TOPIC 3: Wax Deposition
6
©H
ERIOT
-W
ATT
U
NIVERSITY B41OA December 2018 v3
3.3.1 Pressure Loss; High Viscosity
High viscosity and wax deposition on pipe surfaces are major reasons of high
flowline pressures – the crystallisation of wax suddenly
increases crude fluid
viscosity due to the gel forming tendency of the crystals.
Another factor, leading to an increased pressure loss (and
a reduction in
effective capacity of the line), is the deposition of wax on the pipe wall. This
both reduces the effective pipeline diameter while, at the same time, increases
the pipewall roughness.
Sometimes the increase pressure loss (and the reduction in flow capacity) may
cause crude transportation to stop altogether.
The mechanism here is that
high pressure loss across the tubing causes: low flow rates of the well; this in
turn
leads to lower temperature; thus, the conditions
for wax deposition are
more favourable (because of reduced fluid temperature); further reductions in
flow rate and temperature can follow – eventually production may stop.
Dostları ilə paylaş: