Project Subjects
CO2 Storage Technology
Background and Objective
It is necessary to use coal which is evaluated to have huge potential in the world for supplying a stablesource of electricity in the future. However it is also needed to reduce CO2 emissions from thermal power plants
into the atmosphere for preventing global warming. Therefore CCS technology which captures CO2 from thermal
power plants and storages into underground is being developed.
In this project, we collected information on the latest CCS activities in Japan and from around the world,and developed technologies for storing CO2 underground considering the characteristics of geological structures
around thermal plants in Japan.

Main results
1. Site evaluation technology
At coastal areas underground which are considered as CO2 storage candidate sites, the geological structure
and tectonics affecting occurrence and activity of faults were summarized and the characteristics of faults in eacharea were also summarized. An investigation and evaluation ﬂow of faults at coastal areas which are considered
as candidate sites were also proposed (Fig. 1).
These results were obtained through the funded research of the Research Institute of Innovative Technology for the Earth (RITE).
2. Understanding CO2 performance
It is conﬁrmed that calcium carbonate (CaCO3) crystal grew 2.2 micro meters in three hours in the ﬁeldexperiments where CO2 dissolved water containing 0.4% or 0.8% of CO2 was injected into rock at a temperatureof around 200 degrees Celsius through the 1,100 m deep well. These results showed that CO2 can be stored ascarbonate minerals relatively faster at high temperature condition. It was found that electric resistivity in the wellsuddenly decreased by injecting CO2 dissolved water. This result showed that the electrical survey will be effective for CO2 distribution monitoring (Fig. 3).
3. Monitoring technology
CO2 detecting and monitoring methods around sea ﬂoors were proposed with developing elastic wave
tomography equipment set on the sea ﬂoor and introducing AUV with attaching some chemical sensors [V09034][V09035]. Numerical simulation showed that gravity and electric self-potential would decrease of about 70 micro
gal and about 200 millivolts respectively when a total of 5 million tons of CO2 is injected into undergroundthrough a well at a depth of 950m. Therefore these methods can be used for CO2 distribution monitoring.
4. Environmental effect evaluation in the sea
It was shown that CO2 diffusion in the sea around Japan can be analytically estimated by using a highresolution regional sea model with horizontal resolution of 10 km.
5. CCS activity survey in Japan and the world
CCS obligation standard in Britain was summarized as a result of the world CCS activity survey [V09010].
The process for residential acceptance for CCS in the ZeroGen Project in Australia was summarized [V09004].
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Stable Power Supply Technology
Planning of borehole survey in sea area

Investigation of hydrologic characterizationof fault in sea area

<Geological survey of the fault in the from sea
area>
In-situ experiment (hydraulic conductivity，porewater pressure, crosshole tomography),
Borehole logging (self-potential, resistivity,density, sonic, P- and S-wave velocity,temperature, flowmeter), Borehole television ，Water sampling (water quality test, pH, oxidationreduction potential), Laboratory experiment(physical and mechanical test), Simulation

Planning of borehole layout<Survey items>
Core logging (fault gouge, fracture zone, cutting
relation of faults and fractures), Orientation of
fault and fracture, fracture frequency (boreholetelevision), Permeability and connectivity offault (cross hole hydraulic test), Continuity offault, Determination of the period when thefault was formed (dating)

Vertical seismic profiling (VSP),
Cross hole test

Two boreholes arearranged across eachsegment of the fault

Borehole drilling

Borehole logging,
In-situ experiment

Geologic cross section around
fault zone (detail 3D model)
Hydrologic modeling aroundfault<Evaluation Items>
Quality of seal layer in a storage area
Cutting relation between fault and seal layer
Permeability and seal capacity of fault andfracture zone
Activity of fault (activity, age of fault movement）
Possibility of CO2 leakage via fault

Characteristics of fault>>Fault structure>>Permeability>>Continuity

Analysis of groundwater flow
(main analysis)
Monitoring

Fig. 1 Preliminary investigation ﬂow of hydrologic characterization of fault at coastal areas
This study was carried out through the funded research of the Research Institute of Innovative Technology for the Earth (RITE)(3)

5.7μm(μm)(1)

CO2 dissolved water arrival

500
100

Resistivity(0.4wt%CO2)

700 m

200 ℃

1,100 m(μm)

100BA

test2-1

2CO2dissolved 1water
0V=0.206nm/s
反応前
2,224
2,224nmnm
反応後Water temp.(0.4wt%CO2)

300

120

200

80

10050

Crystal grow(2)
test tool

100150

0(μm)

05040

CO2濃度が高くなるとCO2 dissolved water
比抵抗は小さくなる

Surface water

0160

Water temp.(0.8wt%CO2)

Temperature (℃)

200 (μm)-3. 8μm00Resistivity (Ωm)

400(4)200Resistivity(0.8wt%CO2)

100150200
Elapsed time (min)2503000Gold film

Calcite Crystal

Fig. 2 Calcite crystal growth test result
CO2 dissolved water was injected into rock at a depth of
1,100 m and at a temperature of 200 degrees C. (1) Calcite
crystal sample was suspended in the well at 950 m depthfor three hours. (2) The sample was partially covered withgold ﬁlm. (3) The crystal surface was observed by microscope. (4) The surface in the reacted area was measured tohave grown about 2.2 micrometers.
(Collaboration research results with RITE)

Fig. 3 Electric resistivity in the well change
during CO2 dissolved water injection
Electric resistivity change was detected by the resistivity
log in the well during CO2 dissolved water injection likein the Fig. 2 test. These results showed that the electric
resistivity measurement can be used as a CO2 monitoring
method.

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