Azimuth Estimation Using Survey Magnetometer Data
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Solution Overview
Problem
Magnetic measurements during wellbore drilling are affected by external interferences such as ferromagnetic materials and drilling fluids, leading to inaccuracies in azimuth estimation due to interference with the earth's magnetic field.
Innovation Solution
The method involves using locally computed tool-face and magnetic field information from survey-grade magnetometers to estimate azimuth, independent of the local magnetic field, by calculating the axial component of the magnetic field based on gravitational and magnetic data obtained during a stationary survey, and updating the magnetic field vector periodically to mitigate noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetometers are used to measure azimuth during wellbore drilling, then azimuth information can be obtained, but measurement precision deteriorates due to magnetic field interferences from ferromagnetic materials and drilling fluids
Solution Approach 1:
The patent extracts and removes the harmful magnetic interference components from the measured magnetic field vector. By identifying and eliminating the portions of the magnetic field caused by ferromagnetic materials and drilling fluids, the system recovers the true earth's magnetic field information needed for accurate azimuth calculation.
Solution Approach 2:
The patent introduces an intermediary computational process that processes the raw magnetic field measurements. This intermediary system uses gravitational field data and magnetic field vector analysis to compute the axial component and estimate azimuth, acting as a mediator between the corrupted measurements and the final azimuth value.
2Reliability
If conventional azimuth estimation methods are used, then azimuth can be calculated from magnetic field data, but reliability decreases in noisy environments with magnetic interferences
Solution Approach 1:
The patent converts the harmful magnetic interference into a beneficial estimation process. By analyzing the magnetic field vector components and using the relationship between gravitational and magnetic fields, the system transforms the corrupted measurements into reliable azimuth estimates through computational estimation of the axial magnetic field component.
Solution Approach 2:
The patent implements a feedback mechanism where the estimated axial magnetic field component is used to refine the azimuth calculation. The system continuously updates the magnetic field vector periodically, using the estimated values to correct and improve subsequent azimuth measurements, thereby enhancing reliability in noisy environments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces azimuth estimation errors, achieving a root-mean-square error of 0.01° in noiseless conditions and outperforming conventional methods in noisy environments, with improved accuracy and position control during drilling.
Implementation Method 1
Magnetic measurements obtained during wellbore drilling may be affected by external interferences
Implementation Method 2
gravitational field data using a gravimeter and magnetic field data using a magnetometer
Data Source
AI summary
A method may comprise measuring during a survey operation a gravitational field data using a survey accelerometer and magnetic field data using a survey magnetometer and determining during a drilling operation an azimuth of a wellbore based on the gravitational field data and the magnetic field data obtained during the survey operation. A system may comprise a drilling rig; a pipe string attached to the drilling rig; a bottom hole assembly attached to the pipe string, wherein the bottom hole assembly comprises at least one sensor; a drill bit, wherein the at least one sensor measure a revolutions-per-minute (RPM) of the drill bit; and a computing subsystem.