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Paraffin buildup in flowlines and interface complicates field
operations
A customer operating in the Ogston field of central Alberta produces
primarily from the Granite Wash, Slave Point, and Keg River Formations. The
customer had been experiencing paraffin deposition in lease flowlines, a common
occurrence in the area. Despite a paraffin deposition program in lease
flowlines, the operator was reporting an increase in wax volumes collected
during the pigging process. Additionally, a pad was forming at the interface of
the FWKO flowline.
Schlumberger conducted a system review that included interface sampling
and performance testing to select a qualified paraffin solvent product.
Atmospheric conditions included temperatures ranging from 10 to 25 degC [50 to
77 degF] and pressure of 2.6 MPa [377 psi]. Field production was
1.2-m3/d [7.6-bbl/d of oil equivalent] natural gas,
30.3-m3/d [190.6-bbl/d] oil, and 771-m3/d [4,849-bbl/d]
water.
PI-7302 dissolver tested and selected to dissolve paraffin buildup
Laboratory solvency tests performed on a deposit sample indicated that
PI-7302 paraffin dissolver was the most effective at dissolving the deposit.
The test results confirmed the success of the previous application of PI-7302
dissolver that was batched into flowlines when the FWKO experienced issues.
Following testing, PI-7302 paraffin dissolver was applied continuously
at a rate of 1,800 ppm at two satellite locations upstream from the FWKO
interface. Another injection point was established at the FWKO inlet at 3,000
ppm to avoid wax deposition on flowlines going into the treater. This flowline
program supplemented a downhole paraffin dispersant application already in
place. A solvent batch program was discontinued.
Dissolver reduces paraffin in pig returns and eliminates depositions at
FWKO interface
The application of the PI-7302 dissolver reduced paraffin in the pig
returns and eliminated it at the FWKO interface. A continuous program of
applying PI-7302 dissolver was initiated, and since then, neither the flowlines
nor the interface has experienced paraffin issues.
