E21B 21/082
Dual gradient systems, i.e. using two hydrostatic gradients or drilling fluid densities
Official title: {Dual gradient systems, i.e. using two hydrostatic gradients or drilling fluid densities}
E21B21/082 (Dual gradient systems, i.e. using two hydrostatic gradients or drilling fluid densities) appears on 66 US grants and 70 published applications in this corpus.
Search patents in E21B- Granted patents
- 66
- Published applications
- 70
- Assignees
- 37
- Inventors
- 161
- Latest grant
- 2 Jun 2026
Filings by year
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| 2011 | 4 | 7 |
| 2012 | 2 | 2 |
| 2013 | 6 | 6 |
| 2014 | 5 | 4 |
| 2015 | 1 | 2 |
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| 2017 | 3 | 6 |
| 2018 | 2 | 4 |
| 2019 | 2 | 5 |
| 2020 | 7 | 3 |
| 2021 | 4 | 3 |
| 2022 | 2 | 2 |
| 2023 | 4 | 4 |
| 2024 | 4 | 5 |
| 2025 | 5 | 2 |
| 2026 | 1 | 0 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
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- Multi-mode pumped riser arrangement and methods8 Jul 2025US 12,352,112 B2Enhanced Drilling AS
- Multi-mode pumped riser arrangement and methods8 Jul 2025US 12,352,113 B2Enhanced Drilling AS
- Monobore drilling methods with managed pressure drilling20 May 2025US 12,305,456 B2Opla Energy Ltd.
- Multi-mode pumped riser arrangement and methods28 Jan 2025US 12,209,461 B2Enhanced Drilling AS
- Multi-mode pumped riser arrangement and methods13 Nov 2025US 2025/0347178 A1Enhanced Drilling AS
- Methods of swabbing liquid loaded wells, and killing wells, with the use of compression pumps, regulators and filtration techniques9 Oct 2025US 2025/0314166 A1Zenrg Services, LLC
- Monobore drilling methods with managed pressure drilling17 Oct 2024US 2024/0344412 A1Opla Energy Ltd.
- Multi-mode pumped riser arrangement and methods4 Jul 2024US 2024/0218744 A1Enhanced Drilling AS
- Multi-mode pumped riser arrangement and methods4 Jul 2024US 2024/0218745 A1Enhanced Drilling AS
Most cited
By later US patents
- Rotating subsea diverter162US 6,230,824 B1Hydril Company · 2001
- Annulus pressure control drilling systems and methods79US 7,836,973 B2Weatherford/Lamb, Inc. · 2010
- System and method for treating drilling mud in oil and gas well drilling applications59US 6,926,101 B22005
- Method for installing a well casing into a subsea well being drilled with a dual density drilling system57US 6,328,107 B1ExxonMobil Upstream Research Company · 2001
- Multi-gradient drilling method and system54US 6,530,437 B2Maurer Technology Incorporated · 2003