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The Stim-Lab Rheology and Proppant Transport Consortium began in 1988 as CEA#1,
or the first joint industry project supported by the Completions Engineering
Association. It has grown from 15 to 30 members, which include oil and gas
producers, service companies and suppliers. Previous work includes the rheology
and transport of common fracturing fluids under realistic downhole conditions
and observations of the proppant carrying capacity of the fluids after shear
history.
Special equipment has been designed and manufactured to accommodate the studies.
Videotapes have been made to document the observed proppant transport in
crosslinked fluids vs. fluid type, pH and amount of breaker. The highlights are
summarized in a recently prepared tape of past observations. Fluids include guar
and HPG + borates vs. pH, gel concentration and breaker, CM1HPG + Zirconium
fluids, Gelled oils, and foams vs. time at temperature.
These observations have been useful to members in selecting fluids and
conditions that insure proppant transport. Other highlights include, the
measurement of the impact of proppant size and type on fluid rheology and/or
pressure drop down the fracture, the development of correlations to predict the
bridging of proppant across natural fractures and other high leakoff areas, the
impact of tortuosity on pressure drop down the fracture vs. fluid type.
Correlations have been developed to predict proppant transport based on measured
fluid properties.
Work in 1999 is Concentrating On
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Predictive Correlations
Correlations are being developed to predict the viscosity of crosslinked gels as
a function of gel type and concentration, crosslinker type and concentration,
breaker type and concentration, temperature and shear history. Fluids are
measured are on conventional rheometers, viscoelastic measuring systems and in
large-scale pipe and slot devices. The fluid properties are related to observed
transport behavior on new and previous fluids.
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Numerical Simulations
In conjunction with the University of Minnesota a 3D fluid flow model will be
developed to examine the impact of various fluid properties such as
viscoelasticity and shear thinning behavior upon 3D-proppant transport.
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Downhole Heat Transfer
Current heat transfer programs are based on water and thus may be in error.
Large-scale experiments will be conducted to simulate the effect of downhole
temperature on the heat-up of fracturing fluids in the presence of filtercake.
Base gels and crosslinked gels will be tested to develop correlations that can
predict temperature of hydraulic fracturing fluids at various positions in the
fracture. The effect of temperature on the fluid viscosity will then be
evaluated. These correlations can be used to better design and select a proper
fracturing fluid for a known formation based on the change of viscosity as a
function of fluid temperature vs. time.
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Completion of Database
A database is being developed that includes rheological properties of all the
fluids that have been tested at STIM-LAB. The database will be searchable by
fluid type and conditions.
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Development of a Program to Predict Viscosity
The developed Excel program PredK will be able to predict viscosity of
fracturing fluids as a function of polymer concentration, crosslinker
concentration, breaker type and concentration, shear history, and temperature.
The program can be used by the engineer to select the fluid type and gel
concentration to insure adequate proppant transport and allow cleanup of the
proppant pack in a desired period of time.
Facts:
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Meetings held twice per year to discuss previous six month's studies.
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Last twelve month's information available to members through website.
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Previous data available to new members.
Stim-Lab encourages new members so that research continues adding value to
participating company's lines of business.
Contact
Us
for membership information.
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