Borehole Based Monitoring of CO2 Storage:
Recent Developments in Fiber-Optic Sensing

Thomas M. (Tom) Daley
Barry Freifeld
Lawrence Berkeley National Laboratory

contributions from many project participants2014 RITE CCS Workshop, Tokyo
January 23, 2014
Photo: CO2 Venting at 2006 Frio Pilot Test

Outline• CO2 Monitoring – Brief Review– 1950-2000s:• Early Enhanced Oil Recovery (EOR) Tests• Development of reservoir monitoring• First CO2 Sequestration Specific Tests• Importance of monitoring wells• Look Forward: Large Scale Sequestration• Need for ‘adaptive’ monitoring well program• Fiber optic technology for monitoring wells– Background– Field testing and applications (CO2 monitoring)• Citronelle, Alabama, USA– Repeat with improvement• Otway, Australia– With surface cable testing• Ketzin, Germany– Multiple wells• Aquistore1950s – 1960s• Early EOR Tests: Laboratory and Field Studies– Torrey, 1951: Oil recovery by carbonic acid injection– Beeson and Ortloff, 1959, Laboratory investigation of the water-driven
CO2 Process for Oil Recovery– Budde, 1959, Geoph. Prosp.: Detection of CO2 in ground water(mineral water) via atmospheric measurements: (uses heatconductivity variation of CO2 vs N2/O2)

Holm, 1959, SPE.

1970s• Large Scale CO2-EOR Field Tests - SACROC Field– Crameik and Plassey, 1972, API: Carbon Dioxide
Injection Project SACROC Unit, Texas• Plan 37 Mton injection over 9 years in 202 injection
wells; 220 mile pipeline– Farr, 1978, SPE: “.. Seismic as a reservoir analysistechnique”• Until recently …pore fluid identification was considered… beyond the resolving power of the seismic reflection
method”– Richardson, 1979, JPT: Monitoring with Induction Logs:“ using the technique on a CO2 pilot flood”• Early Climate Change Concern in U.S.
– National Academy Report 19771977

1980-90s• Beginning of Subsurface Monitoring– Goodrich, 1980, SPE/DOE: Review of past and ongoing CO2 injection field tests• 19 projects - abstract has no mention of monitoring– Svor and Globe, 1982, SPE: “..Quantitative Monitoring for CO2 Floods”• Pulsed Neutron logging for co2 saturation– Widmyer, 1987, JPT: Use of Monitor Observation Wells For fluid sampling– Wang and Nur, 1989, SPE: Rock Physics - Effect of CO2 on Wave Velocities• Maturing Monitoring Tools– Wang, et al, 1998: McElroy CO2 Flood – Imaging w/Rock Physics– Huang, et al, 1998, TLE: Integrating reservoir model and seismic monitoring– Lumley 2001, Geophysics: 100 total and 75 active reservoir monitoring projects (4Dseismic)

1990s-2000s• Initial Sequestration Field Tests – All With Monitoring Program– Industrial• Sleipner(4D marine seismic)• Weyburn-Midale (also EOR)
• In Salah(success of InSAR)• Snohvit(2008 – marine seismic)– Research Pilots• Frio• Nagaoka• Otway• CO2Sink (Ketzin)(crosswell, continuous fluid sampling)(crosswell, multiple well logging)(multi-level continuous fluid sampling)(ERT, 4D seismic)• US DOE Partnerships (e.g. Cranfield, Decatur, etc.)– Wide range of monitoring tools tested

Early Success at Borehole Monitoring
McElroy Pilot Test 1995

Wang, et al,
1998;
Harris, et al,
1995

1996-?: Sleipner CO2 Injection:
Seismic Monitoring Success – No Mon.
Well (Courtesy of Statoil)

Time-lapse seismic data
1994

>13 Mtons Injected
2001
Utsira Fm.

CO2 plume in map view

2008

2008-1994

Chadwick, et al, 2010

Issues with Seismic Imaging:
Quantitative interpretation without other data may be difficult:
Data

ModelSleipner – 9 Layers?

How many layers at Sleipner?
No monitor well to aidinterpretation!
Reservoir Model (Sg) & Seismic Data

Injection Depth

D. Lumley, Leading
Edge, 2010

Synthetic
PSDM 4D seismic
difference

RealPSTM 4D seismic
difference

Arts and Vandeweijer,
Leading Edge, 2011

Large Scale Storage – Multiple Injectors
Need to Optimize Utilization and Location of Monitoring Wells~200 km

Large Scale Sequestration Model:
20 Injectors, 30 km apart, 5 Mton/year~8 km
each for 50 years

Monitoring Well

Modified from:
Birkholzer and Zhou, IJGGC, 2009.

Advances in Borehole Monitoring Methods areNeeded for CCS Projects
Motivation: Deep monitoring wells are expensive to drill andcomplete and have limited space available for instrumentation
Monitor CO2 plume location
Reservoir pressure andtemperature
Fluid samplingLeak detection
CO2 saturations

Goal: Develop a rugged, cost effective, multi-sensor monitoring
platform designed for a single-well• Distributed fiber optic sensor arrays• Modular Borehole Monitoring (MBM)

Advanced Borehole Monitoring Tool:
Fiber Optic - Distributed Sensor Arrays• Benefits:– Operate in harsh downhole environments– long potential life span, high data sampling rates,– high spatial resolution, adaptive to changing measurement technologies

Applications include:• Distributed temperature sensing (DTS)• Borehole strain measurements• Direct chemical detection• High density seismic arrays (DAS)

Subsea Fiber
optic cable
assembly– Leak detection– Compliance monitoring• Heat-pulse monitoring– Leak Detection– CO2 distribution behind casing– Flow monitoring and allocation

Citronelle
Deployment

Distributed Temperature Sensing (DTS)• DTS:– DTS used for past 20 years– Measurement of Ramanbackscattering, combined with
Optical Time-Domain
Reflectometry (OTDR),
determines temperature along
fiber length• Specifications vary withstacking time and length:• ~10 km fiber: spatial resolution
25 cm, temperature resolution
0.01°Cmeasurement time 1 s

3 km DTS Temperature

DTS Heat-Pulse Monitoring• Heat Pulse:– Copper heater elements (wire)
integrated with DTS fiber in the samecable provide distributed pulse ofheat– time-lapse measurement oftemperature during/after heating• Fluid substitution in well or porespace changes thermal properties
detected by heat pulse
measurment

Heat-Pulse Cable
HeaterElement

Fiber
Multiple heater elements
and fibers are integrated
into a 3/8” OD stainless steel
control line

Distributed Acousting Sensing (DAS)• DAS acquisition allows seismic monitoring withfiber optic cable• DAS has received great interest anddevelopment in recent years –– from Petroleum Technology (2012) to The
Economist (2014)– Early adoption for CCS monitoring (2011)

DAS• DAS acquisition• Sensitivity currently less than standard geophone, but…
– Spatial sampling and ease of deployment much greater• Easy deployment of DAS with other lines

Same cable as DTS
Heat-Pulse

DAS Theory• Light pulse is reflected throughout fiber’s length by Rayleigh scattering• DAS system measures changes of the backscattered light• An acoustic field around the fiber causes pressure/ strain on the fiber,
resulting in changes to the backscattered light• The DAS measures these changes by generating a repeated light pulse ate.g. 100 μs and continuously processing the returned optical signal• Up to 10 km in length, up to 10 kHz sample rate, and up to 1 m resolution
Single Pulse
Multiple Filtered Pulses
From Hartog, et al,EAGE, 2013

A 3 km single mode fiber becomes an acoustic array with up 3,000 sensors!

Deployment:
Modular Borehole Monitoring• Motivation: Maximize efficient useof available boreholes for semipermanent monitoring• Measurements of Interest– Pressure*– Temperature– Fluid Sampling*– Wireline logs
– Geophysical Monitoring• Seismic: active source and passive
monitoring• Electrical* Requires Packer for zonal isolation

The Previous Way:
6 Separate Lines

Modular Borehole Monitoring (MBM)
Conceived at Otway Pilot (Australia) 2007
• Concept: A package ofredeployable borehole
monitoring instruments• Example: Otway 2007
– Dedicated Monitoring well
– Fluid sampling was main monitoring
success (not seismic)
Geophone with clamp (VSP)

3c Geophone with clamp(Microseismic)
Hydrophone (seismic)
Pressure &Temperature

Fluid Sampling:
U-tube Inlet

Freifeld and Daley, LBNL & CO2CRC

Otway 2007:
Naylor-1 Monitoring well – 11 Lines
Problem: Deploying many
instruments and cables in small well
was challenging.

Modular Borehole Monitoring (MBM)• Tools Deployed with MBM– Discrete Pressure & Temperature (2 Quartz Gauges)– Distributed Temperature Sensing (DTS) with Heater (Heat-Pulse)– Fluid Sampling (U-tube)– Seismic monitoring• 18 clamping geophones– Distributed Acoustic Sensing (DAS)The MBM Improvement:
Flatpack and Geophone Cable

SECARB Anthropogenic Test
• Integrated Capture, Transmission,
Storage

Citronelle
Dome– CO2 Capture began June 2011
– Transportation via 19 km pipeline– Saline Storage at Citronelle Oil Field
began August 2012
Mobile,Alabama

SECARB Anthropogenic Test
Citronelle, Alabama• First integrated CO2 capture, transportation and storage project on a coalfired power station using advanced amines• Southern Co. and MHI have captured over 200,000 metric tonnes of CO2 todate• Denbury Resources has transported, injected and stored over 100,000 tonnes• Injecting CO2 into the Paluxy Formation, which has excellent storage capacityof regional significance23

Citronelle Storage

Courtesy of ARI

R&D Effort Focused on the MBM System inObservation Well

Injection
Well

D9-7#2

Observation
Well

D9-8#2CO2 injection well D9-7#2 and observation well D9-8#2• Observation well (D98#2):– ~250 m east of theCO2 injection well
– Perforated at a depthof ~2.8 km in PaluxyFormation

Deployment of MBMTubing Deployed (allows wireline access)4-element flatpack and sealed geophone cable
18-level Geophone array• Hydraulic clamps for Geophones• Clamp in tubing/casing annulus
Dual mandrel hydraulic packer• Non-rotating overshot connection for coupling to450’ bottom assembly• Avoids splices at packer

7” Casing2 7/8” TRS-8 TubingFlatpackGeophone TEC cable
Clamp Hydraulic line spliced
from flat pack18 Geophones

Breakout from flatpack

Geophone inclamp withflatpack

Packer~9400 ft

PackerNi Plated overshot
P/T Gauge
Perforated Chrome Tbg
U-tube fluid sample inlet
Fiber/Heater cable~9850 ft

P/T Gauge

MBM System Sensor Configuration• Fiber optic cable for distributed
temperature and acoustic
measurements- Heat-pulse monitoring for CO2
leak detection• Tubing deployed geophone array(6,000-6,850 ft)• Two in-zone quartz pressure/temperature gauges (~9400 - 9500 ft)• U-tube for high frequency, in-zone
fluid sampling (tube-in-tube design)• 2 7/8” production tubing open forlogging

Geophone pod and clamping assembly andyellow flat pack containing fiber cable

MBM Design: Flat-Pack and Geophone
Flatpack replaces 7 lines

DTS, Heater, DAS
Hybrid 6-copper, 4-fiber-optic cable

Welded Geophone LineCitronelle DAS VSP (Vertical Seismic Profile):• June 2012 and August 2013
• Citronelle Offers an Opportunity toCompare Seismic Methods to Monitor
CO2• Seismic monitorling at Citronelle:• ~60 shot points• 4–64 sweeps per location• Sweep: 16 s, 10–160 HzObservation
Well

2003

• Cross-well seismic surveys• Geophone VSP surveys using• 80-160 level 3C arrays in theinjector and D9-8#2• 18 geophone MBM array• DAS and MBM Geophone:• Source: vibroseis truck

2054

Injection
Well

2021
50 m

1

DAS-MBM Shot
Point
MBM Walkaway
Survey SP

2012 DAS Testing
3 km, Tubing Deployed•••

DAS VSP ‘piggy-back’ on standard acquisition
Initial data quality insufficient to observe P-wave
below ~1600 m, triggering needed improvement
Benefit: 3000 sensors versus 18SP 2021 located ~700 ft offset from the D-9-8 sensor
borehole. Estimated wave speeds for two events (redand blue lines) are labeled in km/s.

SP 2054 located ~100 ft offset from the D-9-8 sensor
borehole. Observed two tube waves.

Geophone Data

From Daley, et al, Leading Edge, 2013
Processed by D. Miller, Silixa

2013 DAS Testingvs MBM Geophone Comparison
Improvement: Acquisition of more source sweeps and improved triggering increased
DAS data signal to noise ratio, producing data comparable to more sensitive geophones
Approximately 9 dB difference in sensitivity – can be overcome with extra source effort.

Single Channel Comparison:
DAS 64 sweeps
comparable
to Geophone 24 sweeps

Courtesty D. Miller, Silixa

DAS Advantage in Number of Sensors•Comparison of data acquired from one source point–18 geophones vs 3000 DAS channels

DAS

7” Casing2 7/8” TRS-8 Tubing

Geophone PodFlatpack
Geophone TEC cable
Clamp Hydraulic line
spliced from flat pack18 Geophones

Geophone

Breakout of flatpack end:
9377’
Packer 9426’-9432’
Ni Plated overshot
P/T Gauge
Perforated Chrome Tbg
U-tube fluid sample inlet
Fiber/Heater cable
P/T Gauge

Courtesty D. Miller, Silixa

2013 Citronelle DAS vs MBM Geophone Comparison• Comparison of Spectral Response– DAS matches geophone

Courtesty D. Miller, Silixa

Fiber Optic Temperature at Citronelle
7” Casing2 7/8” TRS-8 Tubing• Heat Pulse withDistributed
Temperature Sensing(DTS)

Flatpack
Geophone TEC cable
Clamp Hydraulic line spliced
from flat pack18 Geophones

Breakout from flatpack

Packer~9400 ft

PackerNi Plated overshot
P/T Gauge
Perforated Chrome Tbg
U-tube fluid sample inlet
Fiber/Heater cable~9850 ftP/T Gauge

Monitoring with DTS Using Heat Pulse(Static Wellbore Conditions)•Heating
6 Watt/meter

Initial completion of wellincluded use of MBM fordiagnostic testing

Heated Temperature (Red)
Ambient Temperature (Blue)

PackerColder Kill Fluid— Heat Pulse locatedperforation w.r.t packer— Information used inregulatory assessmentof completion

End ofFlatpack

Below Perforations

Well Diagnostics Using Heat Pulse Monitoring
Flowing Annulus – Thermal Change (Green)

PackerPerforations
Lower Flow

Higher Flow

Depth (ft)

Citronelle Heat-Pulse Diagnostic Test• Location of the packer is determined ±1 ft.*
• Perforation flow zone interpreted from distinct coolingnoted from a 10±1.5 m zone.*• The thermal profiles indicate flow both above and below
the packer– strong likelihood that the packer has been set within theperforated interval* Depth measured from bottom of fiberCitronelle/MBM Summary• SECARB’s Anthropogenic Pilot is an operational integrated
CCS project• A modular borehole monitoring (MBM) system wasdesigned, built and deployed for Citronelle• The MBM system includes:– P/T gauges, U-tube fluid sampling, hydraulic clampinggeophones,– Fiber optic temperature (with heat pulse) and seismic (DAS)• MBM system is operational and was useful inunderstanding well completion• Following initial proof-of-concept testing MBM DAS VSP
acquisition was improved and is very promising– Sensitivity within ~9 dB of clamped geophones

DAS Testing at Otway: 2012
Stage 2: Well CRC-2• ~1400 m, Tubing Deployed Fiber plus Surfacecable• DTS (with heat pulse)• DAS

http://www.co2crc.com.au/Otway DAS included borehole (VSP) and surface cable

Weight Drop Source40 cm deep trenchwith FO cable loop

CRC-2

From Daley, et al, Leading Edge, 2013

Otway DAS VSP
Raw Stacked Data

Reflections (upgoing)

Data Compared to previous
wireline geophone VSP
Increase Source Effort (stack 41 vs 5-10)
From Daley, et al, Leading Edge, 2013

Otway Tubing DAS VSP vs Clamped Wireline
Geophone Signal/NoiseDASGeophones

How Much Extra Source
Effort?

2012 Otway test says 40 dB2013 testing at Citronelle
indicates ~9 dB

From Daley, et al, Leading Edge, 2013

Otway is not simultaneous
acquisition -> Citronelle
better comparison
Note: Stack of 100 = 20 dB

Otway DAS Surface Data
Single Cable: Borehole and SurfaceSurface
TrenchSurface
TrenchFrom Daley, et al, Leading Edge, 2013

Parallel Surface Cables (Loop)
Very Similar Response
Two individual channels (1 msegments

From Daley, et al, Leading Edge, 2013

Cross correlation of all channels:
Time shifts < +/- 1 ms
Correlation Coefficent:~0.8-0.95

DAS as Surface Seismic Cable:
Stacking Different Fiber Lengths
Directionality of DAS limits reflection signal: can improve by stacking, but
Surface waves dominate signal compared to vertical geophones

From Daley, et al, Leading Edge, 2013

Otway DAS: Surface Wave Analysis
Result: Useful data for near surface properties(spectral analysis of surface waves – SASW)

From Daley, et al, Leading Edge, 2013

Otway Test Summary• DAS VSP data ~40dB below high quality geophones– Note: great improvement seen at second Citronelle test

• Simultaneous borehole and surface data on onecable• DAS Surface wave data analysis is good quality

Ketzin Project• CO2 Storage Pilot operated by the German Research Centre for Geosciences (GFZ);
Injection at ~700 m• Injection well and 3 observation wells• DAS acquisition in 2012 (2 wells) and 2013 (4 wells)• Weight Drop Source (240 kg)

Distributed acoustic VSP source:Geophysik GGD, Leipzig, Germany

Ketzin: 2012 DAS survey – 2 Wells• Two Wells Simultaneous• Fiber Behind Casing• Surface connecting fiber added for VSP

Good Quality Data: Various Waves Observed(A) Extensional signal
propagating inundamped casing
above 269m (5.5km/sec)(B) Directcompressional
formation arrival (3km/sec)(C) Tubewave
propagating in fluidannulus above 460m
(1.35 km/sec)(D) Reflected
formation arrivalfrom reflector at540m(E) Downgoing
formation shear(1.67 km/sec)

Courtesty D. Miller, Silixa

Fiber deployed behind casing, but not cemented at all depths
DAS records waves related to well casing completion

Weak signal at ~650m in both geophone and DAS data – no cement

From Daley, et al, Leading Edge, 2013
Courtesy J. Gotz, GFZ

Aquistore DAS 3D-VSP
2 Example Shots•••~3 km Fiber Behind Casing, cemented, explosive shot
Initial recording May 2013 of >200 shots
Second recording Nov 2013 > 600 shots; being processed analyzed

05001000

May 2013 DAS VSP• Currently: Processing of individual shots

Shot Points: 6971113 114

750 mObservation Well136

May 2013 Aquistore: Shot #136 (730m offset)
VSP Reflection Image

Possible
Reservoir
Reflection
At ~3.2 km

New Data: Aquistore Nov 2013
DAS and Geophone 3D-VSP

Compare:DAS and Geophones;
Vibroseis and explosive;
Single mode and Multi-mode
Results Soon!!

Summary 1•••••CO2 monitoring needs improved borehole methods
DAS and Heat-Pulse DTS are new, useful fiber-optic applications
Modular borehole deployments make sense for CCS monitoring
DAS testing conducted within CO2 monitoring R&D
Citronelle site
– Tubing deployed, 2.9 km, with short 260 m geophone string– Initial test had relatively low sensitivity– Repeat test greatly improved, about 9 dB below geophones, goodpotential for monitoring• Otway site,– Tubing-deployed, 1.5 km, poor in comparison with previous
geophone survey– Larger source effort needed, but promising result– Surface cable gives useful dataSummary 2• Ketzin site,– casing deployed, ~750 m– Multiple wells recorded simultaneously on single cable loop
– good overall data quality but adverse effects from uncemented zones.
– DAS data has upgoing VSP reflections over the ~700-m depth of thewell.
• Aquistore Site
– Casing deployed, 3 km
– Good quality data
– Repeat with wireline 3-C geophones• DAS is very promising technology, which is still improving• Fiber optic sensing, in general, has application for CCS:
– Improved monitoring while reducing risk from monitoring wells

Acknowledgements•

The authors thank:– the U.S. Department of Energy,– the SECARB partnership,– the CO2 Capture Program (CCP)– the Electric Power Research Institute, Advance Resources International, and Denbury Resources Inc.
for support of the Citronelle work;– the CO2CRC Otway Project for Otway test support;– the GFZ and CO2MAN project for Ketzin support.
– PTRC, GSC for Aquistore project support

MBM work funded by CCP, www.co2captureproject.org ; Deployment supported by SECARBDAS Testing Contributors include: :– Jonathan Ajo-Franklin, Shan Dou, Victor Leung, John Peterson, Michelle Robertson, Paul Cook (all atLBNL)– Sudhendu Kashikar And Douglas E. Miller, Silixa– Roman Pevzner, Co2crc, Curtin Universty
Valeriya Shulakova, Co2crc, Csiro
Julia Goetz, Jan Henninges, And Stefan Lueth, (All At Gfz)•

This research was partially supported by the assistant secretary for Fossil Energy, office of natural gas andpetroleum technology, CSRP/GEO-SEQ Program, through the National Energy Technology Laboratory of theU.S. Department of Energy, under U.S. DOE Contract No. DE-AC02- 05CH1123.

Questions?

Photo: Citronelle
Southeast Regional Carbon Sequestration
Partnership (SECARB):
Anthropogenic CO2 Injection Field Test
Monitoring Well:
Citronelle D-9-8 #2