• Updating the Dull Grading System 

    The IADC standardized dull grading system was developed for both roller cone bits and fixed cutter bits in 1987 and was last updated in 1992. Since then, fixed cutter bits have taken most of the market share from roller cone bits, and drilling technologies, tools, and features changed significantly.  

    A detailed analysis was conducted to understand the usefulness of the items in each column of the IADC dull grading system. The study surveyed people in different disciplines to develop a novel updated dull grading system; its performance is measured in terms of consistency, accuracy, precision, and compatibility with existing drill bits. The study evaluated and updated the structure, scaling of the worn cutters, and the items of the columns of the dull grading system. 

    The historic data analysis results showed that some of the items in the current dull grading system are obsolete or rarely used. The survey analysis results demonstrate that the proposed dull grading system is more user-friendly, consistent, accurate, and precise. A novel updated dull grading system has been proposed, including updates to the structure of the system, requested information, and the method of data collection.  

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    This presentation is from the 2022 IADC/SPE International Drilling Conference and Exhibition.   

    • Paper Number: SPE-208740-MS  
    • Published: 1 March 2022  
    • Authors: Mahabub Alam; Spencer Case; Junaid Hussain

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  • Updating the Dull Grading System 

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