Post on 16-Jan-2017
Advancements in Tracer Flow Testing; Development of Real-Time Technology for
Flow and Enthalpy Measurements
USC Center for Geothermal StudiesDistinguished Speaker Program
USC Center for Geothermal Studies 27 February 2012 © Thermochem, Inc
Flow and Enthalpy Measurements
Tracer Flow Testing-Core Principles
What is Tracer Flow Testing (TFT)?Tracer Flow Testing is the measurement of single- or multi-phase fluid flow by the injection and dilution of phase-specific chemical tracers.specific chemical tracers.
Its primary application in the geothermal industry is monitoring enthalpy and mass flowrate of vapor and liquid at each stage in the power generation process, from production well, to power plant, to reinjection.
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Core Principles
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Core Principles
Mass rate of liquid (Q L) and vapor (Q V) is given by:
QL,V = QT / CT
Q = Mass Rate of Fluid (Liquid or Vapor)QL,V = Mass Rate of Fluid (Liquid or Vapor)
QT = Tracer Injection Mass Rate
CT = Tracer Concentration by Weight
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Core Principles
Tracer Flow Testing (TFT) is a “steady state” method in which tracer is metered into the process flow path on a continuous basis and simultaneously sampled downstream of the injection point.
TFT is not a “time of flight” method in which the bul k velocity of the fluid is determined by injecting a pulse of tracer and then monitoring its arrival time at various sample points along the pro cess flow path.
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Core Principles
What is Continuous Tracer Flow Testing (CTFT)?
Continuous tracer flow testing (CTFT) is the measurement of mass flow rate and enthalpy in real time. The real -time process is time. The real -time process is made possible by the use of in-field tracer analysis technology.
CTFT utilizes standard TFT tracers, injection equipment and sampling equipment and therefore maintains the advantages inherent to that system.
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- CTFT Tracers
Tracer Selection Criteria for CTFT
� Each tracer must partition completely into its resp ective phase:The liquid-phase tracer must be highly soluble in w aterThe gas-phase tracer must have high volatility to f acilitate vaporization
� The tracers must be thermally and chemically stable under process conditions
� Quantitative, precise analytical methods with wide linear ranges must be available
� Natural background concentrations of the tracers mu st be relatively low and stable or nonexistent.
� The cost of the tracers must be reasonable for the quantities to be injected
� Non-radioactive and non-toxic
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- CTFT Tracers
� Fluoride (as KF)
� Bromide (as NaBr)
� Fluorescein dye
The liquid-phase tracers that have been evaluated f or CTFT are:
high detection limit, reactive
high detection limit, no field analysis
pH dependence, temperature limitations� Fluorescein dye
� Sodium benzoate
� Rhodamine WT dye
� 1,5-naphthalene disulfonate
� 2,7-naphthalene disulfonate
� Proprietary ThermoTrace
pH dependence, temperature limitations
high detection limit, interferences
pH dependence, temperature limitations
low frequency wavelength emission, interferences
low frequency wavelength emission, interferences
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- CTFT Tracers
� Propane
� Freon-12
� Helium
The Vapor-phase tracers that have been evaluated ar e:
high detection limit
no longer available
high detection limit, no field analysis� Helium
� Isopropanol
� Perfluorcarbons
� Sulfur hexafluoride (SF 6)
high detection limit, no field analysis
high detection limit, partitioning
cost, required for HP-TFT
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- CTFT Tracers
The optimal CTFT Tracers are:
ThermoTrace Sulfur Hexafl uoride
� > 50% solubility in water
� Detection limit of < 1 ppb
� Heat stability > 250°C
� Mixture pressures of 2900 psi
� Detection limit of < 0.005 ppb
� Thermally stable and inert below 500°C
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Field Ops
• The TFT measurement process does not disrupt plant or injection systems nor does it cause production loss.
USC Center for Geothermal Studies 27 February 2012
production loss.
• No modifications or expensive installations needed on pipelines. Only small ports required for injection and sampling.
Tracer Flow Testing- Field Ops
Applicable over a wide range of conditions –� Steam fraction: 1 to 99 %� Pressure: 0 to 5000 psig� Flowrate: 0.5 to 5000+ KPH
True average flowrates integrated over a desired ti me interval –True average flowrates integrated over a desired ti me interval –� Not affected by flow and pressure surges
Enthalpy and Mass Flowrates (Steam Fraction) based on Fundamental Principles and Traceable to Primary St andards -� Not an empirical correlation
No Radioactive or Toxic Chemical Tracers Used
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Injection System Original Tracer Metering Systems were truck-mounted skids……
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Injection System
The gas tracer is metered by the MicroMFC , a high-precision mass flow controller that accurately meters the gas tracer (+/- 1.5%).
MicroMod Tracer Metering System
meters the gas tracer (+/- 1.5%).
The liquid tracer is metered by the MicroLDS , a high-precision liquid delivery system that accurately meters the liquid tracer (+/- 0.5%).
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Tracer Sampling
Two-Phase Sampling in Wellfield
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Tracer Sampling
Sample Bottles and Cooler
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Tracer Analysis
Liquid Tracer Analysis On-site Lab
Vapor Tracer Analysis On-site Lab
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Real Time Analysis
MicroMod Continuous Brine Monitor (CBM)
• Real-time analysis of liquid phase tracer by custom LED flow-through fluorescence detector.
• Automated data logging, temperature correction and output for real-time applications.
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Real Time Data
Field SF 6 Analyzer(Prototype)
• Automated pre-treatment of vapor to remove H2O, CO2, H2S. Not to remove H2O, CO2, H2S. Not affected by total NCG levels.
• Automatic sample injection and analysis by Electron Capture Detection (ECD) method.
• Automated data processing and output for real-time applications.
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Real Time Data
Field SF 6 Analyzer(in development)
• Flow-through sample chamber • Flow-through sample chamber and analysis by infrared absorption
• True real-time SF6 measurement
• Automated data processing and output for real-time applications.
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Real Time Data
Well 1067Thermotrace Injection Rate and Measured ppb TT in B rine
200
300
ppb
TT
in B
rine
60
TT
Inje
ctio
n R
ate
(gra
ms/
min
)
ppb TT in Brinegrams/min TT Injection Rate
Injection
0
100
200
9:43 10:04 10:26 10:48 11:09 11:31Time
ppb
TT
in B
rine
0
20
40
TT
Inje
ctio
n R
ate
(gra
ms/
min
)
Injection start(~16 gr/min)
Increase injection rate(~30 gr/min)
Injection stop
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Real Time DataWell 5 Brine Flow
Discrete Sample Data
250
300
350
400Discrete Sample Data
Discrete Sample Data:Avg. Brine Flow Rate = 40.9 KPH
0
50
100
150
200
11:48 12:17 12:46 13:14 13:43Time
KP
H
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Real Time DataWell 5 Brine Flow
CTFT Data vs. Discrete Sample Data
250
300
350
400Discrete Sample DataCBM Data
Discrete Sample Data:Avg. Brine Flow Rate = 40.9 KPH
CBM Data:Avg. Brine Flow Rate = 31.0 KPH
0
50
100
150
200
11:48 12:17 12:46 13:14 13:43Time
KP
H
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Data Flowchart
Mass flow of each phase
(QL,V = QT / CT)
Mass Flow Controller
SF6 mass injection rate (Q )
Continuous Steam Monitor
SF6 concentration in steam (C )
Total Fluid Enthalpy)H(Q)H(Q
H LLVV ×+×=
Tracer Injection Tracer Analysis
injection rate (QT)
Liquid Delivery System
TT mass injection rate (QT)
in steam (CT)
Continuous Brine Monitor
TT concentration in brine (CT)
Steam Separator
Steam Enthalpy
(HV)
Brine Separator
Brine Enthalpy
(HL)
)Q(Q)H(Q)H(Q
HLV
LLVVT +
×+×=
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Real Time Data2-Phase Flow Rates and Fluid Enthalpy for Well-2 (C TFT vs. TFT)
600
800
1000
KP
H M
ass
Flo
w
400
500
600
700
Total Fluid Enthalpy
Tot
al fl
uid
Ent
halp
y (B
TU
/lb)
0
200
400
600
11:15 12:27 13:39 14:51 16:03 17:15Time
KP
H M
ass
Flo
w
0
100
200
300
400
Brine Flow Rate
Steam Flow Rate
Tot
al fl
uid
Ent
halp
y (B
TU
/lb)
USC Center for Geothermal Studies 27 February 2012
Tracer Flow Testing- Future Development
�Reducing detection limits for brine and steam
tracers
�Reducing cost of tracers to < $100/year�Reducing cost of tracers to < $100/year
�Downhole TFT for vertical profiling of steam
and brine mass flow
USC Center for Geothermal Studies 27 February 2012
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