Adaptive Wellbore Survey Quality Control with Error Ellipsoids
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Solution Overview
Problem
Conventional quality control methods for wellbore drilling rely on uncorrelated measurement thresholds and fail to account for various internal and external factors that affect the accuracy of well trajectory determination, leading to potential errors in the well placement process.
Innovation Solution
A system and method for adaptive quality control that utilizes a processor to receive surveys from a measurement-while-drilling tool, calculate error ellipsoids based on gravity and magnetic field measurements, and compare these surveys against error bounds to determine their acceptability, generating indications to stop or continue drilling when surveys fail quality control criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional quality control methods with uncorrelated measurement thresholds are used, then the quality control process is simple, but the accuracy of well trajectory determination deteriorates due to failure to account for internal and external factors
Solution Approach 1:
The patent implements dynamic quality control by continuously updating the error ellipsoid parameters as new survey data becomes available during drilling operations. The system adapts the acceptance criteria in real-time based on the accumulated statistical information from multiple surveys, rather than using fixed static thresholds. This dynamic approach improves measurement precision while managing complexity through automated adaptation.
Solution Approach 2:
The system employs feedback mechanisms by comparing each new survey's residual values against the error ellipsoid derived from previous surveys. The quality control process uses the statistical feedback from historical data to adjust and refine the acceptance criteria for current measurements. This feedback loop enables the system to account for internal and external factors affecting measurement accuracy without requiring overly complex manual intervention.
2Adaptability or versatility
If static quality control thresholds are used, then the quality control process is straightforward, but the system cannot adapt to changing drilling conditions and measurement quality
Solution Approach 1:
The patent transforms static quality control thresholds into dynamic, adaptive parameters. The error ellipsoid characteristics (size, shape, orientation) are continuously updated based on the statistical analysis of multiple surveys under varying drilling conditions. This allows the system to automatically adapt to changing measurement quality and drilling conditions without requiring complex manual reconfiguration of thresholds.
Solution Approach 2:
The quality control system performs self-adjustment by automatically updating its acceptance criteria based on the statistical properties of the incoming survey data. The error ellipsoid parameters are recalculated autonomously as new data becomes available, enabling the system to self-adapt to changing conditions without external intervention. This self-service capability improves adaptability while keeping the operational interface relatively simple.
Data Source
AI summary
A method of validating a directional survey includes measuring the gravity and magnetic field vectors using a surveying tool and computing an overall statistical distance of the measurement. The statistical distance may be calculated from reference values associated with the surveying tool using corresponding surveying tool codes with error values. In a further aspect, an error covariance matrix may be used to determine whether the new errors in a survey are consistent or not with errors from one or more previous surveys.