Well abandonment and slot recovery
US11840899B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 13, 2020 |
| Grant date | Dec 12, 2023 |
| Priority date | — |
| Expiry date | Nov 10, 2040 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B31/20
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method of recovering casing in a wellbore using a vibratory casing recovery bottom hole assembly. In a vibratory casing recovery bottom hole assembly having a casing spear, a flow modifier and one or more further elements including a shock sub. The flow modifier produces cyclic variations in fluid flow through the assembly at a first frequency and at least one of the elements is configured to have a natural or resonant frequency when vibrated to be near or at the first frequency. By tuning elements of the bottom hole assembly to be close or at the frequency of the output of the flow modifier, the dynamic amplification factor of the system is maximised and longer lengths of casing can be recovered. A method of recovering casing using the vibratory casing recovery bottom hole assembly is also described. Further embodiments include a casing cutter and a hydraulic jack.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.