Viscometer State-of-the-Art
Robert Kasameyer
Dan Airey
Jon Cole
January 22, 2010
© 2010 Cambridge Viscosity, Inc
Agenda
•
Comparison of commercially available high-pressure viscometers
•
Operating characteristics of a premier instrument: VISCOlab PVT
•
Development directions at Cambridge Viscosity
•
Need to extend viscosity standards for pressure and temperature
But first, a brief introduction to Cambridge Viscosity….
© 2010 Cambridge Viscosity, Inc
Cambridge Viscosity History
Founded in 1984 as Cambridge Applied
Systems
Cambridge Viscosity since 2006 to
emphasize our core business
Developed first high-pressure viscometer for
reservoir fluids in 1990
Technology leader in viscosity
Thousands of installations worldwide
Process and lab viscometers
Compliance with ASTM D7483-08
© 2010 Cambridge Viscosity, Inc
Comparison of Commercial Alternatives
Oscillating piston/
electromagnetic viscometer
© 2010 Cambridge Viscosity, Inc
Capillary
Rolling ball
Vibrational
Capabilities of Commercial Alternatives
Oscillating Piston
Capillary Tubes
Rolling Ball
Vibrational
Accuracy
±1% †
± 1%‡
±1–2%‡
na§
Sample per test
5 mL
25–100 mL
500 mL +
50 mL+
Max. pressure rating
20,000 psi ††
15,000 psi
10,000 psi
Atmospheric
Mercury free
Yes
No
Yes
Yes
Clean in place
Yes
No
No
No
Measures gas viscosity
Yes
No
No
No
Temperature range
–20 to 190 degC ††
Elevated only‡‡
Elevated only‡‡
–40 to 150 degC
†Published
literature: ± 1–3%
user survey: ± 5–15%
§Not applicable
† †Elevated options are now available
‡ ‡Baths may be available
‡Informal
© 2010 Cambridge Viscosity, Inc
Source: Available Published Information
Oscillating Piston Viscometer Technology
•
Piston motion is a function of acceleration, velocity, and
displacement forces.
Line fluid
Of these, velocity dominates.
Sensor
Piston
•
Velocity is determined by the piston’s drag due to shape and the
fluid dynamic viscosity.
The force due to piston wall overwhelms other drags.
•
Temp sensor
This simplifies the calculation of dynamic viscosity to
µ = f{(piston travel length)×(gap : piston to chamber2)×(travel
time)}.
Sensor Shown in Process Line
© 2010 Cambridge Viscosity, Inc
Coils
VISCOlab PVT Viscometer Overview
Key system characteristics
Pressure transducer
High-pressure
viscosity sensor
Isothermal control with
sensor, bath, and
encasing blanket
•  Integrated sensors
• Viscosity
• Temperature
• Pressure
•  Fully enclosed system for
temperature control
•  Minimum sample volume
•  Repeatable by design
•  Easy piston range changing
© 2010 Cambridge Viscosity, Inc
VISCOlab PVT Single Integrating Interface
Traceable pressure and temperature
(PCV) compensation
On-screen statistical analysis
of test conditions
Single-click temperature
set
User-configurable
dashboard and automatic
storage of test data
© 2010 Cambridge Viscosity, Inc
Cambridge Development Directions
Recent sensor enhancements
•  Easy piston change with low-torque sealing system
•  Optional flow-through attachment for oven-based systems
Recent system developments
•  Extended pressure and temperature capabilities
•  Improved gas capabilities
© 2010 Cambridge Viscosity, Inc
Recent Enhancements for Current Sensors
Easy piston change with low-torque sealing system
Flow-through attachment for oven-based systems
© 2010 Cambridge Viscosity, Inc
Extend Instrument’s Temperature and Pressure Capability
40,000
Pressure,
psi
20,000
Currently
available
option
Not yet
available
Standard
Cambridge
product
Currently
available
option
190
Temperature, degC
© 2010 Cambridge Viscosity, Inc
300
Expand Gas Capabilities
•  2001: Initial proof of concept to extend to gas range (0.02–0.2 cP)
•  2005: Supported industry requests to extend availability
•  2008: CVI began calibrating gas range with N.4 (Hexane) and CO2
•  2009: Researchers report repeatable gas results
•
University of Calgary, IPN, Clemson, Aramco
•  Next steps:
•
© 2010 Cambridge Viscosity, Inc
Extend industry findings
Pressure and Temperature Standards
•  Instrument calibration is necessary.
• Critical sensor feature: annular space between piston and chamber wall
• Space to increase with temperature and/or pressure
•  Compensation factor based on
• Published data on fluids characterized by NIST and others
• Data to 20,000 psi and 150 degC, depending on the fluid and test, but limited by
viscosity, temperature, and pressure.
•  Compensation is based on best-fit correlations for
• Temperature and pressure (linear)
• Each piston range.
Fluid standards for extended pressures and temperatures are needed.
© 2010 Cambridge Viscosity, Inc
Traceable References >2 cP Lacking Above 10,000 psi
High-Pressure, High-Viscosity Measurements with Oscillating Piston Viscometer
40
Dodecane at 25C
NIST dodecane at 25C
S6 at 25C
S6 at 100C"
35
30
Viscosity, cP
25
20
15
10
5
0
0
5000
10000
15000
20000
25000
Pressure, psi
30000
35000
Characterization of NIST- traceable references boxed in red area
VISCOlab PVT measurements for Dodecane and S6
© 2010 Cambridge Viscosity, Inc
40000
45000
Summary: Viscometer State-of-the-Art
VISCOlab PVT:
•  Developed to meet industry requirements for:
•  Accuracy
•  Small sample size
•  Pressure and temperature
•  Ease of use
•  Continued enhancements for developing
needs
industry
•  The lack of appropriate viscosity reference standards is
becoming a more acute problem as pressure and
temperature requirements increase.
© 2010 Cambridge Viscosity, Inc