Time release downhole trigger
US7478678B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2005 |
| Grant date | Jan 20, 2009 |
| Priority date | — |
| Expiry date | Apr 20, 2026 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B23/042
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A setting mechanism is made to respond to hydrostatic pressure. Upon reaching a predetermined depth corresponding to a given pressure, a pilot piston is shifted to allow well fluids to bypass a first set of piston seals and reach a second set. A shear pin that held the pilot piston in position is broken as the hydrostatic pressure increases with greater depth attained. However, the shifting of the pilot piston does not cause the main piston in the assembly to set the downhole tool. The action of the well fluids on the secondary seal set on the pilot piston eventually fail the second seal set allowing hydrostatic pressure to bypass them and actuate the main piston that will set the downhole tool. Raising the tool from the wellbore allows the spring acting on the pilot piston to seal in a bore to isolate hydrostatic pressure from the operating piston.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.