Method and apparatus to assess the thermal damage caused to a PCD cutter using capacitance spectroscopy

摘要

A method and apparatus for non-destructively determining the wear resistance of an ultra-hard polycrystalline structure after being coupled to a downhole tool using capacitance measurements. The apparatus includes a capacitance measuring device having a positive and negative terminal, a leached component comprising a polycrystalline structure that has been coupled to a downhole tool, a first wire, and a second wire. The first wire electrically couples the positive terminal to a surface of the leached component and the second wire electrically couples the negative terminal to a surface of the downhole tool. The capacitance is measured for the leached component one or more times and compared to a calibration curve that shows a relationship between capacitance values and wear resistance, thereby allowing determination of an estimated wear resistance for the polycrystalline structure.

主权项

1. A method of determining wear resistance of a downhole tool, comprising:
measuring capacitance values of a first plurality of leached polycrystalline diamond compact (PDC) cutters; destructively testing wear resistance of each cutter of the first plurality to obtain calibration data; brazing a second plurality of leached PDC cutters to the downhole tool, the first plurality and the second plurality being of the same type; after brazing, measuring a capacitance value of each cutter of the second plurality; and determining an estimated wear resistance of each cutter of the second plurality using the respective measured capacitance value of each cutter of the second plurality and the calibration data, wherein:
multiple capacitance values are measured for each cutter of the second plurality at different frequencies,the method further comprises selecting a minimum capacitance value for each cutter of the second plurality, andthe minimum value is used to determine the estimated wear resistance of each cutter of the second plurality.