HR: 0800h
AN: S21B-0567    [Abstracts]
TI: Hydrological and chemical monitoring during Fluid Injection Test in Taiwan Chelungpu-fault Drilling Project
AU: * Murakami, M
EM: masaki@eps.s.u-tokyo.ac.jp
AF: The University of Tokyo, 7-3-1 Hongo Bunkyo-Ku, Tokyo, 113-0033, Japan
AU: Tanaka, H
EM: tanaka@eps.s.u-tokyo.ac.jp
AF: The University of Tokyo, 7-3-1 Hongo Bunkyo-Ku, Tokyo, 113-0033, Japan
AU: Kuo, T
EM: maceggg@gmail.com
AF: National Central University, NO.300 Jung-da Rd, Jung-li, Taoyuan, 320, Taiwan
AU: Tsao, C
EM: 93622002@cc.ncu.edu.tw
AF: National Central University, NO.300 Jung-da Rd, Jung-li, Taoyuan, 320, Taiwan
AU: Giletycz, S
EM: suavciu@yahoo.com
AF: National Central University, NO.300 Jung-da Rd, Jung-li, Taoyuan, 320, Taiwan
AU: Chen, W
EM: dc@earth.ncu.edu.tw
AF: National Central University, NO.300 Jung-da Rd, Jung-li, Taoyuan, 320, Taiwan
AU: Wang, C
EM: wangcy@earth.ncu.edu.tw
AF: National Central University, NO.300 Jung-da Rd, Jung-li, Taoyuan, 320, Taiwan
AU: Chen, C
EM: chenchia@cc.ncu.edu.tw
AF: National Central University, NO.300 Jung-da Rd, Jung-li, Taoyuan, 320, Taiwan
AU: Chen, C
EM: chusen@ncu.edu.tw
AF: National Central University, NO.300 Jung-da Rd, Jung-li, Taoyuan, 320, Taiwan
AU: Yang, T
EM: tyyang@ntu.edu.tw
AF: National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
AU: Ma, K
EM: fong@earth.ncu.edu.tw
AF: National Central University, NO.300 Jung-da Rd, Jung-li, Taoyuan, 320, Taiwan
AB: Taiwan Chelungpu-fault Drilling Project drilled two research boreholes (Hole A and B; approximately 40 m of their distance) through the Chelungpu Fault in Da-Keng, which ruptured in the 1999 Mw 7.6 Chi-Chi earthquake, in 2004. A branched borehole was drilled from Hole B in 2005 (Hole C), and then both Hole A and Hole C were perforated at the depth of the fault zone. The depth of perforation is 1111 m in Hole A and 1137 m in Hole C. Between the two boreholes, Fluid Injection Test (FIT) was performed on from November 2006 to March 2007 to estimate permeability and to understand hydrological and chemical properties along Chelungpu fault. Water was injected four times from Hole C at constant pressure during this FIT (4 MPa on November 2006 and January 2007, 3 and 5 MPa on March 2007). The arrival of injected water was monitored by seismometers, manometers, a Quadrupole Mass Spectrometry and chemical sensors at Hole A. In this present, we will report the results of water quality, gas and water pressure monitoring at Hole A.
During FIT, tap water was used for injected water, which was characterized by high Oxidation Reduction Potential (ORP; 250 mV) and high Dissolved Oxygen (DO; 5.6 mg/L). Because both ORP and DO of the well water at Hole A kept low (ORP; -350 - -150, DO; <0.5 mg/L) before FIT, the arrival of injected water can be found by rise of these values. 1st FIT was performed for approximately 100 hours from 22:00 on 7th to 8:30 on 12th November. As a result, the values of ORP and DO increased on 10th November, which is 3 days after the start of 1st FIT. Then, the flow rate at Hole A suddenly increased 7 days after the first chemical reaction on 10th, that is, 10 days after the start of 1st FIT. This suggests that the permeability is 10^-16 m² assuming that the width of a permeable zone is 1 m by the preliminary estimation of the permeability based on the model of Kitagawa et al. (2002).
DE: 1719 Hydrology
DE: 1734 Seismology
DE: 7209 Earthquake dynamics (1242)
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 8045 Role of fluids
SC: Seismology [S]
MN: 2007 Fall Meeting