| 摘要 |
A downhole abrading tool has a body with a first end for connection to a drill string, a cutting end, an exterior surface, a drilling fluid passageway, a valve, and a chamber. Upon exposure of the chamber to a wellbore fluid pressure due to excessive wear on the cutting end, the valve opens. The opening of the valve permits drilling fluid to flow from the drilling fluid passageway, through the exterior surface and into the wellbore. The flow of drilling fluid through the exterior surface causes a pressure drop that is detected at the surface by an operator of the downhole abrading tool. The valve movement may also cause the release of taggants, or indicators, into the drilling fluid that may also be detected by the operator, either visually or with the aid of detection equipment. |
