Oil & Natural Gas Projects
Exploration and Production Technologies
Paraffin Deposition Research and Model Validation
This project was selected in response to DOE's Oil Exploration and Production
solicitation DE-PS26-01NT41048 (focus area: Reservoir Efficiency Processes).
The University of Tulsa planned to use its state-of-the-art test facilities
to gather single- and multi-phase flow data to enhance the capabilities of their
paraffin deposition model (TUWAX). The work focused on three projects: 1) conducting
single-phase flow tests to more accurately model single-phase deposition, 2)
conducting two-phase flow tests to model two-phase deposition, and 3) focused
experiments to determine deposition physics and the effects of water.
University of Tulsa
Generating single- and two-phase paraffin deposition data that were used to
update and validate the TUWAX program.
Improved technology in the area of paraffin deposition modeling will play a
significant role in reducing operating costs for oil and gas production. The
single-phase and multi-phase deposition models generated in this project are
being used by industry as a basis for designing prevention and remediation techniques
as well as in the design of facilities to bring in new reserves. Remediation
costs are on the order of $1 million at water depths of 400 meters, but the
cost is proportionately greater as development depths increase. Being able to
predict deposition has helped companies optimize the design of prevention programs,
thereby minimizing or eliminating remediation costs for these projects and resulting
in cost savings for the operators.
The improvements to the prediction model have provided engineers a degree of
confidence when scaling up to larger-diameter pipes, a predictive model that
is less dependent on a single oil and a model that can predict paraffin deposition
in oil-water systems.
The frontier for oil and gas exploration and production is deepwater; however,
as oil and gas production moves to deeper and colder water, subsea multiphase
production systems become critical for economic feasibility. It will also become
increasingly imperative to adequately identify the conditions for paraffin precipitation
and predict paraffin deposition rates to optimize the design and operation of
these multiphase production systems. Accurate information about the potential
for and extent of wax deposition is very critical, not only for the operation
and design of these systems, but also for assuring their economic feasibility.
Although several oil companies have paraffin deposition predictive capabilities
for single-phase oil flow, these predictive capabilities are not suitable for
the multi-phase flow conditions encountered in most flowlines and wellbores.
DeepStar was formed to identify and develop the required technology. A $4.5
million joint industry partnership to investigate paraffin deposition at the
University of Tulsa was formed in May 1995 and is a spin-off from DeepStar.
Three major studies were conducted. The key findings from these studies are:
- Deposition Physics Studies. A new facility was constructed to investigate
long-term paraffin deposition behavior. Ten single-phase, long-term deposition
tests were completed in the three test sections, with diameters of 0.5, 1.0,
and 1.5 inches and with testing durations of 3 - 27 days. A 27-day test was
conducted to investigate aging phenomena. Three oil-water two-phase tests were
conducted in the 1.5-inch test section with water cuts of 25%, 40% and 75%.
Two different crude oils were extensively studied under single-phase and two-phase
oil-water conditions to assess their deposition tendencies using the cold finger
- Single-Phase Studies. A total of 19 single-phase tests were conducted successfully
using a condensate fluid in two different flow loops and 12 tests with a heavier
oil. Tests with the more-viscous crude oils produced deposits with relatively
high oil content.
- Multi-phase Studies. Experimental heat transfer data were acquired on flow
pattern transitions for horizontal, upward 1° and upward vertical crude
oil-natural gas two-phase flow at high-pressure conditions. A total of 23 multiphase
(gas-oil) tests in horizontal and vertical pipes were conducted to generate
wax deposition data. Wax deposition was found to be a flow-pattern-dependent
The TUWAX model was enhanced to incorporate Venkatesan's (2004) model and
the Singh et al. (2000) model. TUWAX was validated with a well-defined database.
A test facility was constructed to study the shear prevention/removal and
aging effect during the wax deposition process for turbulent-flow conditions.
Follow-on funding was provided via DOE membership in the TUPDP joint industry
project from May 2004 to May 2005.
Matzain, A., Creek, J.L., Apte, M.S., Zhang, H.Q., Volk, M., Redus, C.L.,
and Brill, J.P., Multiphase Flow Wax Deposition Modeling, ETCE2001-17114,
proceedings from the ASME Energy Technology Conference and Exhibition, Houston,
TX, February 5-7, 2001.
Hernandez, O.C., Sarica, C., Brill, J.P., Volk M., Delle-Case, E., and Creek,
J., Effect of Flow Regime, Temperature Gradient and Shear Stripping in Single-Phase
Paraffin Deposition, Presented at 11th International Conference Multiphase
03, San Remo, Italy, June 11-13, 2003.
Manabe, R., Wang, Q., Zhang, H.Q., Sarica, C., and Brill, J.P., A Mechanistic
Heat Transfer Model for Vertical Two-Phase Flow, SPE 84226, Presented at the
2003 SPE Annual Technical Conference and Exhibition, Denver, CO, October 5
- 8, 2003.
DOE Final Technical Report, April 2001-March 2004, "Paraffin Deposition and
Model Development" [PDF-1.93KB], June 2004
Manabe, R., Wang, Q., Zhang, H.Q., Sarica, C., and Brill, J.P., A mechanistic
heat transfer model for horizontal two-phase flow, Proceedings from the 4th
North American Conference on Multiphase Technology, June 3-4, 2004, Banff,
Hernandez, O.C., Sarica, C., Volk, M., Brill, J.P., Delle-Case, E. and Hensley,
H., Improvements in Single-Phase Paraffin Deposition Modeling, SPE 84502,
SPE Production & Facilities Journal, November 2004.
Project Start: April 1, 2001
Project End: March 31, 2004
DOE Contribution: $1,200,000
Performer Contribution: $1,236,980 (51% of total)
Other Government Organizations Involved: Minerals Management Services
NETL - Sue Mehlhoff (email@example.com or 918-699-2044)
U. of Tulsa - Cem Sarica (firstname.lastname@example.org or 918-631-5154)
Tulsa University paraffin deposition projects small-scale test facility.
Tulsa University paraffin deposition projects multi-phase test facility.