Gyro-Magnetic Wellbore Surveying Error Correction
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Solution Overview
Problem
Wellbore surveys face errors due to internal and external factors, such as gyroscopic sensor inaccuracies and external magnetic influences, leading to longer rig times and increased costs in well construction.
Innovation Solution
A method combining magnetic and gyroscopic survey data using statistical estimation processes like least squares or Kalman filtering to correct magnetic survey data, allowing for the use of magnetic-only surveys once error estimates converge, thereby reducing survey time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gyroscopic sensors are used for wellbore surveys, then measurement precision is improved, but loss of time increases due to longer survey duration
Solution Approach 1:
The patent combines magnetic survey data and gyroscopic survey data through a statistical estimation process (such as least squares or Kalman filtering) to create corrected magnetic survey data. This merging allows the system to achieve gyroscopic-level accuracy while maintaining the speed advantage of magnetic surveys, as magnetic surveys are faster but less accurate on their own.
Solution Approach 2:
The patent introduces an intermediary statistical estimation process that acts as a mediator between magnetic and gyroscopic survey systems. This intermediary process processes both data types to generate error estimates and corrected magnetic survey data, allowing the benefits of both systems to be realized without directly using the slower gyroscopic system for all measurements.
2Measurement precision
If gyroscopic survey data is processed continuously to maintain accuracy, then measurement precision is improved, but use of energy and device complexity increase
Solution Approach 1:
The patent implements a dynamic system where the processing of gyroscopic measurement data can be activated or deactivated based on convergence criteria. The statistical estimation process monitors error estimates and switches between processing modes, reducing computational complexity when full processing is not necessary while maintaining accuracy when needed.
Solution Approach 2:
The patent employs feedback mechanisms where error estimates are continuously monitored and used to determine when convergence has occurred. This feedback allows the system to adjust processing intensity, deactivating full gyroscopic data processing when error estimates indicate sufficient accuracy, thereby reducing computational complexity and energy consumption.
Data Source
AI summary
Various implementations described herein are directed to a method for surveying a wellbore. A statistical estimation process that combines magnetic survey measurement data and gyroscopic survey measurement data to form error estimates in a magnetic survey system is applied. The error estimates are used to correct magnetic survey data provided by the magnetic survey system. Magnetic only survey data is used when convergence of the error estimates has occurred. Information that facilitates drilling the wellbore is provided.