水压致裂试验过程中的地电效应研究

本文总结了在水压致裂试验现场多台电法仪器测量和记录到的加压过程中的地电效应,并得到一些能反映岩石破裂情况的有意义的结果:（1）随着压力增加,电阻率明显上升.当压力超过岩石临界应力的一半以后,电阻率即很快地下降,卸压后又逐步回升,其变化椭圆的长轴方向与岩石破裂面的延伸方向是一致的;（2）以压力孔为中心的自然电位及ZK2,ZK14孔的井下电位都伴随着加压过程而变化,强烈反映了过滤电场与孔隙水压力的相关性. 

A STUDY OF THE GEOELECTRIC EFFECT ON THE PROCESS OF HYDRAULIC FRACTURING EXPERIMENTS

In the paper,the geoelectric effects associated with the pressurization measured and recorded by electric instruments in sites of hydraulic fracturing experiments are summarized,and some significant results corresponding to rock failure are also obtained as follows:(1)With the increase of pressure,the resistivity rises distinctly. Affer the pressure has exceeded a half of rock critical stress,the resistivity drops rapidly; and during the release stress,the resistivity gradually rises again.(2)The self-potential centered on the pressure hole and the electric potential in the wells ZK2 and ZK14 change with the pressurization,all reflect strongly the correlation between the percolated electric field and the pore pressure gradient.