assessing potential impacts of co2 upward migration on
TRANSCRIPT
Assessing potential impacts of CO2 upward migration on drinking groundwater quality at the SECARB Phase
III early test site
GCCC Digital Publication Series #13-28
C. Yang S. D. Hovorka R. H. Trevino
Cited as: Yang, C., Hovorka, S.D., and Trevino, R.H., 2013, Assessing potential impacts of CO2 upward migration on drinking groundwater quality at the SECARB Phase III early test site: presented at the 2013 Carbon Storage RD Project Review Meeting, Pittsburgh, Pennsylvania, 20-22 August 2013. GCCC Digital Publication Series #13-28.
Keywords: Field study-Cranfield-MS; Monitoring-groundwater-USDW
0.0E+00
2.0E-09
4.0E-09
6.0E-09
8.0E-09
0 5 10 15 20
As
co
nce
ntr
atio
n (
M)
Elpased time during the pulling phase (hr)
Modeled w/o surface complexes
Modeled w/ surface complexes
meas.
Assessing Potential Impacts of CO2 Upward Migration on Drinking Groundwater Quality at the SECARB Phase III Early Test Site
Changbing Yang, Susan Hovorka, Ramon Trevino
Gulf Coast Carbon Center, Bureau of Economic Geology, The University of Texas at Austin
10100 Burnet Rd., Austin, TX 78758, [email protected]
1. Introduction
6. Results
This study was funded through the Southeastern Regional Carbon Sequestration Partnership’s (SECARB) Phase III research project by the
U.S. Department of Energy’s National Energy Technology Laboratory (DOE/NETL) under DE-FC26-05NT42590 and managed by the
Southern States Energy Board (SSEB). It was also partially funded by Water Research Foundation (Project No. 4265). We thank the
Denbury Resources Cranfield team and Denbury management for allowing us access to the field. Thanks are given to the Bureau of
Economic Geology research team, Bridget Scanlon, Pat, Mickler, J.P Nicot, Katherine Romanak, and Bob Reedy.
2. Cranfield shallow aquifer
Located 15 miles east
of Natchez, MS
Oil field was
discovered in 1940s
and abandoned in
1960s
Injection of CO2 for
EOR conducted since
2008
Injection phase: inject CO2-saturated groundwater into target aquifer
Resting phase: let injected water react with aquifer sediments
Pulling phase: pump groundwater continuously to collect water samples
Yang, C., Samper, J., and Molinero, J., 2008. Inverse microbial and geochemical reactive transport models in porous media. Physics and Chemistry of the Earth, Parts A/B/C 33, 1026–1034.
Yang, C., Mickler, P. J., Reedy, R., Scanlon, B. R., Romanak, K. D., Nicot, J.-P., Hovorka, S. D., Trevino, R. H., and Larson, T., 2013. Single-well push-pull test for assessing potential impacts of CO2 leakage on groundwater quality in
a shallow Gulf Coast aquifer in Cranfield, Mississippi. International Journal of Greenhouse Gas Control, in press.
Yang, C., Romanak, K., Hovorka, S. D., Holt, R. M., Lindner, J., and Trevino, R., 2013. Near-surface monitoring of large-volume CO2 injection at Cranfield: Early field test of SECARB Phase III. SPE Journal 18, pp. 486–494.
4. Single-well push-pull test 3. Batch experiments
7. Concluding remarks
Results of batch experiments, the field controlled-release test, and
numerical modeling show that DIC and pH are sensitive to CO2 leakage
and may be used for detecting CO2 leakage at the Cranfield shallow
aquifer.
Dominant geochemical processes for ion mobilization may include
dissolution of carbonates and silicates and desorption/adsorption from
clay surfaces.
No obvious degradation in groundwater quality was observed in the batch
experiments and the field test.
Maximum concentrations of trace metals measured, such as As and Pb,
are much smaller than EPA-specified contamination levels.
The single-well push-pull test appears to be a convenient field-scale
controlled-release test for assessing potential impacts of CO2 leakage on
drinking groundwater resources.
The combined use of laboratory batch experiments, field-scale controlled-
release tests, and reactive-transport models provides a comprehensive
evaluation of potential impacts of CO2 leakage on groundwater chemistry.
Conducted to understand responses of
groundwater chemistry to CO2 leakage under
laboratory conditions
106 g of sedimentary samples and 420 ml
groundwater from Cranfield shallow aquifer
Bubbled with Ar for a week, then with CO2
for ~half year
Understanding potential impacts of CO2 upward migration on
underground drinking resources is a critical concern for geologic
carbon sequestration. A comprehensive groundwater study has
been conducted at the Cranfield shallow aquifer, Natchez, MS—
the SECARB Phase III early test site—using a combined
approach of laboratory batch experiment, single-well push-pull
test, and reactive-transport modeling to assess potential impacts
of upward migration of CO2 on groundwater quality.
Implementation:
Injection started : ~3,825 L water over 8 hours
Resting phase: ~55 hours
Pumping phase: ~15,142 L groundwater pumped out over ~11 hours
Onsite measurements
pH, alkalinity
conductivity
temperature
IC analysis
ICP-MS
analysis
DIC and stable
carbon isotope
of DIC
Water samples
5. Reactive-transport modeling
For this study we used CORE2D V4,
a code for modeling partly or fully
saturated water flow, heat transport,
and multicomponent reactive solute
transport under both local chemical
equilibrium and kinetic conditions.
Pros: easy to
do, low cost
Cons:
disturbed
conditions
4
5
6
7
8
9
0 200 400 600 800
pH
Time (hours)
Meas.Model
0.0E+00
1.0E-02
2.0E-02
3.0E-02
4.0E-02
0 200 400 600 800
DIC
Time (hours)
Model
pH DIC
3.0E-04
6.0E-04
9.0E-04
1.2E-03
0 200 400 600 800
Ca
(mo
l/L)
Time (hours)
Meas.Model
1.0E-04
4.0E-04
7.0E-04
1.0E-03
0 200 400 600 800
Mg
(mo
l/L)
Time (hours)
Meas.Model
0.0E+00
4.0E-04
8.0E-04
1.2E-03
0 200 400 600 800
Si (
mo
l/L)
Time (hours)
Meas.Model
0.0E+00
5.0E-05
1.0E-04
1.5E-04
2.0E-04
2.5E-04
0 200 400 600 800
K (
mo
l/L)
Time (hours)
Meas.Model
Dissolution of silicates
Dissolution of carbonates
0.0E+00
4.0E-07
8.0E-07
1.2E-06
1.6E-06
0 200 400 600 800
Ba
(mo
l/L)
Time (hours)
Meas.Model
0.0E+00
6.0E-09
1.2E-08
1.8E-08
2.4E-08
3.0E-08
3.6E-08
0 200 400 600 800
As
(mo
l/L)
Time (hours)
Meas.Model
1) Dissolution of carbonates
such as Ba, Mn, Sr
Mobilization of trace
metals dominated by
two mechanisms:
2) Desorption/adsorption
of metals such as As, Pb
0.0E+00
4.0E-04
8.0E-04
1.2E-03
1.6E-03
0 5 10 15
Br
con
cen
trat
ion
(M
)
Elpased time during the pulling phase (hr)
Modeled
meas.
3
4
5
6
7
8
0 5 10 15 20
pH
Elpased time during the pulling phase (hr)
Modeled w/o mineral dissolution
Modeled w/ mineral dissolution
meas.
0.0E+00
5.0E-04
1.0E-03
1.5E-03
2.0E-03
2.5E-03
0 5 10 15 20
Alk
alin
ity
(mo
l/L)
Elpased time during the pulling phase (hr)
Modeled w/o mineraldissolutionModeled w/ mineraldissolutionmeas.
pH Alkalinity
3.0E-05
3.5E-05
4.0E-05
4.5E-05
0 5 10 15 20
K c
on
cen
tra
tio
n (
M)
Elpased time during the pulling phase (hr)
Modeled w/o silicates
Modeled w/ silicates
meas.
3.0E-04
5.0E-04
7.0E-04
9.0E-04
0 5 10 15 20
Si c
on
cen
trat
ion
(M
)
Elpased time during the pulling phase (hr)
Modeled w/o silicates
Modeled w/ silicates
meas.
K Si
Dissolution of silicates
Dissolution of carbonates
4.0E-04
4.4E-04
4.8E-04
5.2E-04
5.6E-04
6.0E-04
0 5 10 15 20
Ca
con
cen
trat
ion
(M
)
Elpased time during the pulling phase (hr)
Modeled w/o carbonates
Modeled w/ carbonates
meas.
2.7E-04
3.1E-04
3.5E-04
3.9E-04
4.3E-04
0 5 10 15 20
Mg
con
cen
trat
ion
(M
)
Elpased time during the pulling phase (hr)
Modeled w/o carbonates
Modeled w/ carbonates
meas.
Ca Mg
1.0E-11
1.0E-10
1.0E-09
1.0E-08
1.0E-07
0 5 10 15 20
Pb
co
nce
ntr
atio
n (
M)
Elpased time during the pulling phase (hr)
Modeled w/o surface complexes
Modeled w/ surface complexes
meas.
Pb As
2) Adsorption/desorption
3.0E-07
5.0E-07
7.0E-07
9.0E-07
0 5 10 15 20
Ba
co
nce
ntr
atio
n (
M)
Elpased time during the pulling phase (hr)
Modeled w/o carbonates
Modeled w/ carbonates
meas.
7.0E-07
8.0E-07
9.0E-07
1.0E-06
1.1E-06
0 5 10 15 20
Sr c
on
cen
trat
ion
(M
)
Elpased time during the pulling phase (hr)
Modeled w/o carbonates
Modeled w/ carbonates
meas.
Sr Ba
1) Carbonate dissolution Mobilization of
trace metals
Br
Testing well
• Well was completed
with 2 PVC and
screened between
180 and 240 ft
• Depth of well: 240 ft
to surface
• Depth of water level:
90 ft to surface
12 field campaigns for groundwater sampling since August, 2008 On-site measurements: pH, temperature, alkalinity, water level
Lab analysis: Ag, Al, As, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Pb, Se, Zn, F-, Cl-, SO42-, Br-,
NO3-, PO4
3-, TOC, dissolved inorganic carbon (DIC), pH, alkalinity, VOC, 13C of DIC
Aquifer sediment
mineralogy analyzed
using XRD
Groundwater chemistry
dominated mainly by
silicate-mineral weathering
Testing well
Laboratory Scale
Field Scale
Ca
Mg
Ba
As
K Si
In order to interpret the batch experiment and the single-well push-pull
test in the field, we used a reactive-transport model for simulating
groundwater flow and solute transport coupled with geochemical
processes. The reactive-transport model consists of two sub-models: a
model of groundwater flow and solute transport, and a geochemical
model.
Groundwater-flow and solute-transport model: radius of the model domain is 25
m, and thickness is 7 m. The top and bottom boundaries are assumed to be no-
flow boundaries. Groundwater was injected into the aquifer through the testing
well during the injection phase and pumped out during the pulling phase.
Geochemical model: simulates geochemical processes (aqueous complexation,
mineral precipitation/dissolution, cation exchange reactions, and
adsorption/desorption) in the batch experiment and the push-pull test.
(mo
l/L
)
Elapsed
Elapsed Elapsed
Elapsed Elapsed Elapsed Elapsed
Elapsed Elapsed Elapsed Elapsed