Updating the Dull Grading System

Abstract

Abstract The IADC standardized dull grading system was developed for both roller cone bits and fixed cutter bits in 1987 and last updated in 1992. In the meantime, fixed cutter bits have taken most of the market share from roller cone bits; drilling technologies, tools, and features changed significantly. The current IADC dull grading system is unable to capture new information and has issues with consistency, accuracy, and precision. A detailed analysis has been conducted using historically collected dull grading data that are available in the Ulterra database to understand the usefulness of the items in each column of the IADC dull grading system. The study surveyed people in different disciplines including sales, engineering, manufacturing, and marketing within the company to develop a novel updated dull grading system to make it useful across the board. The per-formance of the dull grading system is measured in terms of consistency, accuracy, precision, and compatibility with existing drill bits. The study evaluated and updated the structure (the way 8 columns are being divided), scal-ing 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 ob-solete or rarely used. The survey of the study is designed to assess the performance of the current system and compare it with the proposed system. The survey analysis results demonstrate that the proposed dull grading system is more user-friendly, consistent, accurate, and precise. The proposed dull grading system is developed focus-ing on fixed cutter bits as those hold over 90% of the market share. However, the grading system applies to roller cone bits and the hybrid of fixed and roller cone bits. A few worn fixed cutter bits are graded and shown as exam-ples using the proposed grading system. A novel updated dull grading system has been proposed, where the structure of the system, requested in-formation, and the method of data collection for a dull bit is updated. Considering the advancement of automation and digitization, digitizing the dull grading system would be the most useful goal. The proposed updated dull grading system would be a step towards digitization.