Bit life enhancement technology for wireline coring in granite-hosted uranium deposits based on multi-factor optimization

Abstract:

To address the problems of rapid diamond bit wear， frequent premature failure， and excessive bit replacements during wire-line coring drilling in granite-hosted uranium deposits， a comprehensive analysis was conducted using construction data from 12 boreholes in the Zhuguangnan ore concentration area together with laboratory measurements of rock drillability， indentation hardness， compressive strength， abrasion resistance， and chemical composition. The analysis covered bit wear morphology， lithology of intersected intervals， drilling parameters， flushing fluid conditions， and on-site operational records. A set of technical measures was developed， including lithology-adapted bit selection， controlled windows of weight-on-bit， rotary speed， and pump rate， cooling and chip-carrying capacity of the flushing fluid enhancement， initial run-in treatment for new bits， and low-disturbance drilling through fractured zones. Field application results show that the average rate of penetration increased from 2.02 m/h to 2.61 m/h， the average footage per bit rose from 91.2 m to 109.2 m， and the abnormal bit failure rate decreased from 32.7% to 14.3%.