Distributed fiber-optic sensing based oil-gas pipeline safety monitoring system and method

The invention discloses a distributed fiber-optic sensing based oil-gas pipeline safety monitoring system and method. The method includes the steps of 1, establishing a Michelson fiber-optic interferometer with a 3*3 fiber-optic coupler to obtain three interference signals of an oil-gas pipeline, with each two of the interference signals, having a fixed phase difference 2Pi/3; 2, demodulating the interference signals to obtain an interference optical phase Delta Phi(5t) caused by disturbance; 3, subjecting a formula of the interference optical phase Delta Phi(5t) to a sum-difference to product operation; 4, filtering a phase direct-current component and performing derivation by differentiation; 5, performing spectrum transformation; 6, calculating a disturbance position L2 of the oil-gas pipeline. The distributed fiber-optic sensing based oil-gas pipeline safety monitoring system and method has the advantages that complex and expensive hardware equipment is omitted, the diploma of sensitivity and trapped wave point aliasing in the white light interferometer positioning technology is also avoided, insertion loss is low, the system and the method are applicable to safety warning for long-distance wide-range oil and gas pipelines, an available monitoring range is up to 150km, and the system and the method have a promising application prospect.