Abstract Distributed fiber optic sensing (DFOS), a rapidly evolving fiber-optic based technology for permanent well-based and geophysical monitoring for CO2 geological storage (CGS) has attracted more attentions to investigate in multiple scales. In this study, two field trial wells were drilled, one well with 300 m depth in Mobara and the other well with 880 m in Ichihara, Japan and DFOS cables were deployed behind well casings. High-pressure water jet tests are performed at constant location of 127 m depth and at changeable jet locations with 1.33 m/min and 0.51 m/min pulling speeds in the 300 m well. Then, this DFOS system was utilized to monitor the water jet along the entire length of the 880 m well with 1.2 m/min descending speed. The temperature profiles induced by water jet could be real-time monitored and analyzed the cementing quality to further evaluate the wellbore integrity. The results show that the temperature abnormal zones have a good reverence with poor cementing in the two wells, which compared well with geophysical well logging data. Therefore, permanently installed DFOS wells will enable an efficient and simpler tool to diagnose the wellbore integrity for the CGS monitoring projects via the field water jet tests.

中文翻译：

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用于实时监测水射流测试的光纤分布式传感技术：对井筒完整性诊断的影响

摘要 分布式光纤传感（DFOS）是一种快速发展的基于光纤的技术，用于二氧化碳地质储存（CGS）的永久性井基和地球物理监测，在多个尺度上引起了越来越多的关注。在这项研究中，钻了两口现场试验井，一口井位于茂原，一口井深为 880 米，位于日本市原，DFOS 电缆部署在井套管后面。高压水射流试验在127 m深度的恒定位置和300 m井中以1.33 m/min和0.51 m/min的牵引速度在可变喷射位置进行。然后，利用该 DFOS 系统以 1.2 m/min 的下降速度沿 880 m 井的整个长度监测水射流。可以实时监测水射流引起的温度剖面并分析固井质量，以进一步评估井筒完整性。结果表明，两口井的温度异常区具有较好的可比性，固井性较差，与地球物理测井数据相比较好。因此，永久安装的 DFOS 井将提供一种高效且更简单的工具，可以通过现场水射流测试来诊断 CGS 监测项目的井筒完整性。