At-Bit Magnetic Azimuth Measurement for Horizontal Drilling
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Solution Overview
Problem
Conventional directional drilling techniques for horizontal boreholes suffer from significant lateral and radial errors due to imprecision in inclination and azimuth measurements, particularly when encountering obstacles or deviating from planned paths, leading to suboptimal borehole placement and increased risk of tortuous boreholes.
Innovation Solution
The implementation of an At-Bit Inclination and Azimuth (ABIA) tool, which includes magnetic and gravity direction sensors at the drill bit, allows for real-time measurement and calibration of drilling direction perturbations, enabling timely adjustments to maintain precise alignment with the planned path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional directional drilling techniques with steering tool sensors are used, then drilling can proceed with basic guidance, but lateral and radial errors accumulate significantly over distance
Solution Approach 1:
The patent replaces the mechanical integration method (accumulating measurements from discrete sensor stations) with an electromagnetic field-based direct measurement system. External magnetic field beacons and electromagnetic waves directly determine borehole location without mechanical integration, eliminating cumulative errors over long distances.
Solution Approach 2:
The patent introduces external magnetic field beacons as intermediaries between the drill bit and surface equipment. These beacons create electromagnetic fields that serve as reference markers, allowing direct determination of borehole position and orientation without relying on cumulative sensor data from multiple stations.
2Measurement precision
If magnetometers are used to determine azimuthal direction, then horizontal direction can be measured, but precision is reduced due to steel in drill string and environmental magnetic interference
Solution Approach 1:
The patent uses external magnetic field beacons as intermediaries to provide reference magnetic fields for azimuth determination. These beacons create known magnetic field patterns that allow the drill bit sensors to determine azimuth by comparing measured fields against the known beacon patterns, eliminating interference from drill string steel and environmental sources.
Solution Approach 2:
The patent applies preliminary calibration procedures that measure and compensate for magnetic interference from the drill string and environment before actual drilling. By characterizing the interference patterns in advance, the system can subtract or compensate for these harmful effects during azimuth measurements.
3Productivity
If steering tool measurements are taken at regularly spaced stations, then borehole coordinates can be computed, but cumulative errors in inclination and azimuth determinations lead to intolerable lateral errors
Solution Approach 1:
The patent replaces the mechanical station-by-station measurement and integration system with continuous electromagnetic field-based positioning. External beacons provide continuous reference fields that allow real-time determination of borehole position and orientation at any depth, eliminating the discrete station approach and its associated cumulative errors while maintaining high drilling productivity.
Solution Approach 2:
The patent enables continuous measurement and correction of borehole position and orientation throughout the drilling process, rather than discrete measurements at spaced intervals. The electromagnetic field system provides continuous positional data, allowing ongoing adjustments to maintain precision without interrupting the drilling operation.
4Ease of operation
If drill guidance is provided from sensors located behind the drill bit, then remote measurement is possible, but the quality of borehole production is greatly degraded due to delayed correction capability
Solution Approach 1:
The patent positions sensors at the drill bit itself, performing measurements at the exact location where drilling occurs. This preliminary positioning of measurement equipment at the critical point enables immediate detection and correction of directional deviations, eliminating the delayed correction problem associated with remote sensors located behind the drill bit.
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 solution significantly reduces lateral and radial errors, ensuring accurate borehole placement and preventing tortuous paths by providing immediate correction for drilling direction changes, thus enhancing the reliability and precision of horizontal directional drilling.
Implementation Method 1
a magnetometer measures the Earth's magnetic field vector
Implementation Method 2
a gravity direction sensor measures the gravity field vector
Data Source
AI summary
Measurement of the inclination and azimuthal direction of a borehole extending beneath an obstacle, such as a body of water, which utilizes magnetic and gravity sensors at the drill bit of a borehole being drilled. Embodiments of the present invention determine and remove remanent field components and the effects of ferromagnetic permeability prior to and during drilling of the borehole.