Sleeve strain monitoring method and device based on axially arranged optical fibers

Abstract

The embodiment of the invention discloses a sleeve strain monitoring method and system based on axially arranged optical fibers, and the method comprises the steps: S1, arranging a distributed opticalfiber sensor on the surface of a to-be-measured sleeve in the axial direction of the to-be-measured sleeve, so as to obtain optical fiber strain data collected when a load is applied to the sleeve; S2, converting the optical fiber strain data acquired by the distributed optical fiber sensor into strain; and S3, based on a preset sleeve strain monitoring model, calculating load data correspondingto the strain. Real-time optical fiber strain is detected through a distributed optical fiber sensor. Meanwhile, the applied axial tensile load value and radial bending load value are recorded, load data corresponding to the output value of the distributed optical fiber sensor are obtained based on a casing pipe strain monitoring model, and the sleeve strain monitoring model can express the corresponding relation between the output value of the sensor and the sleeve load capacity (the axial direction and the radial direction). According to the invention, the deformation and load of the sleevecan be conveniently and accurately monitored.

Description

technical field [0001] The invention relates to the technical field of casing deformation monitoring, in particular to a method and device for casing strain monitoring based on axially arranged optical fibers. Background technique [0002] In the field of oil exploitation, it often happens that oil well casings are damaged in pieces. Typically, mining conditions are adjusted according to the damage to avoid magnification of the problem. For damaged cased wells, they can only be repaired, and those that cannot be repaired can only be scrapped, and the annual loss is huge. [0003] In recent years, a number of research teams have made beneficial attempts to monitor casing damage using optical fiber strain sensing technology, conducted laboratory and field tests, obtained effective monitoring data, and published relevant academic papers; the usual practice is: use FRP strengthened fiber optic cables are arranged axially for tension and compression sensing, and multiple fiber ...

AI Technical Summary

Problems solved by technology

However, the disadvantage of this method is that if it is necessary to accurately monitor the casing deformation in the full well depth range, a large number of cross-sectional lateral sensors need to be arranged, which will cause engineering construction pressure and cost pressure will be unimaginable

[0004] In summary, there are the following disadvantages in the existing casing damage monitoring technology: 1. The corresponding engineering construction process is complicated; 2. It can only monitor the situation of fortified sections. In practical applications, only key sections can be set and fortified sections The probability of being in the extreme area of ​​strain is low, and it is difficult to grasp the maximum area

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