Single cycle dart operated circulation sub
US7934559B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 2007 |
| Grant date | May 3, 2011 |
| Priority date | — |
| Expiry date | Nov 2, 2027 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B21/103
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A circulating sub is run in with the circulating port closed. A dart blocks a central passage and moves two concentric pistons in tandem to open the circulation port while retaining the dart. The outer piston shoulders out in the circulation port open position. A second dart lands on the first and with applied pressure moves the inner piston relative to the shouldered outer piston to close the circulation port and only then discharge both darts. Subs can be used in tandem as long as higher located subs accept larger darts than lower subs and preferably the two darts for each sub are the same size. The ejected darts can be used to pressure actuate a downhole tool like a packer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.