 | 33 |
| 2024 | 45 | 23 |
| 2025 | 24 | 25 |
| 2026 | 19 | 22 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
- E21B 25/02The core receiver being insertable into, or removable from, the borehole without216
- E21B 25/10Formed core retaining or severing means122
- E21B 25/005Above ground means for handling the core119
- E21B 25/08Coating, freezing, consolidating cores109
- E21B 25/16Apparatus for obtaining or removing undisturbed cores: for obtaining oriented cores72
- E21B 25/06The core receiver having a flexible liner or inflatable retaining means50
- E21B 25/18The core receiver being specially adapted for operation under water47
Recent patents
- Forward and reverse circulation assembly for core drilling tools and coring operation method utilizing the same1 Sep 2026US 12,723,477 B1Hunan University of Science and Technology
- Identifying unconformities in subsurface formations1 Sep 2026US 12,724,171 B2Saudi Arabian Oil Company
- Devices for marking a core sample25 Aug 2026US 12,716,309 B2Imdex Technologies Pty Ltd
- Method and system for enabling acquisition of borehole survey data and core orientation data18 Aug 2026US 12,709,955 B2Reflex Instruments Asia Pacific Pty Ltd
- System and method to accelerate core images acquisition and processing using machine learning18 Aug 2026US 12,710,414 B2Saudi Arabian Oil Company
- Pressure-preserved coring tool, use method, and reservoir analysis method17 Sep 2026US 2026/0275823 A1China National Petroleum Corporation
- Quick Release Inner Tube Connector for Core Retrieval10 Sep 2026US 2026/0266153 A1
- Techniques for predicting co2 saturation in formations based on nuclear magnetic resonance data3 Sep 2026US 2026/0259344 A1Schlumberger Technology Corporation
- Method And System For Analyzing The Elemental Content Of Drill Cores27 Aug 2026US 2026/0251577 A1Lumo Analytics Ltd
- Robust Downhole Pump Barrel20 Aug 2026US 2026/0243245 A1Q2 Artificial Lift Services LLC
Most cited
By later US patents
- Method and apparatus for horizontal drilling205US 5,148,875 ABaker Hughes Incorporated · 1992
- Method and apparatus for horizontal drilling159US 5,074,366 ABaker Hughes Incorporated · 1991
- Bit-stabilized combination coring and drilling system142US 5,568,838 ABaker Hughes Incorporated · 1996
- Coring device with an improved core sleeve and anti-gripping collar with a collective core catcher107US 4,566,545 ANorton Christensen, Inc. · 1986
- Drilling tool with retractable pilot drilling unit100US 5,038,873 ABaker Hughes Incorporated · 1991