Post on 23-Mar-2020
Robert C. Trautz Sr. Project Manager
IEA-GHG Environmental Impacts of CO2 Storage Workshop Bozeman, Montana
July 17, 2012
Field results from a Controlled Release of Dissolved CO2 into Dilute Groundwater
2 © 2012 Electric Power Research Institute, Inc. All rights reserved.
Overview
• Objective: Investigate potential CO2–induced mobilization of metals using a controlled release of dissolved CO2 into groundwater
• Phased Study – Phase 1: Site Characterization (2010-2011) – Phase 2: Injection (2011-2012) – Phase 3: Post-injection monitoring, site closure and final
reporting (2012-2013) • EPRI project hosted by Southern Company at Plant Daniel
(MS) – Key participant – Berkeley Lab geochemistry group – Collaboration with five National Laboratories (LBNL,
LANL, PNNL, NETL, LLNL) independently funded by the National Risk Assessment Program (NRAP)
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Test Configuration — Doublet Provides Hydraulic Control of the Dissolved CO2 Plume
PW-1 IW-1
CO2
DissolvedCO2
Pum
p Inje
ct
Monitor
Carbonated Groundwater Groundwater
Doublet — Plan View
Doublet — Side View
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Geologic Characterization (Installed six wells)
154 to 179 ft (46.9 to 54.6 m)
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Hydrologic Characterization (Flat Hydraulic Gradient, homogenous sand)
Na-HCO3 Type Groundwater
0.1 1. 10. 100. 1000. 1.0E+40.001
0.01
0.1
1.
Time (min)
Dis
plac
emen
t (ft)
Obs. WellsTW-1
Aquifer ModelConfined
SolutionTheis
ParametersT = 816.1 ft2/dayS = 0.0001694Kz/Kr = 0.1b = 20. ft
TW-127 hr data5 gpm blended rateTheis solutionT = 816.1 ft2/dS = 0.0001694
0.1 1. 10. 100. 1000. 1.0E+40.001
0.01
0.1
1.
Time (min)
Dis
plac
emen
t (ft)
Obs. WellsTW-1
Aquifer ModelConfined
SolutionTheis
ParametersT = 816.1 ft2/dayS = 0.0001694Kz/Kr = 0.1b = 20. ft
TW-127 hr data5 gpm blended rateTheis solutionT = 816.1 ft2/dS = 0.0001694
Homogenous Fine Sand
27 hr. pumping well test
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Mineral properties •XRD •SEM & optical microscopy Sediment Metal-Associations •Synchrotron techniques •Selective extractions including
microwave digestion Other measurements •Acid titrations to measure pH
buffer capacity (very little capacity) •Soil Carbon analysis (sand <0.1%,
black laminations 2.4%)
Sediment Characterization (Identified Black Laminations within the Sand)
Synchrotron Image: Black laminations has metal-binding sulfur groups (organic thiols
& pyrites)
Black laminated sediments contain arsenic and lead associated with pyrite
Bulk sand, 53-57 m (160-171 ft)
Black laminations, 56 m (167 ft)
7 © 2012 Electric Power Research Institute, Inc. All rights reserved.
0
10
20
30
40
��Target Formation �� Black Lamination
Arsenic (ug/l)
EPA MCL
0
20
40
60
80
��Target Formation �� Black Lamination
Lead (ug/l)
EPA MCL
0
15000
30000
45000
60000
75000
90000
�Target Formation � Black Lamination
Calcium (ug/l)
0
5000
10000
15000
20000
25000
30000
35000
�Target Formation � Black Lamination
Iron (ug/l)
8 © 2012 Electric Power Research Institute, Inc. All rights reserved.
Constructed a Closed-Loop Dissolved CO2 Injection System
TemperatureFlow
Pressure Filtration
pH
Temperature
PressureCarbonation
• Closed loop system prevents contact with oxygen (redox)
• Tank and evaporator supply CO2 at constant pressure and temperature
• Carbonation unit containing a contact membrane infuses CO2 into the groundwater at reservoir pressure
• Groundwater is slightly undersaturated with respect to CO2 (pH ~ 5)
• Booster pump injects dissolved CO2 at 1.5 gpm back into sand
Groundwater carbonation unit used in the controlled release experiment
9 © 2012 Electric Power Research Institute, Inc. All rights reserved.
Sampling Groundwater Quality (Baseline and Operational Monitoring)
• Innovative sampling technique for dissolved gases
• Baseline sampling (12 mos) • Operational sampling (once every
2 days – 1 mos) • Parameters
– Field parameters (e.g., pH, ORP, DO, Temperature, Fe2+, and sulfides)
– Trace metals (e.g., As, Pb, Cr) by ICP-MS
– Major cations (e.g., Ca, Mg, Na, K) – Major anions (e.g., Cl, HCO3, SO4)
– Dissolved gases (e.g., CO2, methane, ethane …)
– Isotopes (e.g., δ13C, δ18O, δD, 87Sr/86Sr)
• In situ measurements (T, pH, EC, ORP)
Copper Sampling
Tubes
Flow cell Pressure gauge
Backpressure regulator
Groundwater is pumped out of the well against a backpressure regulator. This minimizes CO2 degassing
during sample collection, which can change sample pH and dissolved ion concentrations
10 © 2012 Electric Power Research Institute, Inc. All rights reserved.
Dissolved CO2 Breakthrough Occurred Within 10-157 Days of Start of Injection
Site plan showing well locations: BG=background,
IW=injection, MW=monitoring, PW=pumping Injection Pumping
In situ pH response observed at four monitoring wells
(Aug-2011 to June 2012)
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ERT Cross-well Monitoring
Resistivity [Ohm-m] Difference from Baseline [Ohm-m]
Baseline between wells MW1 (left) and MW4 (right)
October 28th: no significant variation from baseline except where high-contrast between
layers causes artifacts
January 30th: Definite decrease in resistivity as noted within
“red circle”
January 23rd: start to see very small change in top of MW1
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Typical Cation Response — Rapid Concentration Increase followed by Decline and Leveling Off
Fe
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Major Cation Responses (+Chloride) Observed at MW-3
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Intra-well Statistical Comparison* for MW-3 and Comparison to Environmental Protection Agency Regulated Metals
Parameter Unit
Static and Dynamic Baseline
CO2 Injection and Post-Injection
MDL EPA MCL
1 Sign
ifica
nt?
Abo
ve M
CL
?
Min. Max. Min. Max.
Arsenic mg/L <0.0013 <0.0013 <0.0013 <0.0013 0.0013 0.01 No No
Barium mg/L 0.055 0.11 0.062 0.48 0.0013 2 Yes No
Beryllium mg/L <0.00025 <0.00025 <0.00025 0.00072 0.00025 0.004 Yes No
Chromium mg/L <0.0025 0.007 <0.0025 0.013 0.0025 0.1 Yes No
Copper mg/L <0.0011 0.002 <0.0011 0.001 0.0011 1.3 No No
Fluoride mg/L 0.18 0.58 0.051 0.43 0.0035 4 No No
Mercury mg/L <0.00007 0.00017 <0.00007 0.00023 0.00007 0.002 Yes No
Lead mg/L <0.0002 0.0009 <0.0002 <0.0002 0.0002 0.015 No No
Antimony mg/L <0.0023 <0.0023 <0.0023 0.003 0.0023 0.006 Yes No
Selenium mg/L <0.001 <0.001 <0.001 <0.001 0.001 0.05 No No
Thallium mg/L <0.0005 <0.0005 <0.0005 <0.0005 0.0005 0.002 No No
*Nonparametric prediction limit test
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Summary (based on MW-3)
• Lab characterization of sediments indicates that trace metals are present
• Majority of trace metals (e.g., As, Cu, Pb) remained below their respective method detection levels – Unknown whether they
are increasing or decreasing
Typical response for several non-detect trace metals (e.g., As, Cd, Cu, Pb, Se, Th)
showing occasional outliers
Pre-injection Outliers
Lead Concentration vs. Time
Injection Starts
Detection Limit
None of the constituents exceeded primary drinking water standards for US
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Summary
• Sorption/desorption processes are likely mechanisms responsible for rapid increase-decrease in concentrations
• But … elevated concentrations of several constituents were observed at MW-1 and MW-2 wells implying that: – Dissolution processes are starting to dominate later in time; and/or – The plume front become comes wider as more metals desorb and
begin to accumulate and move with the front
• ES&T Special Issue on CO2 Sequestration (2013) Effect of Dissolved CO2 on a Shallow Groundwater System—
A Controlled Release Field Experiment Robert C. Trautz, John D. Pugh, Charuleka Varadharajan, Liange
Zheng, Marco Bianchi, Peter S. Nico, Nicolas F. Spycher, Dennis L. Newell, Richard A. Esposito, Yuxin Wu, Baptiste Dafflon, Susan S. Hubbard, and Jens T. Birkholzer
17 © 2012 Electric Power Research Institute, Inc. All rights reserved.
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