Page 212 - Handbook Of Multiphase Flow Assurance

CHAPTER
8

Flow assurance stability issues

OUTLINE

Severe slugging 211 Calculation of slug impact force on
Phenomena description 211 Tees and Elbows 214
Prediction methods 212 Calculation of pressure surge on sudden
Suppression techniques 213
flow shut-in 215
Transient operation 213 Vacuum condition in flow 216
Shut-in and start-up 213
Rate ramp-up and ramp-down 214 References 216
Slugging in gathering lines 214 Further reading 216

Severe slugging

Phenomena description
The issue of severe slugging has several impacts on production system. Periodic slugging
causes mechanical integrity issues as slugs of liquid impact on bends of the flow lines. Slug of
a large volume may cause a production facility shutdown if it overfills the separator capacity.
Slug flow also causes periodic increase of backpressure on wells which reduces the overall
production rate and may lead to lower ultimate recovery of hydrocarbons from the reservoir.
A detailed description of severe slugging issues is provided by Hill and Wood (1994). The
authors provide the correlations for slug frequency, average and maximum possible slug
length and discuss the design of slugging systems.
The authors report the “best fit” average slug frequency correlation as:

( FsDVm)∗(10 .05 V ) ∗ D . 03 =−24 .729 0 .00766 exp
−
+
/
SG
( . 9 91209 ∗ Hle 1 0 068. /V )) + 24 721exp
(
∗
−
0
.
SL
. (
0 20524 Hle ( 10 068/V ))
∗
−
∗
.
SL
Handbook of Multiphase Flow Assurance 211 © 2019 Elsevier Inc. All rights reserved.
https://doi.org/10.1016/B978-0-12-813062-9.00008-7