Reduce risk of asphaltene deposits
Two fields located in approximately 90-m water depth in the UK sector of
the North Sea were developed using subsea tiebacks connected to an existing
platform, with independent flowlines for produced fluids from each well. One of
the treated fields typically produced 4 MMcf/d of gas with 3,000-bbl/d dry oil;
the other field typically produced 30-MMcf/d gas with 1,700-bbl/d condensate
and 350-bbl/d water. Because these fields’ production commingled with
oil, gas, and condensate from other fields in the separators located on the hub
platform, they were identified as being at risk of asphaltene deposition.
The operator required an effective, environmentally acceptable
asphaltene inhibitor. In addition to high-quality performance, compatibility
with materials of construction in the umbilical used to inject the product was
considered critical. The operator needed to assess multiple solutions for
suitability in the pipeline system exporting the crude.
Prevent buildup with effective, biodegradable asphaltene inhibitor
Schlumberger recommended PI-7595 asphaltene inhibitor for this
application. Based on performance testing, the operator shortlisted the
inhibitor as one of the two most effective products. In third-party testing,
PI-7595 inhibitor exhibited superior compatibility with the umbilical materials
of construction. In addition, PI-7595 inhibitor achieved a gold
rating—the highest environmental category of all evaluated products.
Based on these factors, the operator selected PI-7595 inhibitor for application
in these fields.
Mitigated risk of asphaltene deposition in subsea equipment
PI-7595 asphaltene inhibitor was injected continuously into the subsea
riser on one field and downhole on the other. Since field startup, the product
has successfully prevented any significant asphaltene deposition in the
commingled topside fluids as demonstrated by no asphaltene blockages of pumps
or filters and no significant turbidity observed in a formulation stability
test.
