Study on connectivity of water-conducting features in a fractured rock based on the fluid logging and hydraulic packer testing

流体電気伝導度検層と水理試験による亀裂性岩盤中の水みちの連続性に関する検討

竹内 真司; 竹内 竜史  ; 戸谷 成寿*; 大丸 修二

Takeuchi, Shinji; Takeuchi, Ryuji; Toya, Naruhisa*; Daimaru, Shuji

We established a methodology of investigations and analysis for estimating the connectivity of WCFs of a fractured rock mass. The flowing fluid electrical conductivity (FFEC) logging, one of the effective methods for identifying WCFs with high resolution, was conducted. Then hydraulic packer testing (HT) was carried out on each WCF. Transmissivity normalized plot (TNP) based on the pressure derivative plots, which can show time changes of transmissivity values, was then applied to the results of HT. The above series of methods has been applied to several fractured zones along boreholes. The results indicate almost the same value of transmissivity for each WCF in the fractured zone as the one of entire zone with similar orientation. Hydrochemical values are almost the same in each WCF. We conclude that the series of methodology of TNP analysis based on the HT focusing on the WCFs from FFEC logging results is a useful tool for evaluating the connectivity of WCFs.