Method and apparatus for well cementing through a tubular member
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 lower pilot sleeve valve to open the radial cementing passages in the mandrel and then shifts the inner valve unit to open the cementing ports in the tubular extension. The second stage of cementing can then be accomplished by cement introduced through the tubular member and passing outwardly through the mandrel passages and the radial cement ports. A plug is pumped down the tubular member into engagement with the upper pilot sleeve valve. Increased fluid pressure shifts the upper pilot sleeve valve to expose a passage in the mandrel and provide flow to a chamber surrounding a surface on the second outer valve unit. Increased fluid pressure in the bore of the tubular member will then produce a shifting of the second outer valve unit to seal the cement ports.
- Assignee:
- Baker Oil Tools Inc.
- Patent Number(s):
- US 4450912
- OSTI ID:
- 6354795
- Resource Relation:
- Patent File Date: Filed date 7 Jun 1982; Other Information: PAT-APPL-385616
- Country of Publication:
- United States
- Language:
- English
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