CHU T Q, LEI D J, YAN J W, et al.Experimental study on phase frequency spectrum curve of hydraulic fracturing coal[J].Journal of Henan Polytechnic University(Natural Science) ,2023,42(3):34-41.

doi:10.16186/j.cnki.1673-9787.2021110035

Received:2021/11/10

Revised:2022/03/14

Published:2023/05/25

Experimental study on phase frequency spectrum curve of hydraulic fracturing coal

CHU Tianqing1, LEI Dongji1,2, YAN Jiangwei1, CHEN Xinyuan3, LI Jian1, ZHOU Meng1

1.State Key Laboratory Cultivation Base for Gas Geology and Gas Control，Henan Polytechnic University，Jiaozuo  454000，Henan，China;2.Henan Province Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region，Henan Polytechnic University，Jiaozuo  454000，Henan，China;3.Henan Coal Science Research Institute Co.，Ltd.，Zhengzhou  450001，Henan，China

Abstract:In order to study the change law of complex resistivity of the internal structure of coal before and after hydraulic fracturing，hydraulic fracturing experiments of coal under the condition of loading confining pressure were carried out in the laboratory，and the phase and amplitude spectrum curves of coal before and after fracturing were measured.The results showed that：（1）The phase spectrum curve of dry coal before and after fracturing was“U”-shaped，and the phase spectrum curve moved obviously after fracturing；（2）The phase spectrum curve of fracturing coal containing distilled water was“W”-shaped；（3）In fracturing coal，the“W”curve was caused by the inadequate interfacial polarization of the inadequately filled water bearing secondary fractures and the original fractures，which was related to the unevenness of hydraulic fracturing damage to the coal；（4）The equivalent circuit method was used to simulate the process of changing the phase spectrum curve from“W”type to“U”type by using different capacitors instead of coal interface polarization at different frequencies.The results showed that the insufficient interface polarization of inadequately filled water bearing secondary fractures and primary fractures at different frequencies was the reason for the“W”type curve.

Key words:hydraulic fracturing;interface polarization;phase spectrum curve;“W”type curve;equivalent circuit

水力压裂煤体相位频谱曲线试验研究_储天庆.pdf