A method and device for casing strain monitoring based on helically laid optical fibers

Abstract

The embodiment of the present invention discloses a casing strain monitoring method and device based on helically arranging optical fibers. The casing strain monitoring method includes: S1. Distributed optical fiber sensors are arranged in the form of wiring to obtain the optical fiber data collected when the casing is loaded; S2, convert the optical fiber data obtained by the distributed optical fiber sensors into corresponding strains through the strain interrogator; S3, based on The preset casing strain monitoring model calculates the load data corresponding to the strain, and the load data includes but not limited to tensile load, internal pressure load, and concentrated load. The invention can conveniently and accurately monitor the deformation and load of the casing.

Description

technical field [0001] The invention relates to the technical field of casing deformation monitoring, in particular to a casing strain monitoring method and device based on spirally laid 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 grating...

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 process of arranging the circumferential grating is complicated and cannot be arranged everywhere; 2. It can only monitor the situation of the fortification section, and in practical application it can only be used in key sections. The probability of setting and fortification section in the extreme value area of ​​strain is low, and it is difficult to grasp the maximum area situation

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