Wear indication apparatus and method

Abstract

Apparatus and method for monitoring the wear of a downhole tool, and providing indication of the degree of wear to an operator at the well surface. A pressurized fluid path within the cutting element matrix can exhibit a pressure drop when wear of the matrix progresses into the fluid path, or rotating torque can exhibit a drop when wear of the matrix progresses to wear pads within the cutting element matrix. Other wear indicators can also be built into the cutting element matrix. Progression of wear down to the indicator can be directly measured at the well surface, or relayed to the surface via a downhole communication system.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application relies upon U.S. Provisional patent application No. 60 / 571,246, filed on May 13, 2004, and entitled “Wear Indication Apparatus and Method.”STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable BACKGROUND OF THE INVENTION [0003] 1. Field of the Invention [0004] This invention is in the field of methods and apparatus used to perform downhole work in a well bore with a tool having a working profile which wears away during use, such as a mill, cutter, or drill bit. [0005] 2. Background Art [0006] In the drilling, completion, and workover of oil and gas wells, it is common to perform work downhole in the well bore with a tool which has some sort of wearable working profile interfacing with a downhole structure. Examples would be milling a downhole metal object with a milling tool, performing a washover operation with a rotary shoe, cutting through a tubular with a cutting tool, or drilling thr...

AI Technical Summary

Benefits of technology

[0009] The present invention provides a wear indicator imbedded in the working profile at a depth protecting the wear indicator from contact with the downhole structure which is to be the target of the work performed by the working profile. As the work progresses, the working profile wears away until the wear indicator is exposed to contact with downhole structure, such as an object being milled or cut, or the formation being drilled. Upon exposure, the wear indicator changes some operating parameter related to the downhole tool, and this change in the operating parameter is detected by the operator or by a control system, definitively indicating a specific amount of wear of the working profile. Multiple wear indicators can be provided at multiple depths within the working profile, to provide definitive indications of progressive levels of wear of the working profile.

Problems solved by technology

During the performance of these operations, it is common for the working profile of the tool, such as the cutting elements mounted on its lower or outer face, to wear away.

As this wear progresses, the effectiveness of the tool decreases.

Unfortunately, it is difficult or even impossible for the well operator at the Earth's surface to know accurately when this given amount of wear has occurred.

None of these parameters provides a definitive indication that the wear in the working profile has progressed to a specific degree at which the operator desires to pull the tool.

Pulling a tool prematurely adds unnecessary trips out of the well, adding to rig time.

Pulling the tool too late gradually decreases the effectiveness of the downhole operation, also adding to rig time.

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