Drillstring Orientation Measurement via Mechanical Linkage
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Solution Overview
Problem
Conventional drilling systems face inaccuracies in determining the toolface angle due to magnetic interference, vibrations, and centrifugal forces, which limit the accuracy of measurements in directional drilling, especially when using magnetic sensing devices.
Innovation Solution
An orientation measurement system is deployed in a wellbore drilling system with a processor, rotary position sensor, and orientation sensor, which determine the toolface angle relative to the borehole highside and transmit it continuously, allowing for accurate synchronization of measurements with the borehole highside and calculation of borehole azimuth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic sensing devices are used to determine toolface angle, then the measurement can be obtained, but the accuracy is degraded due to magnetic interference, vibrations, and centrifugal forces
Solution Approach 1:
The patent introduces an intermediary mechanical linkage system consisting of a non-rotating sleeve, rotating mandrel, and gear mechanism. This intermediary system transfers rotational motion from the rotating drill string to a stationary measurement platform, allowing accurate toolface angle measurement without direct exposure to magnetic interference and vibrations in the rotating section.
Solution Approach 2:
The patent replaces magnetic sensing devices with a mechanical measurement system using accelerometers and gear mechanisms. The accelerometers measure gravitational and centrifugal forces on a non-rotating platform, and the gear mechanism mechanically transfers rotational position data, eliminating the need for magnetic sensors that are susceptible to interference in the rotating environment.
2Measurement precision
If accelerometers are used to measure highside orientation, then direct measurement of orientation is achieved, but the measurement is degraded by shocks, vibrations, and centrifugal forces in the rotating system
Solution Approach 1:
The patent segments the measurement system into two distinct parts: a non-rotating measurement platform that remains stable and stationary relative to the borehole highside, and a rotating drill string section. This segmentation allows accelerometers to measure orientation accurately on the stable platform while the rotating section handles the dynamic drilling operations, preventing vibration and rotation-induced measurement errors.
Solution Approach 2:
The non-rotating sleeve acts as an intermediary platform that decouples the measurement function from the rotating drill string. It provides a stable reference frame for the accelerometers while allowing the rotating mandrel to transmit rotational position information through mechanical gears, thus protecting the measurement system from rotational disturbances.
3Productivity
If continuous measurement of borehole azimuth is performed, then real-time directional control is enabled, but the measurement accuracy is limited by difficulty in measuring transverse acceleration components
Solution Approach 1:
The patent replaces the traditional accelerometer-based measurement system with a mechanical gear mechanism that directly measures rotational position. The gear system mechanically couples the rotating mandrel to a stationary index, providing continuous and accurate azimuth measurement without relying on difficult-to-measure transverse acceleration components, thus achieving both continuous operation and high precision.
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 provides accurate and continuous orientation data, reducing errors caused by magnetic interference and vibrations, enabling precise directional control and measurement correlation during drilling.
Implementation Method 1
a rotary position sensor, which measures an angular position of the rotating section relative to the non-rotating section
Implementation Method 2
an orientation sensor, which determines the orientation of the non-rotating section relative to a reference frame such as borehole highside
Data Source
AI summary
An orientation measurement system is deployed in a wellbore drilling system having one or more reservoir imaging and characterization tools, directional tools, and/or other known BHA tools in a rotating section. The orientation measurement system includes a processor receiving signals from a rotary position sensor measuring an angular position of the rotating section relative to the non-rotating section and receiving signals from an orientation sensor determining the orientation of the non-rotating section relative to a reference frame such as highside. The processor uses the first and second signals to determine a tool face of the rotating member relative to the highside and periodically and/or continuously transmits the determined tool face along the BHA via a suitable communication link. The determined tool face is used by the BHA tools to synchronize measurements with highside and/or to determine azimuth.