High-sensitivity distributed pipelines infrastructure monitoring with internal deployed fibers and Rayleigh enhancement

Pipeline infrastructure monitoring based on distributed fiber-optic acoustic sensing is gaining significant attention aimed at real-time rapid detection of leakages, third-party intrusion, geo-hazards, corrosion, and other structural damages. Typical fibers installations are external to a pipeline, however retrofitting of existing pipelines through internal installation is desirable despite deployment challenges. Highly sensitive distributed acoustic sensing integrated within new pipelines or retrofit in existing pipelines can enable early detection of damage and degradation. In this work, we demonstrate pipeline integrity monitoring using distributed acoustic sensing and the Rayleigh backscattering-enhanced optical fibers deployed internal to the pipeline for high sensitivity detection of acoustic events. More specifically, traditional and backscattering-enhanced optical fibers are interrogated using bench-top phase-sensitive optical time-domain reflectometry (Φ-OTDR). The distributed acoustic sensing characteristics of two types of backscattered-enhanced fibers, Type A and Type B, are experimentally investigated. Our measurement analysis shows that the SNR of the acoustic event detection enhances ~2-fold and ~3-fold using the Type A and Type B fiber, respectively than that of the traditional SMF for pipeline monitoring. The presented investigation is a first validation for in-pipe deployed distributed acoustic sensing with high SNR and provides useful insight for diverse pipeline monitoring applications in the oil and gas distribution industry.