Fiber Optic Sensor Mounting for Drilling Pipe Pressure Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting pressure pulses in drilling fluid piping systems using strain gauges are challenging due to gradual dimensional changes, which are difficult to observe and quantify effectively.
Innovation Solution
The development of an optical sensor mounting system that uses a Sagnac Loop interferometer with a fiber optic sensing loop to measure expansion and contraction of piping by attaching optical sensors to the piping system, allowing for the detection of mechanical or thermal disturbances and vibrations through changes in pipe diameter caused by fluid pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauges are used to detect dimensional changes in piping, then measurement capability is provided, but measurement precision deteriorates due to gradual dimensional changes being difficult to observe and quantify
Solution Approach 1:
The patent replaces mechanical strain gauges with an optical sensing system (Sagnac interferometer with fiber optic cable) to detect dimensional changes. This substitution enables precise measurement of gradual pipe diameter changes by converting mechanical deformation into optical phase shifts, thereby resolving the measurement precision problem while maintaining ease of detection.
Solution Approach 2:
The patent changes the measurement parameter from direct mechanical strain measurement to optical path length measurement. By monitoring changes in the optical path length of the fiber optic cable as the pipe expands or contracts, the system achieves high precision in detecting gradual dimensional changes that were previously difficult to observe.
2Measurement precision
If optical sensors are attached to piping to measure expansion and contraction, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent designs a multi-functional mounting system that simultaneously serves as both the mechanical attachment structure and the optical sensor housing. The mounting system integrates functions of mechanical fixation, optical alignment, and environmental protection, thereby reducing overall device complexity while maintaining high measurement precision for pressure pulse detection.
Solution Approach 2:
The patent employs a nested structure where the fiber optic cable is positioned within a protective conduit that is itself mounted to the pipe. This nested arrangement consolidates multiple components into a compact integrated system, reducing spatial requirements and simplifying installation while preserving measurement precision.
3Reliability
If fiber optic sensing loop is used to detect pressure pulses, then reliability improves, but ease of operation deteriorates due to specialized installation requirements
Solution Approach 1:
The patent incorporates preliminary alignment features and pre-positioned mounting elements that guide the fiber optic cable installation. By preparing the mounting structure in advance with built-in alignment references and accessibility features, the system maintains high reliability for pressure pulse detection while significantly reducing installation complexity and improving ease of operation.
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
The system enables precise detection of downhole pressure pulses by processing changes in pipe diameter, preserving signal fidelity and rotational signal rejection, thus providing accurate data on fluid pressure within the piping system.
Implementation Method 1
The Sagnac interferometer operates by generating a light signal with a predetermined wavelength, transmitting the light signal through an optical fiber loop, and detecting the resulting coherent light phase shift
Implementation Method 2
detecting the resulting coherent light phase shift
Data Source
AI summary
The subject matter of this specification can be embodied in, among other things, a system for removably attaching an optical fiber sensor loop onto a tubular member, which includes an optical fiber sensor loop having a continuous optical fiber positioned arranged in a plurality of loops, each of said loops having a first end turn and a second end turn, a first and a second turn guide each including a plurality of turn grooves increasing outwardly in increasing radii, each of said turn grooves configured to receive an end turn portion of the optical fiber, a first and a second supporting wedge each having a planar first surface configured to receive a turn guide and a curved second surface configured to be received on the tubular member, and a connector configured to couple the first mounting wedge to the second mounting wedge.