Importance

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Abstract

A method and apparatus for use in the oil well industry for running in drilling/production liners and sub-sea casings down a borehole through drilling fluid on a drill pipe using a multifunction diverter tool with the benefits of surge pressure reduction are disclosed. In accordance with the present invention, a multi-function diverter tool includes a housing assembly with a set of flow holes formed therein and a sliding sleeve arranged within the housing assembly having two sets of flow ports formed therein at different axial locations along the sleeve. By aligning either set of flow ports of the sleeve with the flow holes of the housing, the tool is set in a 'surge pressure reduction' mode. By shifting, or axially indexing, the sleeve downward, the set of flow holes becomes blocked by the sleeve thus setting the tool in a 'circulation' or 'cementing' mode. This shifting or indexing is accomplished using an indexing mechanism. The multi-function diverter tool of the present invention can be shifted from a first 'surge pressure reduction' mode to a 'circulation mode,' from the 'circulation mode' to a second 'surge pressure reduction' mode, and finally from the second 'surge pressure reduction' mode to a 'cementing' mode. The indexing mechanism of the present invention includes a return spring and brake system which provides the tool with more reliable shifting functionality.

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First Claim