Method for monitoring oil-gas pipeline in mining subsidence area

Abstract

The invention discloses a method for monitoring an oil-gas pipeline in a mining subsidence area based on a fiber grating sensing technology. The method comprises the following steps of: monitoring pipe body axial strain with a fiber grating strain sensor, monitoring pipe-soil relative replacement with a fiber grating displacement sensor, and monitoring soil body horizontal deformation with a fiber grating sensing network; demodulating and preprocessing signals acquired by the sensors, and transmitting the signals to a remote monitoring center; further analyzing and processing data in the monitoring center, and computing mining subsidence soil body horizontal deformation change, pipe body axial strain change and pipe-soil relative displacement change; judging the state stabilities of the pipe body strain change and the soil body strain change, and judging whether the data surpass threshold values; when three parameter values are smaller than respective threshold values, judging that the pipeline is in a safe state; and when the pipe body axial strain reaches 70 percent of a pipe body limit strain value, or a pipe-soil relative displacement value reaches a threshold value and keeps constant, or a soil body horizontal deformation curve changes suddenly, performing pipeline safety joint early-warning.

Description

Technical field [0001] The invention relates to a method for monitoring oil and gas pipelines in a mined-out collapse area based on optical fiber grating sensing technology, and relates to the technical fields of measuring stress and temperature, measuring similar linear dimensions and pipeline systems. Background technique [0002] The space formed after the underground mine is mined is called the mined-out area. After the underground mineral layer is mined, the upper rock layer loses support, the balance condition is destroyed, and then it bends and collapses, so that the surface sinks and deforms, causing the surface to collapse and form a depression. With the continuous expansion of the mined-out area, the recessed land continues to develop to form a mined-out subsidence area, which in turn causes harm to buildings (structures) on the ground or underground. Mined-out collapse disaster is one of the main forms of geological disasters that cause loss of human life and property...

AI Technical Summary

Problems solved by technology

[0018] Due to these advantages, in the field of geotechnical engineering, fiber grating sensors are easy to embed in rock and soil for high-resolution and wide-range measurement of internal strain and temperature. The technical advantages are very obvious, especially in the ability to obtain long-term, Reliable deformation data of rock and soil. Currently, there is no report on the joint monitoring of fiber grating sensing technology used in goaf pipe body strain, pipe-soil relative displacement, and gob laying belt soil horizontal deformation.

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