This study aims to develop a real-time drilling anomaly detection framework by combining unsupervised
machine learning methods with a rule-based approach. The primary objectives are to determine the most
effective and efficient machine learning model for real-time anomaly detection, develop feature engineering
as model inputs, identify early signs of drilling anomalies, and validate detection results by comparing them
against historical data and field reports.
The case study was conducted on three wells in South Sumatra, Indonesia (Well A, Well B, and Well C)
using historical drilling parameter data simulated as if it were streaming in real-time. Well A was focused
on kick detection validation, Well B on lost circulation, and Well C on stuck pipe, while bit balling cases
were validated using the Drilling Anomaly Index (DAI) and lithology due to the absence of specific incident
records. Data pre-processing included separating data by drilling section and handling missing values, while
model preparation involved tuning the Isolation Forest algorithm hyperparameters and determining the
severity threshold to balance sensitivity and noise tolerance.
The results indicate that the developed framework can detect anomalies earlier than conventional
observations recorded in the Daily Drilling Report (DDR) or Final Well Report (FWR) and can identify
early signs such as kick potential, lost circulation potential, differential sticking, and mechanical sticking.
Validation using the DAI demonstrated consistent detection of abnormal drilling behaviors across the wells.
Integration with a rule-based system also enhanced decision support capabilities by providing
recommended actions before anomalies escalate.
This study emphasizes the importance of high-quality real-time drilling parameter data for prediction
accuracy and operational safety. The developed framework provides a robust platform for proactive drilling
anomaly management, with potential for further development in non-rotary operations and expanded rulebased
determination. Overall, the combination of feature engineering, unsupervised learning, and a rulebased
system proved effective in improving safety, efficiency, and decision-making in drilling operations.
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