Bit wear analysis and optimization for vibration assisted rotary drilling (VARD) using impregnated diamond bits

Abtahi, Alireza (2011) Bit wear analysis and optimization for vibration assisted rotary drilling (VARD) using impregnated diamond bits. Masters thesis, Memorial University of Newfoundland.

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The effect of vibrations on bit wear and the rate of penetration in rotary drilling was investigated. A laboratory scale drilling rig was used for experiments with capability of controlling important drilling factors such as WOB (Weight On Bit), flow rate, RPM, and vibration. Vibration under different amplitudes was studied using impregnated diamond coring bits. The main goal of this study is to find the optimum drilling conditions considering both ROP (Rate Of Penetration) and wear including the effect of vibration. -- Bit profile shape was found to be another important factor affecting ROP and bit wear. In all experiments, three main profile shapes appeared after some drilling in the sequence of: V-grooved, flat end, and rounded edge. The highest ROP results were obtained with V-grooved, decreasing in the order: unused, flat end, and rounded edge. Vibration had more effect on bit wear than profile shape. Profile shapes with sharper edges wore away rapidly -- Wear and bit profile changes should be taken into account in a study to relate ROP to WOE. Otherwise, the relationship observed between these variables may not be correct.

Item Type: Thesis (Masters)
Item ID: 9822
Additional Information: Includes bibliographical references (leaves 99-100)
Department(s): Engineering and Applied Science, Faculty of
Date: 2011
Date Type: Submission
Library of Congress Subject Heading: Drilling and boring; Bits (Drilling and boring); Diamond bits; Rotary percussion drills--Vibration; Mechanical wear

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