Downhole strain distribution monitoring system based on distributed optical fiber sensing and monitoring method

Abstract

The invention provides a downhole strain distribution monitoring system based on distributed optical fiber sensing and a monitoring method of the downhole strain distribution monitoring system based on distributed optical fiber sensing. Armored optical cables are bound to the outside of sleeves of vertical wells, inclined wells or horizontal wells and are permanently fixed with cementing cement, the armored optical cables are bound and fixed to the outside of a coiled tubing by a metal clip, a long-term strain monitoring and sensing unit for oil and gas production wells, water injection wellsand monitoring or observation wells is constructed, the long-term strain monitoring and sensing unit and a distributed strain sensing and distributed temperature sensing (DSS/DTS) composite modulationand demodulation instrument near a wellhead together form the downhole strain distribution change dynamic monitoring system based on distributed optical fiber sensing and the monitoring method, the long-term stable, safe and reliable work of the oil and gas production wells, the water injection wells and the monitoring or observation wells can be effectively ensured, and the indispensable means,system and method are provided for scientific management of oil and gas reservoirs and enhanced recovery efficiency.

Description

technical field [0001] The invention belongs to the technical field of strain measurement, and in particular relates to an underground strain distribution monitoring system and a monitoring method based on distributed optical fiber sensing. Background technique [0002] Optical fiber sensing technology began in 1977 and developed rapidly with the development of optical fiber communication technology. Optical fiber sensing technology is an important symbol to measure the degree of informatization of a country. Optical fiber sensing technology has been widely used in military, national defense, aerospace, industrial and mining enterprises, energy and environmental protection, industrial control, medicine and health, metrology and testing, construction, household appliances and other fields, and has a broad market. There are hundreds of optical fiber sensing technologies in the world, and physical quantities such as temperature, pressure, flow, displacement, vibration, rotation...

AI Technical Summary

Problems solved by technology

Although the quasi-distributed optical fiber sensor represented by fiber Bragg grating (FBG) sensor can be used for strain measurement and real-time long-term monitoring of the downhole environment, however, the measuring point of the optical fiber Bragg grating sensor will be limited by the laser bandwidth. Limitations, not suitable for high-density or high spatial resolution multi-point strain measurement and real-time monitoring in deep wells and ultra-long horizontal wells

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