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Analyzing pressure responses to Earth Analyzing pressure responses to Earth tides for monitoring COtides for monitoring CO22 migration migration
Kozo SatoGeosystem EngineeringThe University of Tokyo
ObjectiveObjective
Monitoring techs for geological sequestration
seismic (4D, VSP, cross-well tomography) non-seismic (electromagnetic, gravity, tilting, logging)
Alternative technique? cost-effective labor-saving
Utilize pressure responses to Earth tides perturbation by the M and the S (no artificial energy
required) pressure measurements only (no extra operation required)
OutlineOutline
Objective Tidal deformations
Earth tide Cubic dilatation Calculation of Cubic dilatation
Poroelasticity Tidal signals in pressure responses Results and discussion Concluding remarks
Tidal deformationsTidal deformations
Earth tide Tidal deformation (cyclic compaction and expansion) of the
solid Earth phenomenon similar to ocean tides the gravitational attraction of the solar system bodies: M
and S
Tidal deformationsTidal deformations
Cubic dilatation cubic dilatation (trace of strain matrix)
normal stresses and strains
near the Earth surfacefree surface boundary condition 0rr
rr
iiii 2
)(2
2
Tidal deformationsTidal deformations
Calculation of cubic dilatation as a linear combination of Y and its derivatives w.r.t.
Y: spherical harmonics defining tidal potential
sample calculation of (an onshore site, Nagaoka, Japan)(latitude: 37.40, longitude: 138.70)
2
0
2 ),()/(m
mmYcargV
)/,,()/,,( 22 YYYY
OutlineOutline
Objective Tidal deformations Poroelasticity
Deformations and pressure fluctuation and CO2 migration
Tidal signals in pressure responses Results and discussion Concluding remarks
PoroelasticityPoroelasticity
Deformations and pressure fluctuation tidal deformation induces pressure fluctuation p
Biot-Gassmann equation
poroelastic parameter
KKp
u
1
2
sfu KK
KK
sf KKp
1
PoroelasticityPoroelasticity
and CO2 migration Kf for the H2O-CO2 system
as a function of SCO2
sf KK
1
222
11)1(
1
COCO
wCO
f KS
KS
K
PoroelasticityPoroelasticity
and CO2 migration Kf for the H2O-CO2 system
as a function of SCO2
KCO2=0.003~0.07GPa, Kw=2.4GPa @1000m increases as SCO2 increases: =ASCO2+B
=/p : a good indicator for monitoring the CO2 migration
BAS
KKS
KK
CO
swCO
wCO
2
22
111
222
11)1(
1
COCO
wCO
f KS
KS
K
OutlineOutline
Objective Tidal deformations Poroelasticity Tidal signals in pressure responses
Pressure responses Retrieving p(t) from p(t)
Results and discussion Concluding remarks
Tidal signals in pressure responsesTidal signals in pressure responses
Pressure responses long-term pressure trend pt(t)
associated with a certain event, s.a. CO2 sequestration
Tidal signals in pressure responsesTidal signals in pressure responses
Pressure responses long-term pressure trend pt(t)
associated with a certain event, s.a. CO2 sequestration total pressure response p(t) : superposition of pt(t) and p(t) p(t): tidal signal induced by the Earth tide
)()()( tptptp t
Tidal signals in pressure responsesTidal signals in pressure responses
Retrieving p(t) from p(t) model the long-term pressure trend with the cubic spline
retrieve the tidal signals
n
jjjt ptNtp
1
)()(
)()()( tptptp t
p(t) pt(t)
Tidal signals in pressure responsesTidal signals in pressure responses
Retrieving p(t) from p(t) model the long-term pressure trend with the cubic spline
retrieve the tidal signals
p(t) pt(t) p(t)
n
jjjt ptNtp
1
)()(
)()()( tptptp t
OutlineOutline
Objective Tidal deformations Poroelasticity Tidal signals in pressure responses Results and discussion
Monitoring at a sequestration test field Estimation of Detection of CO2 arrival
Concluding remarks
Results and discussionResults and discussion
Monitoring at a sequestration test field onshore aquifer, Nagaoka, Japan sandston bed, thickness: 60m, depth: 1100m injection well: CO2-1, Zone-2a (6m) and Zone-2b (6m) monitoring wells: CO2-2, CO2-3, CO2-4
CO2-4
CO2-2
CO2-3
CO2-1
60m
120m
40m
loggingpressure measurements
logging
logging
Results and discussionResults and discussion
Monitoring at a sequestration test field pressure measurement time-lapse sonic logging (compressional wave velocity)
Results and discussionResults and discussion
Monitoring at a sequestration test field is it possible to detect CO2 arrival only with pressure
data? =ASCO2+B
Results and discussionResults and discussion
Estimation of (132-139 days) calculation of
Results and discussionResults and discussion
Estimation of (132-139 days) p retrieved from the pressure data
Results and discussionResults and discussion
Estimation of (132-139 days) =/p scaled to match the p profile
Results and discussionResults and discussion
Estimation of (132-139 days) =/p scaled to match the p profile 1GPa 17.0
p
Results and discussionResults and discussion
Estimation of (387-394 days) calculation of
Results and discussionResults and discussion
Estimation of (387-394 days) p retrieved from the pressure data
Results and discussionResults and discussion
Estimation of (387-394 days) =/p scaled to match the p profile
Results and discussionResults and discussion
Estimation of (387-394 days) =/p scaled to match the p profile 1GPa 40.0
p
Results and discussionResults and discussion
Detection of CO2 arrival
1GPa 40.0
p
1GPa 17.0
p
Results and discussionResults and discussion
Detection of CO2 arrival time-lapse estimation (13 intervals)
Results and discussionResults and discussion
Detection of CO2 arrival time-lapse estimation (13 intervals) =ASCO2+B
Results and discussionResults and discussion
Detection of CO2 arrival time-lapse estimation (13 intervals) =ASCO2+B
Results and discussionResults and discussion
Detection of CO2 arrival time-lapse estimation (13 intervals) =ASCO2+B
OutlineOutline
Objective Tidal deformations Poroelasticity Tidal signals in pressure responses Results and discussion Concluding remarks
Concluding remarksConcluding remarks
The poroelastic parameter , a function of SCO2, can be estimated from p and .
The CO2 migration can be monitored with time-lapse estimations of .
The technique is applicable to well-developed sites (depleted o/g reservoirs).
