Development of Continuous and Multi-component Gas ... · fast flow of water and the oil contained...

Development of Continuous and Multi-component Gas Monitoring

System for Groundwater

TSUNOMORI　FumiakiLaboratory for Earthquake Chemistry,

Graduate School of Science, University of Tokyo

Japan-Taiwan International Workshop on Hydrological and Geochemical Research for Earthquake Prediction, Sep. 24, 2002

1

Outline

• Background• Observation• Result & Discussion• Problems• Summary


2

Background


3

State of Gas Seismology• Although a lot of authors had reported gas anomalies before earthquakes, a systematic method to reduce external perturbations from geochemical signals is not realized still now.• Gas seismology cannot provide a practical method to predict earthquakes.• A comprehensive measurement system will be necessary to promote the earthquake prediction with gas seismology.We have produced a new system to monitor gas

composition in groundwater together with a lot of associated parameters.


4

Observation


5

StationsSOMKSM

KS2KS3

NRH

KMK

OSM

EDYHRNSKERHB

OMZ

YSD

RYO

Old SystemNew System

100km


6

Method to extract gases• A gas extraction module (Nagayanagi Co.) is used to

extract gases from groundwater.

• 3000 silicone hollow fibers are bundled inside a housing. Both sides of fibers are fixed to a left and right block of the housing with silicone resin. Liquid water cannot pass through the surface of a fiber.

20cm3µm


7

Circulation Type Water Pumping• A circular type water pumping system let us to

monitor the water level together with gas monitoring.

To gas analyzerAquifer


8

Apparatuses

Well

Pump

Gas Extraction

Module

Quadrupole Mass

Spectrometer(ULVAC STANDAM)

Radon Counter

(SARAD RM2000)

Pump

• 4He, CH4, H2O, N2, O2, 36Ar, 40Ar, CO2• Interval = 1 sec.

• 222Rn• Interval = 1 min.

A/D Converter

• Water level, Water temp., Atm. Pressure, Flow rate, Rain fall, Room temp.• Interval = 1 sec.

Vacuum Line


9

Omaezaki 100m Well

QMSWellPCs

Radon meter


10

Result&

Discussion


11

Gas Concentration in Groundwater

10-14

10-12

10-10

10-8

10-6

10-4

10-2

2000/7 2001/1 2001/7 2002/1 2002/7

PressureM=2M=4M=15M=18M=28M=32M=36M=40M=44

Cur

rent

/A

Date

Background level

1. The aquifer is a closed system.Though the permeability of the aquifer at the 100m

well at Omaezaki station is high, the gas concentration decreased. If groundwater is exchanged between the aquifer and the other one, the gas concentration will be constant. The result shows that gases would not be supplied from outside of the aquifer.

2. The sensitivity of a QMS detector is changed.No automatic calibration system is used. Such a system

is needed to know the sensitivity of the detector.


12

Temporal Variation in CH4/Ar Ratio• At Omaezaki in Aug.-Sep., 2000

2.20

2.30

2.40

2.50

2.60

2.70

0 100 200 300 400

CH

4/Ar

Time /Hour


13

BAYTAP Analysis of CH4/Ar

2.30

2.50

2.70

0 100 200 300 400

CH

4/Ar

Time /Hour

2.30

2.50

2.70

0 100 200 300 400

CH

4/Ar

Time /Hour

-0.20

0.00

0.20

0 100 200 300 400

CH

4/Ar

Time /Hour

-0.20

0.00

0.20

0 100 200 300 400C

H4/A

rTime /Hour

Original Data

Trend Comp.

Tidal Comp.

Residuals

0.000

0.004

0.008

0.012

0.016

O1 K1 M2 S2 M3

Am

plitu

de

Component

Gas ratio responds to the earth tide.


14

Problems


15

Technical Problems1. A gas extraction module is easily affected by both the fast flow of water and the oil contained in groundwater.2. QMS is damaged by condensed dews. Water vapor is actually the main component of extracted gases.3. QMS in the observation sites is not calibrated. Ionization efficiency of a filament in a QMS chamber is a little bit changed when the filament is replaced.


16

Scientific Problems• Why do gases respond to the earth tide?

A few papers actually reported the gas emission by the rock fracture. However the relation between rock fracture process and gas emission is not studied yet.

Stress

Stress Gas

Crack


17

Summary


18

In This Presentation• Development of a multi-component gas monitoring system is going on our project. Characteristics of our system are as follows:

1. Gas extraction module2. Circulation type water pumping3. Comprehensive measurement system

• Gas ratio such as CH4/Ar responds to the earth tide.• There are some problems for the apparatus.

– Strength of a gas extraction module– Water problem


19

Thank you for your attention


20

Appendices


21

Lab. for Earthquake Chemistry• Our laboratory was established in 1978 to develop the science for earthquake prediction from the geochemical viewpoint.• Observations for 222Rn concentration in groundwater have been continued at east Fukushima, Izu peninsula, and Tokai areas.• We have produced a new system to monitor multi-component gas in groundwater together with a lot of associated parameters.


22

Kobe Earthquake

Earthquake

G. Igarashi, et. al., Science, 269, 60-61, 1995.

G. Igarashi, et. al., Geophys. Res. Lett., 19(15), 1583-1586, 1992.


23

Temperature of Aquifer

30.0430.0830.1230.1630.20

0 3000 6000 9000 12000

UpperLower

Tem

pera

ture

/o C

Time /s

0.006

0.007

0.008

0 3000 6000 9000 12000

Upper Detail /deg.Lower Detail /deg.

Tem

pera

ture

/o C

Time /s

100m

Strainer00:00:00 – 03:25:12, 14th May, 2002


24

Data Transfer

Station

Apparatus

Apparatus Apparatus

T/A

Local Server

University

Processor

Controller Web Server

T/A

Data Server

Internet


25

Tidal Responses of Gas Ratio

0.98

1.00

1.02

1.04

1.06

0 100 200 300 400

CO

2/Ar

Time /Hour

4.1

4.2

4.3

4.4

4.5

0 100 200 300 400

36A

r/40A

r

Time /Hour

8.0

9.0

10.0

11.0

12.0

13.0

0 100 200 300 400

O2/A

r

Time /Hour

5.60

5.70

5.80

5.90

6.00

0 100 200 300 400

N2/A

r

Time /Hour

1.60

1.70

1.80

1.90

2.00

0 100 200 300 400

H2O

/Ar

Time /Hour

0.95

1.00

1.05

1.10

1.15

0 100 200 300 400

He/

Ar

Time /Hour


26

BAYTAP Analysis• Amplitude of components

-4398.41-3251.03-1644.3-3540.29-3404.18-3754.73-3901.67

ABIC

0.0110.0040.0370.006N2

0.2330.0440.6860.123O2

0.0130.0050.0400.01036Ar

0.0050.0000.0120.002He0.0100.0110.0120.008CH4

CO2

H2O

0.001

0.009

O1

0.008

0.051

K1

0.002

0.005

M2 S2

0.003

0.020


27

Frequency Analysis of CH4/Ar• Maximum entropy method (MEM)

Interval /Hour

Pow

er /a

.u.

0

1

2

3

4

10 15 20 25 30 35 40 45 50

12.3 hour

25.4 hour


28

Temperature Dependence of Gas Separation Coefficient


29

Pressure Recovery Test


30

Temperature Dependence of Gas Permeation Rate

Effect of solubility increase of gases to water

Effect of diffusion of gases in membrane


31

Our Long-term Objectives1. Detect geochemical changes in groundwater.2. Reveal the generation process of geochemical precursors from the viewpoint of rock fracturing.

3. Understand geochemical signals before earthquakes, and produce systematic and practical method to predict earthquakes.


32

In Future• To redesign the structure of a gas extraction module, to

change resin for fixing silicone hollow fibers, or to alter method to extract gases.

• To develop an automatic calibration system for QMS.• To study on the emitted gases in the fracture process of

rocks will be carried out in order to reveal the mechanism of tidal response of the gas ratio.


33

Rock Fracturing Chemistry

Detailed measurement of emitted gases

Measurement of the crack growth by AE

• Relationship between the crack growth and the emission pattern of gases

• Relationship between total volume of emitted gases and a kind of a rock

Rock Fracturing


34

Group Members

AssistantProfessorGeorge Igarashi

UndergraduateStudentKeika Horiguchi


35

Lab. Staff

DirectorProfessorNagao Keisuke

ProfessorNotsu Kenji

AssistantProfessorKagi Hiroyuki

AssistantProfessorGeorge Igarashi

ResearchAssistantSumino Hirochika

ResearchAssistantMori Toshiya

Development of Continuous and Multi-component Gas ... · fast flow of water and the oil contained...

Documents

Transcript of Development of Continuous and Multi-component Gas ... · fast flow of water and the oil contained...