Method and apparatus for well cementing through a tubular member
US4450912A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1982 |
| Grant date | May 29, 1984 |
| Priority date | — |
| Expiry date | Jun 7, 2002 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B33/146
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
This invention provides a method and apparatus for effecting two stage cementing of well conduits by supplying cement through a tubular member. The apparatus involved provides a tubular conduit extension attachable to the bottom end of a well conduit and defines a cementing passage through its bottom end. Cementing ports are provided in the extension at a distance above its bottom end. A pair of concentrically adjacent valve units are communicable with the extension with the inner valve unit positioned in a closed position relative to the cement ports. The inner valve unit defines a seal bore which receives a mandrel which is secured to the tubular member. The mandrel incorporates two pilot sleeve valves which are positioned in closing relationship to radial passages in the hollow mandrel and each of which defines an upwardly facing surface for reception of sealing balls or plugs. The first stage of the cementing is accomplished by flow of cement from the tubular member through the mandrel and the extension and out the bottom end thereof. A sealing ball or plug is then dropped through the tubular member into engagement with the lower pilot sleeve valve. Increased pressure urges the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.