煤矿水力压裂分布式光纤传感监测技术研究进展

Research Progress on Distributed Fiber Optic Sensing Monitoring Technology for Hydraulic Fracturing in Coal Mines

  • 摘要: 为解决深部煤层气开发中水力压裂裂缝形态监测困难、传统点式监测手段易造成信息缺失等问题,系统评估分布式光纤传感技术(DFOS)在煤矿压裂监测中的应用潜力与技术瓶颈。基于光纤传感原理,系统梳理了分布式光纤声波传感(DAS)、温度传感(DTS)与应变传感(DSS)三种技术的监测机制;结合煤岩体低弹性模量、强非均质性等地质特征,深入分析了不同传感技术在裂缝几何反演、流体示踪及微震捕捉中的适用性与局限性。分析表明,DAS对裂缝动态扩展的声学响应敏感,DTS擅长流体运移路径示踪,而DSS则能精细表征近井筒应变场;三者在时空尺度上具有显著的互补性。由于煤岩特殊的力学性质导致光纤应变传递效率低,且含气煤层对高频声波具有强衰减效应,限制了单一技术的监测精度和解释唯一性,多源信息融合是克服复杂缝网反演多解性的关键途径。未来研究应重点聚焦于适配松软煤层的低模量高增摩封装材料研发、基于人工智能的弱信号解调算法以及热−流−固多物理场耦合反演模型的构建,以实现煤矿水力压裂的智能化精准监测。

     

    Abstract: In response to the challenges associated with monitoring fracture patterns during hydraulic fracturing in deep coal mines and the potential information loss inherent in traditional point−based monitoring methods, this paper explores the potential and technical limitations of distributed fiber optic sensing (DFOS) technology in hydraulic fracturing monitoring. Based on the principles of fiber optic sensing, the monitoring mechanisms of Distributed Acoustic Sensing (DAS), Distributed Temperature Sensing (DTS), and Distributed Strain Sensing (DSS) are systematically reviewed. Considering the geological characteristics of coal and rock masses—such as low elastic modulus and strong heterogeneity—the applicability and limitations of different sensing technologies in fracture geometry inversion, fluid tracing, and microseismic detection are analyzed. The analysis shows that DAS is sensitive to the acoustic response generated during dynamic fracture propagation, DTS excels at tracing fluid migration pathways, and DSS provides precise characterization of the strain field near the wellbore. Thus, these three technologies exhibit significant complementarity across both temporal and spatial scales. Due to the unique mechanical properties of coal and rock, the efficiency of strain transfer to the optical fiber is relatively low. Moreover, gas−bearing coal seams strongly attenuate high−frequency acoustic waves, which limits the monitoring accuracy of individual technologies and leads to non−unique interpretation results. Multi−source information fusion is key to overcoming the inversion ambiguities associated with complex fracture networks. Future research should focus on developing low−modulus, high−friction encapsulation materials suitable for soft coal seams, constructing artificial intelligence−based weak−signal demodulation algorithms, and establishing coupled thermal–hydrological–mechanical (THM) inversion models. These efforts will contribute to achieving intelligent and precise monitoring of hydraulic fracturing in coal mines.

     

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