1

Intrinsic Fiber Optic Chemical Sensors for Subsurface Detection of CO2

Intelligent Optical Systems, Inc.

Jesús Delgado Alonso, PhDRobert A. Lieberman, PhD

DOE Technical Monitor: Barbara Carney

2

Intelligent Optical Systems, Inc. (IOS)

Founded in April, 1998 Focus areas:

Physical, chemical, and biomedical optical and electronic sensors

Advanced light sources and detectors >$3.5M in equipment 11,500 sq. ft. facility in Torrance, CA Several spin-off companies with >$22M in

private funding

3

Technology

History and Objectives

Project Phases

Progress

Planned Work

Conclusions

Intrinsic Fiber Optic Chemical Sensors for Subsurface Detection of CO2

4

Problem/Opportunity

Reliable and cost-effective monitoring is important to making gas sequestration safe

Desirable analytical systems characteristics: Provide Reliable Information Monitor continuously Cover large areas Operate for years with little or no maintenance Cost effective Differentiate between CO2 variations due to natural processes and those

due to leaks of exogenous gas

5

Technology

Distributed intrinsic fiber optic sensors for the directdetection of carbon dioxide.

Unique characteristics: Direct measurement of CO2

The entire length of an optical fiber is a sensor

Sensors are capable of monitoring CO2 in water and in gas phase

A single cable may include CO2, pH, salinity, and temperature sensors.

6

A silica glass core fiber is coated with a polymer cladding containing a colorimetric indicator

Upon exposure of any segment of the fiber, the CO2 diffuses into the cladding and changes color

A change in fiber attenuation at wavelengths relating to the color change is detected.

(Left) Fiber structure of colorimetric distributed fiber optic sensors; (right) fiber optic CO2 sensor rolled onto a spool. Microscopic detail shows uncoated fiber, and fiber coated with the sensitive cladding.

Technology

7

The extent of color change (or attenuation change) depends on theconcentration of CO2, and is reversible

Wavelengths far from the absorbance of the indicator dye are unaffected by thepresence of CO2, which enables the system to be self-referenced.

Time (s)

4000 6000 8000 10000 12000 14000

Sen

sor S

igna

l (co

unts

)

6000

8000

10000

12000

14000

0.0% CO2

1.0% CO2

6.0% CO2

Reference wavelength6.0%

1.0%

0.0%

6.0%

1.0%

0.0%

Technology

8

Wavelengths far from the absorbance of the indicator dye are minimally, or completely, unaffected by the presence of CO2, enabling the system to be self-referenced.

Time (min)

0 5 10 15 20 25 30

Tran

smis

sion

(cou

nts)

365

370

375

380

385

390

Reference SignalRaw Sensor Signal

Time (min)

0 5 10 15 20 25 30

trans

mis

sion

(cou

nts)

365

370

375

380

385

390

Compensated Sensor SignalRaw Sensor Signal

0.5% CO2

0.0%

1.0%

2.0%4.0%

0.0%

0.5%

Technology

9

In sensor system deployment, the sensor fibers must be mechanically protected within a cable, while simultaneously allowing the free exchange of gases and water between the environment and the sensor fibers.

Technology: Sensor Protection for Field Deployment

10

Downhole CO2 monitoring

Distributed fiber optic

sensor for O2

Distributed fiber optic

sensor for H2O

Multi sensor unit

incorporating CO2, O2,

humidity, and

temperature sensors

Distributed fiber optic

sensor for O2

Distributed fiber optic

sensor for H2O

Multi sensor unit

incorporating CO2, O2,

humidity, and

temperature sensors

Distributed fiber optic

sensor for pH

Distributed fiber optic

sensor for salinity

Multi sensor unit

incorporating CO2, pH,

salinity, and temperature

sensors

Sensor network

Distributed fiber optic

sensor for pH

Distributed fiber optic

sensor for salinity

Multi sensor unit

incorporating CO2, pH,

salinity, and temperature

sensors

Sensor network

Dissolved CO2 in aquifers Near-surface leaks into the atmosphere

Advanced sensors for

CO2 (at high T and P)

Readout unit for long

sensors (>2 km)

Deployment system and

sensor cables for

downhole monitoring

Advanced sensors for

CO2 (at high T and P)

Readout unit for long

sensors (>2 km)

Deployment system and

sensor cables for

downhole monitoring

SBIR Project (2010 – 2013)Distributed Sensors for Dissolved CO2

Core Technology

Project History

11

Downhole CO2 monitoring

Distributed fiber optic

sensor for O2

Distributed fiber optic

sensor for H2O

Multi sensor unit

incorporating CO2, O2,

humidity, and

temperature sensors

Distributed fiber optic

sensor for O2

Distributed fiber optic

sensor for H2O

Multi sensor unit

incorporating CO2, O2,

humidity, and

temperature sensors

Distributed fiber optic

sensor for pH

Distributed fiber optic

sensor for salinity

Multi sensor unit

incorporating CO2, pH,

salinity, and temperature

sensors

Sensor network

Distributed fiber optic

sensor for pH

Distributed fiber optic

sensor for salinity

Multi sensor unit

incorporating CO2, pH,

salinity, and temperature

sensors

Sensor network

Dissolved CO2 in aquifers Near-surface leaks into the atmosphere

Advanced sensors for

CO2 (at high T and P)

Readout unit for long

sensors (>2 km)

Deployment system and

sensor cables for

downhole monitoring

SBIR Project (2010 – 2013)Distributed Sensors for Dissolved CO2

Core Technology

Project Objectives

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Phase I Development of advanced intrinsic fiber optic sensors and readout

(length up to 2,500 ft. and able to withstand corrosive liquids).

Sensor evaluation and demonstration in simulated subsurface conditions.

Phase II

Subsurface sensor deployment and operation (in a 5,900 ft. deep well at up to 2,000 psi).

Phase III

Project Phases

13

Develop an optoelectronic unit for remote operation.Preliminary design – select zone-by-zone or OTDR approach based on cable range and cable coverage.

Zone-by-zone: Better sensitivity Longer range

OTDR:Better spatial resolution

Progress: Optoelectronic Unit

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The zone-by-zone approach was selected based on calculations that showed the feasibility of this design in meeting the cable rangerequirement (up to 2,500 ft.).

Distribution Fiber Length

(m) (each segment)

Distribution Fiber

Attenuation (dB)

Sensing Segment

Length (m)

Sensing Segment

Attenuation (dB)

Total Attenuation

(dB)

Cable range (m)

Cable Coverage for 4 segments

(m)

1,000 20 25 2 21 1,000 2001,000 19 50 4 23 1,000 4001,000 18 100 7 25 1,000 8002,000 40 25 2 41 2,000 2002,000 39 50 4 43 2,000 4002,000 38 100 7 45 2,000 8003,000 60 25 2 61 3,000 2003,000 59 50 4 63 3,000 4003,000 58 100 7 65 3,000 8003,000 55 250 18 73 3,000 1,000

1,20

0 m

800

m

Progress: Optoelectronic Unit

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LED/Laser Drivers & Switch

Amplifier

Gain Control

Microprocessor

Signal Generator

Flash Memory Optional

ADC

DAC

PMT

Communications

User InterfacePower Module

RX Module Control Module

TX Driver Module

Combiners

TX Optical Module

Fiber Optic Sensors

Optical Module

Tx-Rx Module Control Module

Progress: Optoelectronic Unit

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Time (seconds)

0 500 1000 1500 200

Vol

tage

(V)

0.605

0.610

0.615

0.620

0.625

0.630

0.635

0.640

0.0% CO2

5.0% CO2

15.0% CO2

Fiber optic sensor cable with length of 2,100 m (6,890 ft.)Average (5% CO2) = 0.6223 VStandard Deviation (n=25) = 0.0005 VNoise to Signal = 0.08%

Progress: Optoelectronic Unit, Cable Range

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Films coated on glass slides Fiber optic sensor prototypes

1. Fabrication of films2. Evaluation of optical and

chemical properties3. Selection of candidate

formulations4. Fabrication of fiber sensor5. Preliminary testing6. Further characterization/

fabrication of films

Progress: Advanced Sensor Materials

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Transmission

Sensitivity and reversibility

Thermal stability

Time (s)

14000 16000 18000 20000 22000 24000

Ref

eren

ce S

igna

l (co

unts

)

5000

10000

15000

20000

25000

30000

35000

40000

45000

Sens

or S

igna

l (co

unts

)

4000

6000

8000

10000

12000

Time (minutes)

0 50 100 150 200

Ref

eren

ce S

igna

l (co

unts

)

700

750

800

850

900

950

1000

Sen

sor S

igna

l (co

unts

)

520540560580600620640660680700720740

Wavelength (nm)300 400 500 600 700 800

Tran

smitt

ance

(%)

50

60

70

80

90

100

IOS -21-2DC 3-1944

Resistant to water immersion

Chemical stability

Attachment to glass

Progress: Advanced Sensor Materials

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In the production of sensor prototypes, we use pre-fabricated silica glass "thread" as the core material, and apply the polymer cladding to the fiber with an optical fiber spooling machine, custom-built for fiber coating applications.

Glass core

Polymer cladding

Uncoated fiber

Coated fiber

Progress: Fiber Optic Sensor Production

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Fiber sensor at ambient

conditions

CO2 CO2

Progress: Sensor Testing

V1 V2

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Gas/water input

Gas/water output

Fiber optic sensor segment

Progress: Sensor Testing

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Time (hours)

21.0 21.5 22.0 22.5 23.0 23.5 24.0

Ref

eren

ce S

igna

l (co

unts

)

0

5000

10000

15000

20000

25000

30000

Sen

sor S

igna

l (co

unts

)

21500

22000

22500

23000

23500

24000

24500

25000

25500

3% CO2

6% CO2

0% CO2

Temperature 80⁰C

Time (hours)

134.5 135.0 135.5 136.0 136.5 137.0

Ref

eren

ce S

igna

l (co

unts

)

0

5000

10000

15000

20000

25000

Sen

sor S

igna

l (co

unts

)

17600

17800

18000

18200

18400

3% CO2

6% CO2

0% CO2

Temperature 100⁰C

As expected, sensitivity is reduced with increased temperature.

Progress: Sensor Testing at Elevated Temperature, Gas Phase

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Test Progress

Initial 120C Cycle 1 120C Cycle 2 120C Cycle 3 120C Cycle 5 120C Cycle 6 120C Cycle 7 150C Cycle 8

Nor

mal

ized

Sen

sor S

igna

l

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0.0% CO2

1.0% CO2

6.0% CO2

Test Progress

Initial 120C Cycle 1 120C Cycle 2 120C Cycle 3 120C Cycle 4 120C Cycle 5 120C Cycle 6 120C Cycle 7 150C Cycle 8

Nor

mal

ized

Sen

sor S

igna

l

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0.0% CO2

1.0% CO2

6.0% CO2

Fiber sensors withstand 120°C Significant degradation at 150°C

150°C120°C

150°C120°C

The fiber sensors are exposed to cycles of elevated temperature and ambient temperature.

Progress: Sensor Testing at Elevated Temperature, Gas PhaseAccelerated Degradation Test

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Test Progress

Initial 70C C1 70C C2 70C C3 70C C4 70C C5 70C C6 70C C7 70C C8

Nor

mal

ized

Sen

sor S

igna

l (Se

nsiti

vity

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0.0% CO2

1.0% CO2

6.0% CO2

Improved sensor formulations are stable at 70°C, the maximum temperature tested.

Tests at higher temperatures must be conducted at pressure.

Progress: Sensor Testing at Elevated Temperature, Dissolved CO2

Accelerated Degradation Test

Test Progress

Initial 70C C1 70C C2 70C C3 70C C4 70C C5 70C C6 70C C7 70C 10 70C C13 70C C16

Nor

mal

ized

Sen

sor S

igna

l (S

ensi

tivity

)

0.0

0.5

1.0

1.5

2.0

0.0% CO2

6.0% CO2

10.0% CO2

25

Time (minutes)

0 100 200 300 400 500 600

Ref

eren

ce S

igna

l (co

unts

)

1000

1020

1040

1060

1080

1100

Sen

sor S

igna

l (co

unts

)

150

200

250

300

350

400

450

0.0%

1.0%

2.0%

5.0%

Response profiles of a CO2 fiber optic prototypesimmersed in a pH 4.0 solution equilibrated withfour levels of CO2

Corrosive liquids: Acid matrix (pH = 4.0)

Standard conditions: Sensitivity, reversibility, measurement range

Time (minutes)

0 100 200 300 400 500

Ref

eren

ce S

igna

l (co

unts

)

200

220

240

260

280

300

320

340

360

Sen

sor S

igna

l (co

unts

)

0

1000

2000

3000

4000

5000

0.0%

1.0%

2.0%

5.0%

10.0%

0.5%

Progress: Sensor Testing at Extreme Conditions, Dissolved CO2

26

Corrosive liquids: Traces of NOx or SOx (40 ppm NO2)

Time (minutes)

0 20 40 60 80 100 120 140 160S

enso

r Sig

nal (

coun

ts)

48000

50000

52000

54000

56000

58000

60000

62000

Response profile after NO2 releaseResponse profile before NO2 release

0.0%

5.0%

10.0%

Response profiles of CO2 fiber optic prototypesimmersed in solution before and afterequilibration with traces of NO2 (40 ppm) andequilibrated with three levels of CO2.

Corrosive liquids: High salinity (250,000 ppm NaCl)

Time (minutes)

0 100 200 300 400 500 600

Ref

eren

ce S

igna

l (co

unts

)

1000

1050

1100

1150

1200

1250

1300

1350

Sen

sor S

igna

l (co

unts

)

100

200

300

400

500

600

700

0.0%

3.0%

13.0%

37.0%

Response profiles of CO2 fiber optic prototypesimmersed in a 250,000 ppm NaCl solutionequilibrated with four levels of CO2.

Progress: Sensor Testing at Extreme Conditions, Dissolved CO2

27

Ongoing and Planned Work

Perform Accelerated Degradation Testing High flow rates of corrosive water, exposure to highly biologically-

contaminated media, exposure to temperature cycles, exposure to high power illumination…

Evaluate sensors at elevated pressure

Perform analytical characterization of sensor system

28

Design and test sensor cables Design and assemble sensor

deployment system Sensor deployment and validation in the

field.

Proposed CO2 Sensor Well Number DOE-1

Well Test Configuration

20" 65#, H Conductor Pipe 150'@150' in 26" hole

13 3/8" 54#, K-55 Surface Casing @1500' in 17 1/2" hole 1500'Cemented to Surface

9 5/8" 53.5#, N80 Casing@5350' in 12 1/4" holeCemented to Surface

Fiber Optic CO2 Sensor Cable

1/4in Stainless TubingAdjustable Depth for CO2 Injection

Plugged Back Depth 5250'

Ongoing and Planned Work

29

A fiber optic sensor for CO2 monitoring in gas phase, capable of operating at elevated temperatures, has been demonstrated.

A fiber optic sensor for dissolved CO2 monitoring in aqueous matrixes, capable of operating in corrosive environments and at elevated temperatures, has been demonstrated.

Instrumentation demonstrating satisfactory performance while operating sensor cables 2 km long has been developed. Calculations predict continued good performance for sensors 3 km and even longer.

Test at elevated pressure will be performed in the following months.

The project is on schedule, and there is no technical impediment to conducting downhole monitoring

Conclusions

30

The Oil Industry is watching THE PROJECT...

Shell : There is a high level of interest in you company CO2-related projects

Conclusions

31

Intelligent Optical Systems, Inc.: Sensor developmentJesús Delgado Alonso and Robert A. Lieberman

Bureau of Economic Geology at UTA: Sensor field validation and modelingChangbing Yang

GeoMechanics Technologies: Downhole sensor deploymentMichael S. Bruno

Benson Laboratory at Stanford University: Sensor laboratory testingProf. Sally Benson and Ferdinand F. Hingerl

Montana State University (ZERT): Sensor field validationKevin Repasky

NETL Department of EnergyBarbara Carney, Robie Lewis, Robert Noll, Joshua Hull

Participants