Determining the fracture gradient (FG) is key to maintaining wellbore safety. A Leak-Off Test (LOT) helps calculate the fracture pressure, which is expressed as equivalent mud weight (EMW). Traditional EMW calculation methods are slow and error-prone. The paper, presented at the 17th OMC Med Energy Conference and Exhibition in Ravenna, introduces an automated system using real-time sensor data and decision tree algorithms to identify LOT phases and compute EMW accurately. The system reduces calculation time, improves accuracy, and provides secure, scalable solutions for better wellbore integrity.
Challenges in LOT interpretation
LOT interpretation is often done manually on-site, using selected pressure points and visual analysis in tools like Excel, which limits the dataset. While standard tests are straightforward, non-standard cases become more complex due to factors like gas, fractures, or borehole instability. These deviations require engineers to rely on subjective judgment, leading to inconsistencies and potential inaccuracies in defining the LOP and estimating the EMW.
Automated EMW Determination System
To improve LOT interpretation, a new automated workflow collects real-time test data and streamlines key steps, ensuring more accurate analysis. The system calculates EMW, classifies tests as standard or non-standard, and enhances data processing using decision tree algorithms. This reduces subjective interpretation and increases consistency. By automating the process, it improves drilling safety, efficiency, and decision-making. The workflow handles both standard and non-standard cases, ensuring reliable results through systematic classification and calculation.
End-to-End Workflow: From Data Validation to Automated Analysis
The LOT data processing workflow begins with data validation, ensuring files are correctly formatted and meet specifications. After validation, the system ingests the data, registers metadata, and links it to relevant personnel. On-site engineers then provide additional parameters like mud weight and well data. Automated analysis follows, where a decision tree identifies leak-off points, calculates EMW, and classifies the test as standard or non-standard. Final results are stored, and notifications are sent to key stakeholders. For non-standard cases, a secondary review ensures accurate interpretation before finalization.
User Interaction and Final Deliverables
The system’s final LOT results are accessible via a user-friendly web interface and a generated PDF report. Operators input well details, track analysis progress, and can make manual adjustments if needed. Once complete, the system delivers a PDF report with key results (LOP, EMW), test classification, and visual plots, along with a CSV file for detailed analysis. This combination of real-time tools, automated reporting, and user adjustments enhances decision-making and drilling efficiency.