surface monitoring for geologic carbon sequestration (2011, licor)

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Surace Monitoring orGeologic Carbon SequestrationVol. 2: Monitoring Methods, Instrumentation, and Case Studies


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It is well known that carbon dioxide (CO2) is a green-

house gas that contributes to climate change. CO2

is emitted into the atmosphere whenever ossil uels

are burned. The largest sources o man-made CO2

emissions are coal- and gas-fred power plants and

automotive transportation. Carbon Capture and

Geologic Sequestration has been identifed as a way

to mitigate CO2 emissions to the atmosphere.

Geologic ormations suitable or underground CO2 storage have beenidentied around the world. ypically, these ormations are depletedoil and gas reservoirs, coal beds, and deep saline aquiers. Te potentialglobal capacity or geologic storage o CO2 is large and could cor-respond to hundreds o years o anthropogenic CO2 emissions. Teability o many o these reservoirs to store natural gas and naturally-

occurring CO2 over millions o years helps to prove the credibility odeep underground storage.

However leak-tight an underground storage ormation may seem, itremains the responsibility o the project owner to prove no leakage oCO2 is occurring. While ambient levels o CO2 are harmless, concen-trated CO2 can be atal to plants and animals, including humans. Tepublic needs to be assured that no leaks exist that would endanger theirhealth or negate the benets o the carbon storage project. Suracemonitoring above geologic storage ormations is eective proo o stor-age ormation integrity.

LI-COR Biosciences published Volume 1 o Surace Monitoring orGeologic Carbon Sequestration in 2009; this updated edition brieydescribes two methods or geologic sequestration surace monitoring,as well as the challenges associated with each method. Also describedis instrumentation available rom LI-COR Biosciences that has beenused to eectively monitor or CO2 leaks rom geologic storage orma-tions. At the end o this note we present two new case studies o suracemonitoring projects already underway that use the LI-8100/LI-8100AAutomated Soil CO2 Flux System and/or LI-7500/A Open Path CO2/H2O Analyzer or Carbon Capture and Storage surace monitoring.

1 - Introduction

Introduction


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Instrumentation or

Surace MonitoringTe LI-8100 was introduced in 2003 to address the need ora robust, dedicated system or measuring soil CO2 ux over awide variety o environmental conditions. Drawing upon more

than a decade o experience in making soil CO2 ux measure-ments, LI-COR designed a system that addresses both temporaland spatial variability with integrated survey and long-termchamber designs, as well as a multiplexer (LI-8150) that al lowslong-term measurements with as many as 16 chambers. Forconducting measurements over a number o locations, 10 cm(8100-102) and 20 cm (8100-103) survey chambers allow rapid,repeatable measurements to obtain accurate determination ospatial variability. Long-term diel measurements can be auto-mated at a single location or weeks or months at a time usingthe 8100-104 or 8100-104C long-term chambers, which, when

combined with the LI-8150 Multiplexer, provides assessment oboth temporal and spatial variability. Innovations like cham-ber drive mechanisms that automatically move the chamberaway rom the soil environment being measured, a pressurevent design that allows chamber pressure to track the ambientpressure under windy or calm conditions, perorated baseplatesto minimize perturbations to the soil enviroment, and cham-bers that close automatically to eliminate variations caused bymanual chamber placement ensure that soil CO2 ux measure-ments are accurate and repeatable. In 2010, LI-COR releasedthe LI-8100A, which expanded the LI-8100s capabilities by

extending the CO2 measurement range to 20,000 ppm, allow-ing or soil CO2 ux measurements in high CO2 environments.Te LI-8100A also added Ethernet connectivity or two-waycommunication with networked computers, and remote setup,data collection, and diagnostics by simply logging onto anyLI-8100A connected to a local network. Setup and operationare also possible with many Wi-Fi enabled devices using a Win-dows Mobile application.

For measuring CO2 uxes above suraces using micrometeo-rological methods such as Eddy Covariance, LI-COR oers

the LI-7500A Open Path CO2/H2O Analyzer, which eaturesthe ast response times and low power requirements needed tomake ux measurements between vegetation and the atmo-sphere, primarily on eld station towers. In addition, a newEnclosed CO2/H2O Analyzer, the LI-7200, is also available,which combines the advantages o both open and closed pathanalyzers. Te LI-7200 is based on the design o the LI-7500A,uses low power, and can be mounted in the same manner asthe LI-7500A; however, the LI-7200 encloses the optical pathby using a short intake tube, which eliminates CO2 and H2Olosses during rain events.

Monitoring, Verifcation,

and AccountingTe purpose o Monitoring, Verication, and Accounting(MVA) is to provide an accurate accounting o stored CO2 anda high level o condence that the CO2 remains sequestered

permanently. A successul eort enables sequestration projectdevelopers to ensure human health and saety and preventdamage to the host ecosystem. MVA requires an entire host otools to eectively understand the CO2 movement within thestorage ormation. One such tool is understanding and quanti-ying potential surace leakage sites. An active surace monitor-ing campaign helps to quantiy natural ecosystem backgrounduxes, which makes understanding and quantiying leakageareas easier. Surace monitoring is also an eective way to con-vince the public that leaks are not occurring.

Surace MonitoringMethods or soil CO2 ux measurement

Tere are two primary methods to quantiy the rate o CO2release rom the ground to the atmosphere. One method ischamber-based, which includes an open-chamber and closed-chamber method. Te other method is micrometeorological,which includes the Eddy Covariance method, Bowen-Ratioenergy balance method and aerodynamic method (Verma [1]).

Chamber-based soil CO2

ux measurement

Te closed-chamber method is the most common approachused to estimate the uxes o CO2 (Fc, mol m

-2s-1) and othertrace gases at the soil surace. It is widely used in carbon cycleresearch as well as other environmental research areas (Normanet al. [2];Davidson et al. [3]). In this method, a small portiono air is circulated rom a chamber to an inrared gas analyzer(IRGA) and then sent back to the chamber. Fc is estimated withEq. 1 chamber volume, soil surace area, air temperature, atmo-spheric pressure, and the rate o CO2 concentration increaseinside the chamber (dCc/dt, mol mol

-1s-1) which has been on

the soil surace or a short period o time.

WherePis the atmospheric pressure (Pa), V (m3) is the totalsystem volume, including the volume o the chamber, the pumpand tubing in the measurement loop,R is the gas constant(8.314 Pa m3 K-1 mol-1), Tis the absolute temperature (K), andS(m2) is the soil area covered by the chamber.

Instrumentation or Surace Monitoring - 2

(1)FPV

RTS

dC

dtc

c=


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ON/OFF

AutomatedSoil

CO2Flux

System

ON/OFF

POWERIR

GARE

ADY

ACTIV

E

LOWBA

TTER

Y

READY

ON/OFF

ON/OFF

DiaphragmPump

To Chamber

From ChamberFilter

Analyzer

Bench

Analyzer Control Unit

20 cm Survey

Chamber

Figure 1. Schematic diagram o the measurement ow path or the

Automated Soil CO2 Flux System (LI-8100A, LI-COR Biosciences,

Lincoln, NE). A 20-cm survey chamber is shown with the control

unit. The system can also support measurements with a 10-cm

survey chamber and 20-cm Long-term Chambers.

Many custom-made closed systems have been described in theliterature (e.g. Savage and Davidson [4];Irvine and Law [5])and commercially available systems can also be used. Figure 1presents a schematic diagram or the LI-8100A Automated Soil

CO2 Flux System showing the ow path, a 20-cm survey cham-ber and analyzer control unit, and optical bench. In additionto carbon cycle research, the closed chamber method has beenused in agronomy, soil science, and ecological studies.

Instrumentation confguration

Soil CO2 production depends strongly on many environmental(soil temperature, soil moisture, organic content) and biologi-cal actors (above ground canopy size, growth activity, etc). Asa result, soil CO2 ux oen shows strong temporal and spatial

variations, which means that the ux can change signicantlyover time and location at a research site. o address this issue,LI-COR Biosciences has developed survey chambers, long-termchambers, and a multiplexer or the LI-8100A System. wosurvey chambers are available, 8100-102 (10 cm) and 8100-103 (20 cm). Both chambers operate with a unique pneumaticsystem that contracts and expands a bellows to raise and lowerthe chamber over the soil collar. Tis automation eliminates soildisturbances that would otherwise occur with mechanical in-stallation and removal o the chamber rom the collar betweensampling repetitions. Te pneumatic bellows system raises the

chamber between repetitions to allow or equilibration withambient CO2 concentrations beore gently lowering again toperorm another repetition.

LI-COR oers two long-term chambers (8100-104, 8100-104C) to make long-term unattended measurements o soilCO2 ux. Te 8100-104/C chambers have a li-and-rotatedrive mechanism that rotates the chamber to six congurableopen positions. During the non-measurement period, bothlong-term chambers park away rom the collar areas to ensurethat disturbance to the soil environmental conditions inside thecollar is kept to a minimum.

All our chambers close gently onto the collar to minimizepressure pulsations that can change the soil CO2 concentration,which in turn aects the soil CO2 ux measurement.

o satisy both temporal and spatial resolution requirementsor monitoring CO2 ux, LI-COR Biosciences has developedthe LI-8150 Multiplexer, which can allow up to 16 chambers tobe connected to provide adequate spatial coverage. Te systems

automation enables long-term, unattended measurement odiurnal and seasonal ux at 16 dierent locations over an areawith a diameter o 30 m.

Requirements or an accurate soil CO2 uxmeasurement

Te concept o chamber-based soil CO2 ux measurementscan at rst seem quite simple. However, many considerationsmust be taken into account in the process o instrument designand making the measurements in order to have accurate uxdata. As stated above, soil CO2 production strongly depends on

many environmental conditions. Also, soil CO2 ux is a physi-cal process driven primarily by the CO2 concentration diu-sion gradient between the upper soil layers and the atmospherenear the soil surace. Te undamental challenge or makingaccurate soil CO2 ux measurements is that the deploymento chambers must minimize disturbance to environmentalconditions that impact CO2 production and transport insidethe soil prole. Te our most undamental considerations oran accurate measurement are (1) maintain pressure equilibriumbetween inside a chamber and the ambient air, (2) ensure goodmixing, (3) control altered CO2 diusion gradients, and (4)minimize the disturbances to environmental conditions. Belowwe will discuss the impact o each o these considerations onthe measurement and how we careully address them.

(1). Maintain pressure equilibrium betweeninside a chamber and the ambient air.

Pressure equilibrium between the inside o a soil CO2 uxchamber and the surrounding air outside the chamber must bemaintained during the measurement i measured ux is to accu-rately represent the rate occurring naturally outside the cham-

ber. A simple open vent tube connecting to the chamber hasoen been used or the pressure equilibrium (e.g.Hutchinsonand Mosier[6];Davidson et al. [3]). Tis approach, however, iseective only under calm conditions. Under windy conditions,negative chamber pressure excursion will occur as wind blowsover the vent tubes external open end, due to the Venturi eectTis excursion will cause a mass ow o CO2-rich air rom thesoil into the chamber, leading to a signicant overestimation osoil CO2 ux. In act, some researchers (e.g. Conen and Smith[7]) recommended eliminating the vent tube aer recognizingthe potential problem rom the Venturi eect.

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Scientists and engineers at LI-COR Biosciences have developeda patent-pending vent design or the chambers. Te new venthas a tapered cross section as shown in Figure 2. Conservationo mass requires that the average air ow rate drops as the airenters the vent. According to Bernoulli s equation, as the airow rate decreases, a major portion o dynamic pressure is con-verted to static pressure, raising the static pressure with whichthe chamber equilibrates. Tis design is radially symmetric to

eliminate wind-direction sensitivity. Data rom eld experi-ments on dierential pressure measurements between insidethe chamber and the outside ambient air show that chambersequipped with our newly designed vent always have internalchamber pressure equal to outside the chamber under bothcalm and windy conditions. Our new vent virtually eliminatesthe Venturi eect. For more details, see our published journalpaper (Xu et al. [8]).

UT UV

ToChamber

h2 h1

Figure 2. Cross-section view o the new vent design (patent pend-

ing). UT is the wind speed at the height o the vent. U V is the wind

speed inside the vent near the vent tubing. h1 and h2 is the edge and

the central distance between the upper- and the lower-hal o the

vent. UV depends on the ratio o h1 to h2.

(2). Ensure good mixing.

Because only a small portion o the chamber air is sent to theinrared gas analyzer (IRGA) to determine the increase rateo chamber CO2 concentration (dCc/dt), good mixing insidethe chamber is essential. A mixing an has been used in manycustom-made soil CO2 ux systems to achieve good mixing,but using a mixing an inside a chamber can also cause distur-bances in the pressure equilibrium. o eliminate any potentialchamber pressure perturbation, a mixing an is not used onLI-8100A chambers. Good mixing is achieved through bothoptimal chamber geometry (bowl shape or 8100-103 and -104

chambers) and a mixing maniold (8100-102 chamber).

(3). Control altered CO2 diusion gradients.

Soil CO2 ux is driven primarily by the CO2 diusion gradi-ent across the soil surace. With the closed-chamber techniqueor estimating ux, the chamber headspace CO2 concentra-tion (Cc) must be allowed to rise in order to obtain the rate ochange in Cc (dCc/dt). However, raisingCc will reduce the CO2diusion gradient across the soil surace inside the chamber,leading to an underestimation o the ux. o overcome this, a

new exponential unction is derived to t the time series oCc,taking the eect o water vapor dilution into account (Eq. 2).With the initial slope ( ) o the tted unction (Eq.3), the ux is then estimated at the time o chamber closing,when Cc is close to the ambient level (Fig. 3).

(2)

(3)where Ccis the chamber CO2 concentration corrected orwater vapor dilution (mol mol-1), Cs is the CO2 concentra-tion in the soil surace layer communicating with the chamber(mol mol-1), also corrected or water vapor dilution, anda is arate constant (s-1).

Comparison oFc measurements between this new approachand an earlier draw-down method (Norman, et al . [2]; Welles etal. [9]) yielded an excellent agreement, suggesting that both ap-proaches are eective in minimizing the impact o altered CO2

diusion gradients on the ux measurement. From the litera-ture, a linear regression oen has been used on the time serieso chamber CO2 data to determineFc. Our experimental datashow that the underestimation oFc rom the linear approachwas systematic and signicant, even though the linear regres-sion sometimes gave a very high value or the regression coe-cient (Fig. 3). Furthermore, the underestimation was greateror porous soils that had high conductance-to-gas transport.Tereore, we do not recommend using the linear regression onthe time series o chamber CO2 data to determine the dCc/dt.

(4). Minimize the disturbances toenvironmental conditions.

For a long-term soil CO2 ux measurement, it is critical to keepthe environmental conditions inside the collar as close to thenatural conditions as possible. Te impact o installation othe long-term chamber on radiation balance, wind eld, andprecipitation interception should be minimized. Tis issue wasaddressed careully when we designed the long-term chambers.Both chambers are parked away rom the collar when they arenot in the measurement mode. Te baseplate o the two long-term chambers is also perorated to minimize perturbation tothe soil environment around the collar.

All our chambers close and open automatically and slowly.Tis eliminates the possibility o pushing resh ambient air intothe soil or removing soil air during the chamber closing/open-ing. emperature artiacts are minimized by careul consider-ation o chamber materials and coatings.

C C C C ec s c sat

=+

[ ] ( )0dC

dt

c = a[Cs - Cc(0)]e

-at

dC dt c t/ =0

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Figure 3. Illustration o the exponential approach implemented in

LI-8100A Automated Soil CO2 Flux System. An example o time

series o chamber CO2 concentration and a comparison o the

slopes rom the linear regression and the exponential regression.

The chamber touched down at time t = 0. The observation lengthwas 120 s and the deadband was set to 20 s. A deadband is required

or the chamber to reach steady mixing. CO2 data rom 21 to 120 s

were used to ft the linear equation and the exponential equation

(Eq. 2).

Example o soil CO2 ux measurement over asoybean feld in Nebraska

Fig. 4 shows an example o diurnal soil CO2 ux rom a soy-bean eld at the University o Nebraska-Lincoln AgriculturalExperimental Station near Mead, NE. Te dataset was obtained

in the middle o the growing season ( July 9 to 19, 2006). Teux value and soil temperature at 5 cm depth were averagedrom 16 measurements at dierent locations with an LI-8100multiplexed system. Te soil CO2 ux ranged rom 2 to 7 molm-2s-1. Te soil CO2 ux shows a strong diurnal pattern andclosely ollows the soil temperature variations; this is becausemicrobial respiration increases exponentially with temperature.Tis ux range o 2 to 7 mol m-2s-1 was comparable with othersoil CO2 ux data published in the literature obtained romsimilar agricultural elds in the middle o the growing season.Normally, the soil CO2 ux rom natural ecosystems can vary

rom less than 1 mol m-2

s-1

, to around 10 mol m-2

s-1

, depend-ing on the soil temperature, moisture, soil organic matter, plantcanopy size, growing season, etc.

Day of Year 2006190 192 194 196 198 200

Fc

(molm

-2s-1)

0

2

4

6

8

10

Tsoil

(oC)

15

20

25

30

35

Fc

Tsoil

Figure 4. Example o diurnal soil CO2 ux (Fc) measured with an

LI-8100 sixteen chamber multiplexed soil CO2 ux system rom a

soybean feld at University o Nebraska Lincoln Agricultural

Experimental Station at Mead, Nebraska. Soil temperature at a

depth o 5 cm (Tsoil) is also shown.

Micrometeorology-based

Flux MeasurementsPerhaps the most direct method available or measuring CO2uxes above a surace is the Eddy Covariance method, whichwas rst proposed bySwinbank [10]. Tis method relies onmeasurements o the deviation (or so-called perturbation) overtical wind velocity (w) and o an associated scalar rom theirmean values. aking CO2 ux (Fc) measurement as an examplevertical wind velocity perturbation (w) and air CO2 density(CO2) can be calculated rom high requency (usually 10 Hz)measurements o vertical wind velocity and air density accord-ing to:

w w w= (4)

CO CO CO2 2 2= (5)

Te over bar denotes time averaged values. Fc over a surace canbe determined as:

F w COc = 2 (6

Tis method relies on measurements o the uctuating com-ponents o vertical wind and CO2 density in the constant uxregion o the surace-boundary layer (Monteith and Unsworth[11]).

Although it was proposed in the early 1950s (Swinbank [10]),this method was used over crop elds and other natural ecosys-tems only aer development o ast-response sensors andcomputer data-acquisition equipment (Baldocchi et al. [12]).Most recently, this method has been widely used or themeasurement o CO2 ux between natural vegetation and theatmosphere in the network o eld stations or the research oglobal carbon budget, including AmeriFlux, CarboEurope,AsiaFlux, and the Canadian Carbon Program (Baldocchi et al.[13]; Verma et al. [14]).

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Sensors or Eddy Covari-ance measurement arenormally mounted on atower. Te response time orsonic and gas analyzers mustbe 10 Hz or aster becausespectrum analysis showsthat the turbulent transporto any scalar in the suraceboundary layer rom eddysizes range rom 0.001 to 10Hz. Tis method measuresthe average CO2 ux over anintegrated area as seen by

the sonic anemometer andthe gas analyzer. As a rule othumb, this integrated areaextends to a distance about100 times the height o thesensors to the up-winddirection.

Te requirements or making an Eddy Covariance CO2 uxmeasurement are (1) ast response o both the sonic anemom-eter and gas analyzer; (2) density correction arising rom theuxes o sensible heat and latent heat ux (Webb-Pearman-Leuning correction [15]), and (3) a relatively large, at eld site.For more inormation on how to make the Eddy CovarianceCO2 ux measurement, printed and/or electronic copies o ahandbook entitled A Brie Practical Guide to Eddy Covariance

Flux Measurements, authored by LI-COR scientists, is availableat: www.licor.com/ec-analyzers

LI-COR also oers an introductory course with hands-ontraining on site in Lincoln, NE. More inormation and registra-tion orms are available here:http://www.licor.com/ec-training.

Designed by LI-COR scientists, the course provides inorma-tion on the general principles, requirements, applications, andprocessing steps o the Eddy Covariance method.

Reerences

1. S.B. Verma. (1990). Micrometeorological methods or measur-

ing surace uxes o mass and energy. Remote Sensing Reviews

5(1), 99 -115.

2. J.M. Norman, R. Garcia and S.B. Verma. (1992). Soil surace

CO2 uxes and the carbon budget o a grassland. J. Geophys.

Res., 97, 18,845-18,853.

3. E.A Davidson, K. Savage, L.V. Verchot, and R. Navarro. (2002).

Minimizing artiacts and biases in chamber-based measurements

o soil respiration. Agri. For. Meteorol. 113:21-37.

4. K.E. Savage and E.A. Davidson. (2003). A comparison o

manual and automated systems or soil CO2 measurements:

trade-os between spatial and temporal resolution. J. Exp. Bot.,

54, 891-899.

5. J. Irvine and B. Law. (2002). Contrasting Soil Respiration in

young- and old-growth ponderosa pine orests. Global Change

Biology. 8, 1183-1194.

6. G.L. Hutchinson, A.R. Mosier. (1981). Improved soil covermethod or feld measurement o nitrous oxide uxes. Soil Sci.

Soc. Am. J. 45:311-316.

7. F. Conen, and K.A. Smith. (1998). A re-examination o closed

ux chamber methods or the measurement o trace gas emis-

sion rom soils to the atmosphere. Eur. J. Soil Sci. 49:701-707

8. L.K. Xu, M.D. Furtaw, R.A. Madsen, R.L. Garcia, D.J. An-

derson and D.K. McDermitt. (2006). On maintaining pressure

equilibrium between a soil CO2 ux chamber and ambient air. J.

Geophys. Res. Atm. 111, D08S10, doi:10.1029/2005JD006435.

9. J.M. Welles, T.H. Demetriades-Shah and D.K. McDermitt.

(2001). Considerations or measuring ground CO2 euxes with

chambers. Chemical Geol. 177, 3-13.

10. W.C Swinbank. (1951). The measurement o the vertical

transer o heat. J. Meteorol. 8, 135-145.

11. J.L. Monteith and M.H. Unsworth. (1990). Principals o Envi-

ronmental Physics. Edward Arnold, London

12. D.D. Baldocchi, B.B Hicks, and T.P. Meyers. (1988) Measuring

biosphereatmosphere exchanges o biologically related gases

with micrometeorological methods. Ecology, 69, 13311340.

13. D.D. Baldocchi, E. Falge, and L.Gu et al. (2001). Fluxnet: anew tool to study the temporal and spatial variability o ecosys-

tem-scale carbon dioxide, water vapor and energy ux densities.

Bull. Am. Meteorol. Soc. 82, 24152434.

14. S.B. Verma, A. Dobermann and K.G. Cassman et al. (2005)

Annual CO2 exchange in irrigated and rained maize-based agro-

ecosystems. Agricultural and Forest Meteorology, 131, 7796.

15. E.K. Webb, G.I. Pearman and R. Leuning. (1980) Correction o

ux measurements or density eects due to heat and water va-

pour transer. Quarterly Journal o Royal Meteorological Society,

106, 85100.

Figure 5. An example o the

instrumentation setup or an

Eddy Covariance ux measure-

ment. Picture shows a 3-D sonic

anemometer (Gill Windmaster,

Gill Instruments Ltd., Lymington,

England) and an Open Path CO2/H2O analyzer (LI-7500A, LI-COR

Biosciences, Lincoln, NE).

Micrometeorology-based Flux Measurements - 6


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In terms o Carbon Capture and Storage, a

universal regulatory ramework needs to be

in place that requires uniormity in all aspects

o pre-injection, injection, and post-injection

activities such as Surace Monitoring to

ensure the CO2 stays in place. Currently

there are numerous studies and pilot projects

underway that are helping to determine the

best methods or monitoring CO2 release rom

the surace both pre- and post-injection.

LI-COR Biosciences has specialized in ambient CO2 moni-toring or the last 25 years. Our open and closed path CO2

analyzers are used worldwide in many dierent applications.In terms o CCS technology, the LI-8100A Automated SoilCO2 Flux System can be used to monitor surace leaks andnatural background uxes in multiple locations. LI-CORalso oers the LI-7500A Open Path CO2/H2O Analyzer thatis commonly used in Eddy Covariance measurements to de-termine the vertical CO2 ux over a relatively large area. TeEddy Covariance method is an eective way to monitor largeareas where CO2 may escape rom the subsurace. Belowwe will discuss two o the many surace monitoring projectsalready underway that involve using the LI-8100A and/or

LI-7500A or Carbon Capture and Storage.

Case Study 1:

Midwest Geological SequestrationConsortium Illinois Basin Decatur Project

Te Midwest Geological Sequestration Consortium (MGSC)in cooperation with Archer Daniels Midland (ADM) Com-pany, is conducting a large-scale carbon sequestration dem-onstration project in Decatur, Illinois. In 2011, the Illinois

Basin - Decatur Project (IBDP) will begin injecting 1,000tonnes/day o carbon dioxide or three years into the MountSimon Sandstone at a depth o approximately 2,100 meters.Te project seeks to demonstrate the ability o a deep salineormation to saely store one million tonnes o CO2 in theIllinois Basin, a 155,000 square-kilometer subsurace geologiceature which occurs in Illinois, southwestern Indiana, andwestern Kentucky.

MGSC is conducting an extensive monitoring, verica-tion and accounting program in the deep subsurace and

near-surace environments. Near-surace monitoring equip-ment includes the LI-COR LI-7500 Open Path CO2/H2Oanalyzer, a portable LI-COR LI-8100 Automated Soil CO2Flux System, and a multiplexed LI-8100/LI-8150 System.Tis instrumentation is being used to collect baseline data tocharacterize net CO2 uxes and soil CO2 uxes and will beused throughout the project to monitor or potential CO2leakage signals.

Figure 1. Measuring soil CO2 uxes at the IBDP site using the

LI-COR LI-8100.

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A network o 118 soil ux rings has been developed at the proj-ect site. Soil CO2 uxes have been monitored weekly since June2009 using a single-chamber LI-8100 (Figure 1) to assess spatialand temporal variability and to develop a long-term baselinerecord.

A unique approach has been taken at the IBDP site to evaluatemultiple types o ring installations and determine which type

would be the most eective in monitoring or potential CO2leakage. Te three installation techniques being evaluated are:1) bare-shallow, 2) bare-deep, and 3) natural-shallow rings.Natural-shallow rings are minimally maintained with the natu-ral grassy vegetation le undisturbed (Figure 2).

Figure 2. Natural (let) and bare (right) soil rings used to determine

soil CO2 uxes at the IBDP site.

Tese rings are used to determine the natural soil CO2 ux.In contrast, a 60-cm diameter dead zone in and around eachbare-shallow and bare-deep ring location is maintained bythe periodic application o herbicide and manual removal oplant debris to minimize plant and root respiration in andnear the rings (Figure 2). Natural-shallow and bare-shallowrings were driven about 8 cm into the ground. Bare-deep rings

were driven about 46 cm into the ground and are intended tominimize shallow root zone inuences on ux measurements.As expected, the CO2 uxes were greatest in the natural shal-low rings and uxes in the bare-deep and shallow were similar(Figure 3). Te decline o uxes rom the bare-deep rings untilOctober 2010 is likely due to surcial vegetation dying aerinitial ring installation (Figure 3).

Figure 3. Soil CO2 uxes measured or three types o soil ring

installations at the IBDP site.

An LI-8100/LI-8150 Multiplexed System was recently deployedto provide a better temporal understanding o soil uxes at theproject site. Ports are being monitored at 30-minute intervalsto evaluate soil CO2 ux rom bare-shallow rings and natural-shallow rings. Tese data will be used to enhance interpreta-tion o the atmospheric CO2 ux data collected by an EddyCovariance system.

An Eddy Covariance (EC) system was deployed at the IBDPsite and used a LI-COR LI-7500 Open Path CO2/H2O Ana-lyzer mounted on top o a 10-meter tall tower to measure CO2and water vapor densities at a requency o 10 Hz. AtmosphericCO2 ux (Fc) measured rom July 2009 to May 2010 varied, asexpected, based on season (Figure 4). Fcvalues typically rangedrom -20 to 10 mol m-2s-1 in July-August 2009, declined to -10to 5 mol m-2s-1 in September 2009, and then were about0 mol m-2s-1 in November 2009-May 2010. Fcvalues remainedlow through spring (May), prior to signicant plant re-growth.When winds were blowing rom about 140 to 220 degrees, (1)

relatively high positive and negativeFcwere measured, and (2)a relatively large number oFcdata were lost due to lteringaccording to quality control criteria (Figure 4). PoorFcqualityassociated with these wind directions was likely due in part todisturbances in airow caused by the large waste water treat-ment structures located southeast o the EC tower.

Figure 4. Atmospheric CO2

ux (Fc) in relation to time and mean

horizontal wind direction measured by the Eddy Covariance tower

at the IBDP site.

For additional inormation see:

Locke, R.A. II, I.G. Krapac, J.L. Lewicki, and E. Curtis-Robin-son, 2010, Characterizing near-surace CO2 conditions beoreinjection Perspectives rom a CCS project in the IllinoisBasin, USA: Proceedings o the 10th International Conerenceon Greenhouse Gas echnologies, September 19-23, 2010, Am-sterdam, Te Netherlands: Energy Procedia, (in press).

Case Study No. 1 - 8


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Case Study 2:

SECARB Black Warrior Injection Test,Tuscaloosa County, Alabama

Te Black Warrior Basin has produced a large quantity o coal-bed methane and has the potential or considerable enhancedcoalbed methane production. Additionally, as bituminous coalcan adsorb approximately twice as much CO2 as methane at

reservoir pressure, the basin has signicant potential or CO2sequestration. A eld test is being conducted and has beendesigned to test reservoir conditions in the three primary targetcoal zones.* A number o monitoring activities are plannedor the site, including reservoir pressure monitoring in deepobservation wells, uid and pH monitoring in each coal bed,shallow groundwater quality monitoring, soil gas composi-tion, conservative tracers, and soil CO2 ux monitoring. A seto soil gas samples was collected and soil ux monitoring wasperormed at a control site located in Deerlick Creek to provideadditional background inormation on near surace conditions

in the region. Preliminary results indicate that a signicantvolume o CO2 is ound in the soil prole and carbon isotopicdata suggests that the CO2 is o bacterial origin. Soil CO2 uxdata was collected or nine months and indicated a high vari-ability among individual sites and through time. Te data showsignicant seasonal variations, with high ux rates during thewarm months associated with high soil activity and low uxrates during the winter months.

*Authors Note: As o the time o printing, this study was recently

completed.

IntroductionTe Black Warrior Basin has produced more than 2 c ocoalbed methane and the basin is conservatively estimated tohave the potential to store 5.9 c o CO2 in mature reservoirs.Based on this estimate, sequestration o CO2 would enhancecoalbed methane recovery, increasing reserves by more than 20percent [1]. A eld verication test program o carbon seques-tration in coal is being conducted in the Black Warrior Basinunder the auspices o the U.S. Department o Energys South-eastern Regional Carbon Sequestration Partnership (SECARB[2]). Te test is a small-scale, short-term test in an area wheretechnical easibility and commercial applicability are consideredto be high. Part o this project is to begin to develop and dem-onstrate technology to ensure the sae and permanent storage oCO2 in coal seams.

Project Design

Te project ocuses on the injection o about 1,000 tons o CO2into a mature coalbed methane well and a series o buildup andallo tests that will be monitored in the injection well and

a series o remote observation wells. Beore the injection test,one shallow water observation well and three deep observationwells will be drilled (Figures 1 and 2), and the injection wellsmechanical integrity will be tested to ensure that the test can beconducted saely. Coal samples rom cores in the deep wells wi llbe sent o to have adsorption isotherms or CH4 and CO2 run,or remaining gas in place analysis, and or proximate, ultimate,and petrographic analysis.

Figure 1. Schematic o planned locations or wells and surace

monitoring stations.

Figure 2. Schematic cross-section showing injection well and

observation wells.

Te injection test will begin with a pressure build-up test todetermine the time required or pressure stabilization o the

well and shut-in pressure. Te injection o the CO2 will occurin two stages at each o the three coal zones. Te rst stage othe injection consists o a 40-ton slug o CO2 injected to testthe injectivity and help estimate the pressure and rate to injecta larger amount o CO2. Aer pressure stabilizes in the coal,280 tons o CO2 will be injected to test longer term changes ininjectivity and pressure response. Once pressure stabilizes in theBlack Creek coal zone, the test will be repeated in the Mary Leecoal zone and then the Pratt coal zone [2, 8].

9 - Case Study No. 2


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Case Study No. 2 - 10

Monitoring Plan

A number o dierent methods are planned to monitor the in-jection and ensure the saety and eectiveness o this program.Surace soil monitoring activities consist o analysis o soil gascomposition and the measurement o soil gas ux. Te twenty-one monitoring stations (Figure 1) are arranged in a radial arrayat 50 m, 100 m, and 150 m rom the well. Soil gas samples were

taken in February 2007 at the control site and samples will betaken at the test site about three months beore and aer injec-tion. Samples are taken at a depth o 0, 0.3, 0.6, and 1.0 metersat each station and analyzed or gas composition (N2, O2,CO2, CH4, and light hydrocarbon concentrations) and isotopiccomposition o CO2. Soil CO2 ux monitoring at the controlsite began in May 2007 and continued through February 2008.Flux was measured at each o the 21 monitoring stations oncea month and weekly measurements were made at two stations.Flux monitoring will begin at the test site at least three monthsbeore injection and continue until site closure. Shallow ground

water and surace monitoring will provide important base-line and post-injection inormation to be used to evaluate theenvironmental saety o carbon sequestration and ECBM in theBlack Warrior Basin [8].

a.

0

2

4

6

8

10

12

0 5 10 15 20 25 30 35 40

Temperature (C)

Flux(mol/m

2/s)

b.

0

2

4

6

8

10

12

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7Moisture

Flux(mol/m

2/s)

Surace Monitoring - Soil CO2 Flux

Soil CO2 ux was measured using a LI-COR BiosciencesLI-8100 Automated Soil CO2 Flux System. Raw data werecollected in the eld, and ux rates were calculated using thesoware provided with the LI-8100. wo stations were sampledweekly; all 21 stations were sampled monthly. Soil temperatureand moisture were also measured at each station.

Soil ux is highly variable between stations and over time. Di-erences o 7.77 mol/m2/s between two sites on the same dayhave been measured and a dierence o 5.13 mol/m2/s romone week to the next at one site. While some stations are con-sistently below or above average, average ux rates var y wildly.Tere appears to be little correlation between soil temperatureor soil moisture and ux rates (Figure 3); however, there doesappear to be a seasonal uctuation (Figure 4). Seasonal varia-tions are to be expected as there is more soil microbial activityin the warm months than in the winter months. Te results osoil ux monitoring demonstrate that signicant CO

2

is issu-ing rom the soil prole at the control site, and comparison opre- and post-injection data at the test site will provide criticalinormation on soil gas emissions and the potential eects ocommercial sequestration and ECBM operations.

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

Center

N50

N100

N150

NE100

NE150

E50

E100

E150

SE100

SE150

S50

S100

S150

SW100

SW150

W50

W100

W150

NW100

NW150

May

June/July/Aug

Sept/Oct/Nov

Dec/Jan/Feb

Flux(mol/m2/s)

Figure 4. Graph o seasonal averages at each station.

Conclusions

A eld test is being conducted in the Black Warrior Basin thatis designed to test reservoir conditions in three Pottsville coalzones. A number o monitoring activities are planned or the

site including reservoir pressure monitoring in deep observa-tion wells, uid and pH monitoring in each coal bed, shallowgroundwater quality monitoring, soil gas composition, con-servative tracers, and soil CO2 ux monitoring. A signicantquantity o CO2 is ound in the soil naturally, and concentra-tions tend to increase with depth as the CO2 becomes depletedin 13C; this is consistent with bacterial activity in the soil pro-le. Less than one percent o the soil gas is light hydrocarbonsand methane and ethane dominate. Te hydrocarbon ractionhas a dryness index o about 0.98 and is wetter than the gas

Figure 3. Soil temperature, soil moisture levels, and ux rate.

a) Flux vs. soil temperature, and b) Flux vs. soil moisture.


12/16

11 - Case Study No. 2

produced in the adjacent well; the lower dryness o the soil-gashydrocarbons suggests that they are locally derived rom the soilprole and not the reservoir coal beds. Tere is a net movemento CO2 out o the soil year round at the control site between 0.2mol/m2/s and 10.35 mol/m2/s. Flux rate exhibits a seasonalvariation, with higher rates in the summer and lower rates inthe winter.

AcknowledgementsTis research was perormed under the auspices o the South-eastern Regional Carbon Sequestration Partnership was sup-ported by the U.S. Department o Energy through the South-ern States Energy Board and Virginia ech under Virginia echSubaward Agreement CR-19655-415227.

Reerences

1. Pashin, J. C., Carroll, R. E., Groshong, R. H., Jr., Raymond, D.

E., McIntyre, M. R., and Payton, J. W., 2004, Geologic screen-

ing criteria or sequestration o CO2 in coal: quantiying potential

o the Black Warrior coalbed methane airway, Alabama: Final

Technical Report, U.S. Department o Energy, National Technol-

ogy Laboratory, contract DE-FC26-00NT40927, 254 p.

2. Pashin, J. C., and Clark, P. E., 2006, SECARB feld test or CO 2

sequestration in coalbed methane reservoirs o the Black Warrior

Basin: Tuscaloosa, Alabama, University o Alabama, College o

Continuing Studies, 2006 International Coalbed Methane Sympo-

sium Proceedings, Paper 0620, 7 p.

3. Wang, Saiwei, Groshong, R. H., Jr., and Pashin, J. C., 1993,

Thin-skinned normal aults in Deerlick Creek coalbed-methane

feld, Black Warrior Basin, Alabama, in Pashin, J. C., ed., New

Perspectives on the Mississippian System o Alabama: Alabama

Geological Society 30th Annual Field Trip Guidebook, p. 69-78.

4. Pashin, J. C., Groshong, R. H., Jr., and Wang, Saiwei, 1995,

Thin-skinned structures inuence gas production in Alabama

coalbed methane felds: Tuscaloosa, Alabama, University o Ala-

bama, InterGas 95 Proceedings, p. 39-52.

5. Pashin, J. C., and Groshong, R. H., Jr., 1998, Structural control

o coalbed methane production in Alabama: International Journal

o Coal Geology, v. 38, p. 89-113.

6. Groshong, R. H., Jr., Cox, M. H., Pashin, J. C., McIntyre, M.

R., 2003 Relationship between gas and water production and

structure in southeastern Deerlick Creek coalbed methane feld,

Black Warrior Basin, Alabama: Tuscaloosa, Alabama, University

o Alabama College o Continuing Studies, 2003 International

Coalbed Methane Symposium Proceedings, Paper 0306, 12 p.

7. Pashin, J. C., Gouhai Jin, and Payton, J. W., 2004, Three-

dimensional computer models o natural and induced ractures in

coalbed methane reservoirs o the Black Warrior Basin: Alabama

Geological Survey Bulletin 174, 62 p.

8. Pashin, J. C., Clark, P. E., Esposito, R. A., McIntyre, M. R.,

2007, Southeastern Regional Carbon Sequestration Partner-

ship (SECARB) Phase II, SECARB Black Warrior Basin Test

Site, Deerlick Creek Field, Tuscaloosa County, Alabama: Project

Design Package U.S. Department o Energy, National Technology

Laboratory, contract DE-FC26_05NT42590, 26 p.


13/16

Carbon Capture and Sequestration (CCS) technologies have signicantpotential to reduce atmospheric CO2 emissions by permanently storingCO2 in underground geologic ormations. As recently as 2004, however,

there were ew educational programs that ocused on implementing andmanaging CCS programs. Tis le people who were interested in climatechange solutions with ew opportunities to learn about CCS technologies.

Pamela omski recognized this decit and responded by starting theResearch Experience in Carbon Sequestration (RECS) program. RECSprovides training and education or early-career proessionals and studentsthrough a combination o classroom instruction and eld activities, whichtypically include visits to a geologic CO2 storage site, power plant, andnatural CO2 reservoir. Participants learn about CCS topics that encompassenergy studies, geology, climate science, and related elds.

omski organized the rst RECS program in 2004 with support rom theU.S. Department o Energy and other private organizations. Te RECSprogram has been popular since its inception and has seen a steadyincrease in interest. In 2010 RECS selected 30 participants out o severalhundred applicants. In the uture omski hopes to expand the programand hold two training sessions each year.

As part o the program, these up-and-coming proessionals are introducedto instruments used or CCS monitoring, including the LI-8100A Auto-mated Soil CO2 Flux System and the LI-7500A Open Path CO2/H2OAnalyzer. Both instruments are designed or outdoor deployment and areuseul or meeting Monitoring, Verication, and Assurance requirementswithin the CCS ramework. LI-COR instruments and technologies oersimple, powerul solutions or monitoring geological carbon storage sites,and are included in the RECS program to provide participants with hands-on experience using CCS monitoring technologies.

Ongoing research into CCS technology will resolve technical challengesand validate its value or limiting carbon emissions, while RECS will giveproessionals and students a head start by providing them with the diverseskill set required to implement eective CCS programs.

Research Experience in Carbon Sequestration (RECS) - 12

A RECS participantmakes soil CO2 ux

measurements with the

LI-8100 in New Mexico.

Research Experience in CarbonSequestration (RECS)


14/16

13 - Zero Emission Research and Technology (ZERT) Center

Te Zero Emission Research and echnology (ZER) Center isa research group ocused on understanding the basic science ounderground (geologic) CO2 storage and or developing tools

to ensure saety and reliability. ZER is a collaboration involv-ing several private corporations, DOE laboratories (Los AlamosNational Lab, Lawrence Berkeley National Lab, National En-ergy echnology Lab, Lawrence Livermore National Lab, andPacic Northwest National Lab), as well as Montana State andWest Virginia University.

In order to understand the possible ates o injected CO2,ZER is perorming laboratory experiments to understandCO2 physical and chemical interaction with geologic ormationminerals and uids. ZER is also developing monitoring and

verication techniques to determine the behavior o the under-ground CO2 and underground storage capacity or dierentgeologic ormations.

As part o the initial experiments, a 100 meter length o pero-rated pipe was installed at a depth o approximately 2.5 metersbelow the surace. Controlled release o CO2 into the pipe be-gan in the summer o 2007. Various groups at the site perormmeasurements to characterize leakage at the surace, as well asother biological measurements, including lea spectral measure-ments, ground water and below ground CO2 monitoring, and

Eddy Covariance ux measurements.

The chart above shows soil CO2 euxes measured by Jennier Le-

wicki o Lawrence Berkeley National Laboratory in 2009 and 2010.

LI-COR at ZERT

Te ZER Center graciously provided access to their reseachsite so that LI-COR scientists could get rsthand experience atan injection site, using the LI-8100A Automated Soil CO2 FluxSystem to measure CO2 efuxes with the enhanced 20,000ppm concentration range o the LI-8100A. In addition,LI-COR was able to test soil chamber collar adapters that in-

crease the volume:area ratio or 20 cm chambers (below).

And nally, LI-COR scientists tested a prototype intake tubeconnected to the LI-8100A Analyzer Control Unit, tted witha GPS unit, to test the easibility o using the LI-8100A todetect and map leaks at CO2 injection sites (below). Several

transects along the injection pipe were made, and were used togenerate a 3-D model o CO2 efux at the test site.

Te plot to the le shows CO2concentration on July 22, 2010,three days aer CO2 wasinjected through the pipe. CO2values ranged rom 360 ppm(base level) to a peak o 506 ppmin the center o the plot.

Zero Emission Researchand Technology (ZERT)Center


15/16

Acknowledgements and Ordering Inormation - 14

LI-8100A Analyzer Control Unit.Includes Auxiliary Sensor Interace, Serial Cable Interace, RS-

232 Serial Cable, RS-232 to USB Adapter, Spares Kit, Compact

Flash Memory Card, PC Card Adapter, Shoulder Strap Kit, Sot-

ware CD (Windows, Windows Mobile, and Palm Interace

plus Data Analysis Sotware) and Instruction Manual (Chamber,

Battery, and Battery Charger not Included)

Chambers

8100-102 Survey Chamber, 10 cm

Includes 8100-201 soil temperature probe, gasket kit, spares kit,

and six soil collars

8100-103 Survey Chamber, 20 cm

Includes 8100-201 soil temperature probe, gasket kit, spares kit,

and six soil collars

8100-104 Long-Term Chamber

Includes gasket kit, spares kit, and two soil collars

8100-104C Clear Long-Term Chamber

Includes gasket kit, spares kit, and two soil collars

LI-8100-M1 Four Chamber Multiplexed PackageIncludes LI-8100A Analyzer Control Unit, LI-8150-8 Multiplexer,

our 8100-104 Long-Term Chambers and our 8150-705 Cable/

Hose Assemblies. Requires AC or DC power (DC power cable

included). Auxiliary sensors sold separately.

LI-8100-M2 Four Chamber Multiplexed Package

Includes LI-8100A Analyzer Control Unit, LI-8150-16 Multiplexer,

our 8100-104 Long-Term Chambers and our 8150-705 Cable/

Hose Assemblies. Requires AC or DC power (DC power cable

included). Auxiliary sensors sold separately.

LI-8100-P8 Eight Chamber Multiplexed Package


eight 8100-104 Long-Term Chambers, eight 8150-705 Cable/

Hose Assemblies, 8150-706 DC power cable, eight 8150-203 soil

temperature thermistor,s and two year extended warranties or

the LI-8100A and LI-8150-8.

LI-8100-P16 Eight Chamber Multiplexed Package


sixteen 8100-104 Long-Term Chambers, sixteen 8150-705 Cable/

Hose Assemblies, 8150-706 DC power cable, sixteen 8150-203soil temperature thermistors, and two year extended warranties

or the LI-8100A and LI- 8150-16.

Greenhouse Gas Systems (GHG)*

GHG-1

LI-7700 Open Path CH4 Analyzer, 5m power and Ethernet cables,

calibration fxture, washer assembly, mounting hardware, radia-

tion shield, spares kit, carrying case, Windows sotware CD,

and instruction manual.

LI-7500A Open Path CO2/H2O Analyzer, LI-7550 Analyzer Contro

Unit, 5m IRGA cable, USB-to-serial adapter, 5m data cables (RS-232, Ethernet, DAC), calibration fxture, Windows sotware CD,


7550-101 Auxiliary Sensor Interace or analog inputs.

GHG-2

LI-7700 Open Path CH4 Analyzer, 5m power and Ethernet cables,

calibration fxture, washer assembly, mounting hardware, radia-

tion shield, spares kit, carrying case, Windows sotware CD,


LI-7200 Enclosed CO2/H2O Analyzer, LI-7550 Analyzer Control

Unit, 7200-101 Flow Module, 1m intake tube with insect screen,5m IRGA cable, USB-to-serial adapter, 5m data cables (RS-232,

Ethernet, DAC), calibration fxture, Windows sotware CD, and

instruction manual.

7550-101 Auxiliary Sensor Interace or analog inputs.

* The Greenhouse Gas Systems include the LI-7700 Open Path CH4

Analyzer, or those users interested in adding simultaneous eddy

ux measurements oin situmethane, as well as carbon dioxide

and water vapor.

Ordering Inormation

We would like to thank the Department o Energy (DOE) and the

National Energy Technology Laboratory (NETL) or their part in

organizing and unding the work involved in some o these proj-ects. We would also like to thank the Southeast Regional Carbon

Sequestration Partnership (SECARB) and the Midwest Geologica

Sequestration Consortium (MGSC) or their input and contribu-

tion to this document.

Acknowledgements


16/16

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line is covered by U.S. and oreign patents pending, and U.S. patents in-

cluding U.S. 7,509,836; 7,568,374; 7,748,253; and 7,856,899. The LI-7500A

analyzer is covered by U.S. Patent #6,317,212 and oreign equivalents.

The LI-7700 and LI-7200 analyzers are covered by U.S. Patents, patents

pending and oreign equivalents. Windows is a registered trademark

o Microsot. All brand and product names are trademarks or registered

trademarks o their respective owners. Copyright 2011, LI-COR, Inc.

Printed in the U.S.A.

The LI-COR board o directors would like to take this opportunity to return

thanks to God or His merciul providence in allowing LI-COR to develop

and commercialize products, through the collective eort o dedicated

employees, that enable the examination o the wonders o His works.

Trust in the LORD with all your heart and do not lean on your own

understanding. In all your ways acknowledge Him, and He wi ll make your

paths straight.

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surface monitoring for geologic carbon sequestration (2011, licor)

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