Evaluation of Cuttings Flow and Early Warning Engineering Practices for Wellbore Stability

(1) Research Objectives and Scope: Real-time monitoring and early warning of wellbore instability during drilling operations are recognized as critical challenges in ensuring drilling safety. Severe gravitational settling of cuttings and drilling tool eccentricity frequently lead to cuttings bed formation, resulting in inadequate hole cleaning and wellbore instability. (2) Methodology, Procedures, and Processes: A comparative analysis between actual and theoretical cuttings flow rates reveals operational insights: an actual flow rate exceeding the theoretical value indicates effective disruption of pre-existing cuttings beds or potential wellbore spalling by current drilling parameters, while a lower actual rate signals insufficient hole cleaning. By calculating theoretical and actual cuttings volumes per meter of drilled depth, a real-time cuttings volume balance tracking method was developed to quantify retained cuttings volume and cuttings return rate. (3) Results, Observations, and Conclusions: Field trials of this methodology, integrated with cuttings weighing devices, were conducted in six shale gas wells in the Sichuan Basin. The implementation successfully ensured downhole safety, with post-drilling caliper logging data demonstrating an average consistency rate exceeding 80%, thereby validating the method’s reliability. (4) Innovations, Technical Contributions, and Significance: The real-time well logging-based monitoring of cuttings flow enables timely detection of dynamic cuttings return variations and precise identification of wellbore instability risks during drilling. The established digital tracking curves exhibit strong correlation with electrical logging data, providing quantitative geological evidence to support drilling engineering decisions. This approach represents a paradigm shift in proactive risk management and operational optimization for complex drilling environments.