Multi-function downhole tool

Abstract

A multi-function downhole apparatus is described which comprises a tubular main body having at least one recess formed in its outer surface. The recess is adapted to receive any of a set of interchangeable tool elements, which include stabiliser blades of different radial sizes, cleaning elements, roller reaming tool elements, a hole opener tool element, and a drilling casing shoe element. In particular, the apparatus allows drilling operations and wellbore cleaning operations to be carried out using the same tool body.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority to U.S. Provisional Patent Application No. 60 / 661,385, filed Mar. 14, 2005, which is incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to downhole tools used in wellbores, and, in particular, to downhole tools used in rotary operations. [0004] 2. Background of the Related Art [0005] A number of different types of downhole tools and equipment are used in the oil and gas exploration and production industry during the drilling of a wellbore, lining of the drilled bore with a metal casing / liner, and in the subsequent completion of the well to gain access to subterranean hydrocarbon bearing rock formations. [0006] These tools and equipment include, for example, drill strings used in the drilling of a wellbore; stabilisers and centralisers used for centralising equipment in a borehole or downhole tubing; reamers and other cutting t...

AI Technical Summary

Benefits of technology

[0029] The method allows the same tubular body to be configured as a cleaning tool, a stabiliser tool, or a roller reaming tool.

[0032] Preferably, the second set of recesses is rotationally offset with respect to the first set of recesses. In this way, the first and second set of recesses together provide an increased circumferential coverage of the tool elements when the tool is being run in the wellbore.

[0037] The method allows the same tubular body to be used as a stabiliser tool in wellbores, casings and linings of different inner diameter.

[0040] By inclining the attachment axis the need to provide a screw or bolt extending the entire depth of the removable tool element is avoided. In addition, the attachment axis can be aligned such that forces encountered during wellbore operations have an increased axial component.

Problems solved by technology

Changing out tools that have become worn or introducing new tools to the string to deal with unexpected problems can therefore result in a lengthy and costly operation.

Although prior art systems have addressed some important issues, problems persist with current equipment causing much downtime during drilling operations.

One particular such problem during rotary drilling is differential sticking of the pipe to the wellbore wall, which is particularly common when drilling through clay rich formations and when well pressure is greater than formation pressures.

Further, such formations cause ‘balling’, which is the effect of solids such as clays sticking to various tool components due to pressure effects.

These effects prevent the tools from operating properly and may drive the drill string to a halt.

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