Optical Fiber Cable Curvature for Seismic Coupling
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Solution Overview
Problem
Existing sensing systems, such as DAS, face challenges in ensuring effective coupling of optical fiber cables with the environment for accurate seismic data measurement in subterranean formations, leading to inefficient detection of seismic waves.
Innovation Solution
The proposed solution involves a sensing system with an optical fiber cable that achieves improved mechanical coupling by direct physical contact with the casing or formation, utilizing a deployment mechanism with a predetermined curvature and tension control to ensure the optical fiber cable is in contact with the borehole or casing, enhancing strain transfer and seismic wave detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical fiber cable is deployed without predetermined curvature and tension control, then the deployment process is simpler, but the coupling between the cable and the borehole environment is insufficient
Solution Approach 1:
The optical fiber cable is pre-configured with a predetermined curvature (such as a spiral or loop shape) before deployment. This preliminary geometric configuration enables the cable to naturally contact the borehole wall or casing upon deployment, ensuring effective strain coupling without requiring complex active control mechanisms during the deployment process.
Solution Approach 2:
The patent applies curvature to the optical fiber cable by pre-forming it into spiral or loop shapes. This curved configuration allows the cable to conform to the borehole geometry and maintain continuous contact with the borehole wall or casing, thereby improving seismic wave detection capability while keeping the deployment mechanism relatively simple.
2Measurement precision
If the optical fiber cable is maintained in a non-curvature shape with tension, then the cable remains straight and easy to deploy, but it does not contact the borehole wall for effective strain transfer
Solution Approach 1:
The deployment mechanism dynamically transitions the optical fiber cable from a straight, tensioned state during deployment to a curved, contact state upon installation. The pre-configured curvature is released as the cable is deployed, allowing it to naturally form spiral or loop shapes that contact the borehole wall, thus achieving both easy deployment and effective strain transfer.
Solution Approach 2:
The cable is pre-formed with a specific curvature configuration that is activated during deployment. This preliminary geometric preparation ensures that when the cable is deployed, it automatically transitions to a contact configuration with the borehole environment, eliminating the need for complex post-deployment adjustments.
3Reliability
If the optical fiber cable is released to form curvature, then it contacts the casing for improved coupling, but the deployment process becomes more complex
Solution Approach 1:
The optical fiber cable is pre-configured with a predetermined curvature (spiral or loop shape) and associated tensioning elements before deployment. This preliminary configuration allows the cable to automatically form the desired curved shape and contact the casing upon deployment, achieving reliable strain coupling without requiring complex active control mechanisms during the deployment process.
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 configuration significantly improves the responsiveness of the optical fiber cable to seismic waves, providing more accurate and reliable sensing measurements by ensuring direct contact and effective strain coupling, thereby enhancing the detection of seismic data in subterranean formations.
Implementation Method 1
ensuring good physical coupling between the optical fiber cable and the environment to be measured
Data Source
AI summary
A sensing system may comprise a deployment device having an optical fiber cable with a predetermined curvature or an intrinsic curvature. The sensing system may be deployed into a location that is remote or difficult to navigate, for example, a large vessel or a borehole of a well. A deployment device may deploy the optical fiber cable and a tension control tool may maintain the deployment device along with the optical fiber cable in a straight or non-curved shape until the optical fiber cable has reached a predetermined location or position. A force may then be applied to the optical fiber cable to cause a portion of the optical fiber cable to contact an interior wall of the area or location, for example, a borehole or the deployment device. Measurements may be retrieved from the optical fiber cable, for example, measurements used in distributed acoustic sensing in vertical seismic profiling.