煤系页岩水力压裂声发射时频特征试验研究

发布时间：2018-03-25 02:33

本文选题：水力压裂　切入点：裂缝起裂　出处：《中国安全科学学报》2017年10期

【摘要】：为深入研究煤系页岩的水力压裂过程及特征,以阜新孙家湾矿煤系页岩为研究对象,首先采用三轴水力压裂模拟装置进行实验室压裂模拟试验;然后利用短时傅里叶变换(STFT)对所得原始声发射信号进行时频转换,得到时频参数与裂缝起裂、扩展间关系规律。研究结果表明:幅值变化率可以作为判断起裂阶段与扩展阶段的指标,起裂阶段幅值变化率随水平地应力差增大而增大,扩展阶段幅值变化率随水平地应力差增大而先增大后减小;水平地应力差为0、0.2和0.4 MPa时,起裂阶段幅值变化率分别是扩展阶段的2.88、3.14和5.36倍;裂缝起裂与扩展阶段主频大小与水平地应力差均成线性递减关系;进入扩展阶段,主频增加至起裂阶段的2、1.96和1.99倍。
[Abstract]:In order to deeply study the hydraulic fracturing process and characteristics of coal-measure shale, taking the coal-measure shale of Sunjiawan Mine in Fuxin as the object of study, a three-axis hydraulic fracturing simulator was first used for the laboratory fracturing simulation test. Then the time-frequency conversion of the original acoustic emission signal is carried out by using STFT, and the time-frequency parameters and the crack initiation are obtained. The results show that the amplitude change rate can be used as an index to judge the initiation and extension stages, and the amplitude change rate of the initial crack stage increases with the increase of horizontal ground stress difference. When the horizontal stress difference is 0 ~ 0. 2 and 0. 4 MPa, the amplitude change rate of initiation stage is 2.88 ~ 3.14 and 5.36 times of that of extension phase, respectively, when the horizontal stress difference increases firstly and then decreases with the increase of horizontal stress difference. The main frequency decreases linearly with the horizontal stress difference in the fracture initiation and propagation stages, and increases to 21.96 and 1.99 times of the initial crack initiation stage.
【作者单位】：辽宁工程技术大学力学与工程学院;
【基金】：国家重点研发计划(2016YFC0600901) 国家自然科学基金面上项目资助(51374119) 辽宁省高等学校优秀人才支持计划(LR2015028) 辽宁省自然科学基金资助(2014020156)
【分类号】：TD83

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