Bell

KOP Ltd
Society for Underwater Technology
“ There’s something about Kristin”
Part 2 – Kristin HIPPS System
Allan Bell, Project Engineer, KOP Ltd
Kristin HIPPS System
Slide 2
Kristin Subsea Production Control System
N
P
N-101
P-101
S-101
S-102
R-101
R-102
S
Kristin SEMI
HIPPS SYSTEM LOCATION
R
Kristin HIPPS System
Slide 3
Risks and Challenges
High Pressure High Temperature
1035 bar (15000psi) and 180 C
Covered in Part 1 – KOP Challenges with Kristin – J an Herland
Subsea HIPPS designed for SIL 3 (IEC 61508)
Process Shutdown (PSD) designed for SIL 1 (IEC 61508)
System designed for direct connection to topside SAS
Safety Automated System to have direct connection to SCM
New interface required to conform to IEC 61508 SIL 1
See Part 3 – Kristin Subsea Control System – Bruce Gardner
Kristin HIPPS System
Slide 4
Kristin Flowline Pressure Protection
The Kristin project developed a robust and reliable solution for
protection against pipe/riser failure over pressure within the safety
zone of the host platform with 3 different safety systems:
Subsea PSD
Subsea HIPPS
PSV on Semi
Reduced cost
Reduced project risk
Reduced technology gaps
Kristin HIPPS System
Slide 5
Flowline Pressure Protection Logistics
1
PMV PWV
PCV
PT
Subsea PSD
System
To Manifold
From well
HIPPS
Control Logic
HIPPS
Valves
PT
T
PT
T
2
From well To Flowline
SSIV
3
RISER
PSV
500 bar 330 bar 740 bar
~70m
Kristin HIPPS System
Slide 6
HIPPS Design Criteria
Safety Integrity Level : SIL 3
Critical Safety Unavailability : 5x10-4
Mode of operation : low
Demand Rate : 1 per year
Trip set point : 280 bar
Closure Time : < 12 seconds
Leakage Rate : < 0.1 kg/sec (740 bar)
Expected Operational Period : 5 years
Kristin HIPPS System
Slide 7
System Safety Integrity Level
Safety performance standard targets set at project outset in
accordance with IEC61508 and OLF guidelines
Pressure protection of flowlines and risers achieved by:
Subsea PSD SIL 1 CSU < 5x10
-2
Subsea HIPPS SIL 3 CSU < 5x10
-4
Riser PSV SIL 3 CSU < 1x10
-3
Isolation of well:
Subsea PSLL SIL 1
ESD (hydraulic) SIL 2
Kristin HIPPS System
Slide 8
HIPPS Schematic
Each flowline is protected by subsea HIPPS system on manifold
Dual 10”barrier valves
2oo4 voting of pressure transmitters
PFD Target: 5x10
-4
Achieved SIL3 PFD ~ 1.5x10
-4
Schematic:
Annulus Bleed
Methanol
PT PT PT PT
PT
Kristin HIPPS System
Slide 9
Equipment Under Control (EUC)
Complete SIL3 rated control loop located subsea
PT AIM
PT AIM
PT AIM
PT AIM
SAFETY
PROCESSOR
SDM
SDM
CV
CV
INITIATOR LOGIC SOLVER FINAL ELEMENT
SIL 3
Kristin HIPPS System
Slide 10
HIPPS Testing Regime
To meet the requirements of SIL3 the following test intervals are
defined:
Full Function Test: Proof test - 12 months
Pressure Transmitter Test: Auto test by methanol injection - 2 months
Barrier Valve Test: Partial closure test – 2 months
Control System Monitoring: Discrepancy monitoring – 24 hrs
Kristin HIPPS System
Slide 11
Process Shutdown System Integrity
PSD system initiators high accuracy PTT or topside initiated
Final elements are the tree valves
Logic contained in SAS PSD node
Subsea transport system including SEM and topside interface
included within boundary of PSD safety system
SIL justification confirmed to SIL 1 (PFD ~2x10
-2
) with 12 month
proof test
Kristin HIPPS System
Slide 12
Process Shutdown System Integrity
Data sources and SIL justification
Project safety organisation established
Independent safety authority
Individual FMECA performed at component level
Quantified with manufacturers data or published sources
– OREDA, NRPD, etc
Design review and audit
Functional Safety Assessment
Safety Audits
Sensitivity and architectural constraints analysis
Safety Analysis Report