Fiber Optic Rotary Joint for Continuous Wellbore Sensing
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Solution Overview
Problem
Existing fiber optic sensing technologies for wellbore parameter measurement, such as Raman and Rayleigh backscattering, face signal power loss and limited sensitivity, preventing the use of fiber optic rotary joints, which results in labor-intensive and time-consuming data acquisition, limited to stationary operations, and reduced temperature resolution and accuracy.
Innovation Solution
The implementation of a Brillouin optical time domain sensor system using a fiber optic rotary joint that maintains optical communication between the optical fiber and the interrogator, enabling continuous measurement of temperature and strain during reel rotation, with Brillouin backscattering providing stronger and more sensitive signals than Raman or Rayleigh scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Raman or Rayleigh backscattering is used for fiber optic sensing, then temperature and strain measurements can be obtained, but signal power loss occurs and temperature resolution and accuracy are reduced
Solution Approach 1:
The patent changes the scattering parameter from Raman or Rayleigh backscattering to Brillouin backscattering. Brillouin scattering provides stronger return signals with better sensitivity to both temperature and strain, thereby improving measurement precision while maintaining signal power levels suitable for long-distance fiber optic sensing through the rotary joint.
2Loss of energy
If a fiber optic rotary joint is bypassed in the system, then signal loss is reduced, but labor and time costs increase due to required physical connections
Solution Approach 1:
The patent introduces a fiber optic rotary joint as an intermediary component that maintains continuous optical communication between the interrogator and the optical fiber during reel rotation. This intermediary enables data acquisition during dynamic operations without requiring physical disconnections, thereby reducing both signal loss from repeated connections and time costs associated with LOTO procedures.
3Productivity
If physical connection between optical fiber and interrogator is made, then data acquisition is possible, but the system must be stationary and data cannot be collected during running operations
Solution Approach 1:
The patent transforms the system from a static connection configuration to a dynamic one by implementing a fiber optic rotary joint that accommodates reel rotation. This dynamic configuration maintains optical connectivity throughout the deployment and retrieval process, enabling continuous data acquisition during running operations and significantly improving system versatility and productivity.
4Productivity
If Raman or Rayleigh backscattering is used through a fiber optic rotary joint, then continuous monitoring during rotation is possible, but significant signal losses occur
Solution Approach 1:
The patent changes the scattering mechanism parameter from Raman or Rayleigh to Brillouin scattering. Brillouin backscattering produces significantly stronger return signals that can traverse the fiber optic rotary joint with sufficient power margin, enabling continuous monitoring during rotation while minimizing signal losses and maintaining measurement quality over extended fiber lengths.
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 allows for accurate and continuous monitoring of wellbore temperature and strain along extended optical fibers, even during deployment and retrieval, enhancing data acquisition efficiency and resolution without the need for frequent physical connections, thus overcoming the limitations of existing technologies.
Implementation Method 1
Brillouin backscattering providing stronger and more sensitive signals than Raman or Rayleigh scattering
Implementation Method 2
a fiber optic rotary joint that maintains optical communication between the optical fiber and the interrogator
Data Source
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AI summary
A system includes an optical fiber integrated into a conveyance subsystem that is positionable downhole in a wellbore. The system also includes a backscattering sensor system positionable to monitor temperature and optical fiber strain along the optical fiber using backscattered light signals received from the optical fiber. Further, the system includes a fiber optic rotary joint positionable to optically couple the optical fiber with the backscattering sensor system to provide an optical path for the backscattered light signals to reach the backscattering sensor system.