长阳页岩气试验井压裂微震检测及特征

Fracture Microseismic Detection and Characteristics of Changyang Shale Gas Test Well

  • 摘要: 基于三峡地震台网2017年7—8月记录到的长阳地区发生的震群资料,通过PhaseNet进行震相识别、REAL震相关联、HypoInverse绝对定位、HypoDD相对定位等定位流程,构建了长阳页岩气试验井压裂震群的高分辨率地震目录。震群重定位结果表明:地震序列整体上沿着地表由南向北呈带状展布;在长阳页岩气试验井水力压裂前后,长阳地区的地震活动性非常低,但在试验井开始压裂期间,整体地震活动性猛增,最大震级可达ML3.4,但震群活动对周边区域地震活动性的影响较小;该震群成因可能为页岩气开采试验井水力压裂导致天阳坪断裂活化产生的。

     

    Abstract: Based on the data of the seismic swarm occurred in Changyang area recorded by the Three Gorges Reservoir seismic network from July 2017 to August 2017, the high-resolution seismic catalog of the fracturing seismic swarm of the Changyang shale gas test well was constructed through the relocation processes of PhaseNet for seismic phase identification, REAL for earthquake association, HypoInverse for absolute relocation, and HypoDD for relative relocation. The relocation results of the swarm showed that the seismic sequence as a whole was spread in a band along the ground surface from south to north. The seismic activity in the Changyang area was very low before and after the hydraulic fracturing of the Changyang test wells. However, during the start of fracturing of the test well, the overall seismic activity increased dramatically with a maximum magnitude of ML3.4, but the swarm activity had little impact on the seismic activity in the surrounding area. This swarm may be generated by the activation of the Tianyangping fracture due to the hydraulic fracturing of the shale gas extraction test well.

     

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