【摘要】 非常规油气高效开发的关键在于储层的水力压裂改造,微地震监测技术是评价水力压裂施工效果的主要技术.目前微地震监测急需高灵敏度、大带宽的微地震检波器.本文针对微地震监测的需求,设计了一种光纤激光微地震检波器,并与传统的动圈检波器进行了对比.结果表明,这种检波器频带宽度(-3dB)超过500Hz,灵敏度高,高频信噪比高于传统的动圈检波器1个数量级以上,为光纤激光检波器应用于水力压裂的微地震监测提供了实验依据.更多还原

【Abstract】 Hydraulic fracturing has been seen as the key methods of extracting unconventional oil and gas resources,and micro-seismic monitoring technology is the major technology to evaluate the effect of hydraulic fracturing. Microseismic monitoring also is used for reservoir monitoring of thermal processes, drill-cuttings injection, geothermal hotdry-rock stimulations,reservoir surveillance,and many other processes in oil and gas and mining. As very small earthquakes(microseisms)induced by downhole process need to be detected and located to provide geometric and behavioral information about the process,and typically,microseisms associated with fracturing dominant frequencies extending from 200 to approximately 1kHz,micro-seismic monitoring needs very high sensitivity, large bandwidth micro-seismic geophones.Traditional coil geophones may not be suitable for microseismic monitoring for not enough high frequency sensitivity.Fiber optic geophones have potentially advantages such as more sensitive,improved high frequency response,high temperature capable and immune to electromagnetic interference.The fiber laser based geophone technology has been fast developing in recent years and it is likely to replace the existing coil geophones due to their high sensitivity,ease of multiplexing and compact size.In this paper,a fiber laser micro-seismic geophone based on an L shape beam structure is designed and is compared with the traditional coil geophone. The test is focused on the high frequency response of the two kind geophones.The results show that the fiber laser micro-seismic geophone has a flat frequency response up to 500 Hz,a very high sensitivity an better high-frequency signal to noise ratio than traditional coil geophone,indicates that the fiber laser geophone high frequency sensitivity is 10 times higher than conventional.The possible of using fiber laser micro-seismic geophone in micro-seismic monitoring are also discussed.This paper provide an investigation and experimental basis for the use of fiber laser micro-seismic geophone in the micro-seismic monitoring of hydraulic fracturing.更多还原