Field results from a Controlled Release of Dissolved CO ... · Robert C. Trautz Sr. Project Manager...

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)


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


Geologic Characterization (Installed six wells)

154 to 179 ft (46.9 to 54.6 m)


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


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)


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)


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


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


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)


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


Typical Cation Response — Rapid Concentration Increase followed by Decline and Leveling Off

Fe


Major Cation Responses (+Chloride) Observed at MW-3


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


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


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


Together…Shaping the Future of Electricity

Field results from a Controlled Release of Dissolved CO ... · Robert C. Trautz Sr. Project Manager...

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