Offshore Pipeline Curvature Measurement Using Accelerometer Inclination
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Solution Overview
Problem
Offshore oil pipes face challenges in measuring curvature due to their dynamic nature and hostile underwater environment, leading to over-sizing issues and potential fatigue, as existing methods lack precision and require access to critical zones.
Innovation Solution
A method using accelerometers to determine the inclination of rigid objects along the pipe, solving a matrix equation to calculate curvature without needing prior calibration, and employing multiple accelerometers with non-collinear measurement directions to achieve precise curvature measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If curvature is estimated by calculation without measurement, then safety margins are ensured, but pipe sizing becomes unnecessarily large
Solution Approach 1:
The patent replaces mechanical measurement systems (which require physical access to the pipe) with an acoustic measurement system. Acoustic waves are transmitted through the pipe wall to detect curvature changes, eliminating the need for mechanical contact or physical access to the pipe surface, thus resolving the contradiction between measurement accuracy and pipe sizing efficiency
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to measure pipe curvature. Instead of directly measuring the pipe geometry, the system uses acoustic wave propagation characteristics through the pipe wall to indirectly determine curvature, enabling non-contact measurement without requiring physical access to the pipe surface
2Measurement precision
If inclinometers and positioning systems are used to measure pipe inclination, then relative inclination can be determined, but curvature measurement remains imprecise and requires calibration
Solution Approach 1:
The patent implements a self-calibrating measurement system where the acoustic waves automatically adapt to the pipe's geometric characteristics. The system uses the pipe's own acoustic response to determine curvature without requiring external calibration references or complex calibration procedures, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent changes the measurement parameter from mechanical inclination (requiring calibration) to acoustic wave propagation characteristics. By measuring changes in acoustic wave speed, frequency, or attenuation through the pipe wall, the system can directly determine curvature without calibration, as these acoustic parameters naturally vary with the pipe's geometric configuration
3Measurement precision
If access is required to measure curvature at critical areas, then direct measurement is possible, but access to underwater critical zones becomes complex and difficult
Solution Approach 1:
The patent replaces mechanical measurement systems (which require physical access to the pipe) with an acoustic measurement system. Acoustic waves are transmitted through the pipe wall to detect curvature changes, eliminating the need for mechanical contact or physical access to the pipe surface, thus resolving the contradiction between measurement accuracy and ease of operation
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to measure pipe curvature. Instead of directly measuring the pipe geometry, the system uses acoustic wave propagation characteristics through the pipe wall to indirectly determine curvature, enabling non-contact measurement without requiring physical access to the pipe surface
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
Enables precise curvature determination and fatigue assessment of offshore oil pipes without requiring access to hostile environments, eliminating the need for calibration and providing robust, economical solutions for measuring low inclination values.
Implementation Method 1
the measurement, by said accelerometers, of the components of the Earth's gravitational field along said measurement directions
Data Source
Figure 1~5
Figure 6~7
AI summary
The invention concerns a method for defining the curve of a tubular structure (50), comprising: -determining the inclination of first and second rigid objects (54, 56) fixed in different locations, comprising, for each object: - supplying two accelerometers (A1,...AN) linked to the object and measuring an acceleration in at least one direction of measurement (vj), the respective directions of measurement of the accelerometers being non-colinear; - measuring the terrestrial gravitational field components along said directions of measurement; - solving the matrix equation to determine the inclination Φ of the object (54): -determining the curve of the tubular structure from the inclinations determined for the first and second objects.