Alarm Management Experience on Shearwater Dave Gisby and Ian Dunsmuir Shell U.K Exploration and Production
Contents • Overview of the Shearwater project • Alarm system configuration • Alarm system performance and operating benchmarks • Alarm Configuration Manager (ACM) usage • Summary and Conclusions
Shearwater Shearwater Co-Venturers
Shearwater Location
Shearwater Aerial View
Shearwater Overview • Shell/Exxon-Mobil/BP North Sea offshore installation • Defined as HP/HT production • First Condensate / Gas Oct 2000 • Production Conditions - 850 Bar THP - 190 DegC • 6 well-slot bridge linked installation to Main Topsides • Capacity: – Gas 11,600,000 m3/d (410 million Scfd) – Condensate 18,400 m3/d (116,000 BPD) – Gas Export Quality = Domestic quality
Shearwater Process Flow Sheet Gas Export 410 MM scfd Meter cool A T M I E cool N G E LT HEXS Regen Regen Turbo expander/ NGL o/head re-compressor compression LP/MP compression LT separator NGL 1st stage stabiliser heat Condensate Export 90,000 bpd heat 2nd stage Meter
Contents • Overview of the Shearwater project • Alarm system configuration • Alarm system performance and operating benchmarks • Alarm Configuration Manager (ACM) usage • Summary and Conclusions
Intelligent Alarm Management Studies have identified Three main Problem Areas • Too many alarms with too High Priority • Excess Standing Alarms • Alarm Flood Effects During Process Upsets
Alarm Prioritisation By Consequence • Three Pass Study 1. Personnel Safety 2. Financial Loss 3. Environmental Damage • Highest single classification determines alarm priority and classification
Standing Alarms • Studies have shown that 90% of standing alarms are due to incorrect system configuration and Poor alarm Strategy: – Incorrect Use of Off-Normal Alarming Facilities – Alarms Still Enabled on Out of service Equipment – Alarms Still Enabled on Known Faulty equipment
Alarm Flood • Alarm Flood Effects directly attributable to the normal shutdown of equipment • Alarm Flood Occurs at worst possible time for CRO • Alarms should only be valid when equipment is running • Intelligent alarm annunciation Strategy required • HSE have identified “alarm flood” as an issue when investigating incidents
Alarm Prioritisation - History • Priorities defined using Shell Expro tool for all alarms and implemented Oct 2002 • Database – 22,800 alarms: – Emergency - 136 – High - 3876 – Low - 7839 – Journal – 10,949 – Above defined in database as Px, P3,P2 and P1 respectively • Two panel operators normally • Future – one operator normally and two for Start-Up
Alarm Database Total number of configured alarms 9000 7839 8000 7000 Number of alarms 6000 5000 3876 4000 3000 2000 1000 136 0 Low Priority (P2) High Prority (P3) Emergency (Px)
Contents • Overview of the Shearwater project • Alarm system configuration • Alarm system performance and operating benchmarks • Alarm Configuration Manager (ACM) usage • Summary and Conclusions
Alarm Performance - History • Database – 22,800 alarms • Bad actors (events) being worked on a weekly basis. • Alarm activations: – 1200 per hour (Sept 2001) – 370 per day (Sept 2002) – 288 per day (March 2003) • Standing alarms: – Emergency 12, High 200, Low 140 (Aug 2002) – Emergency 2, High 71, Low 184 (Oct 2002) – Emergency 0, High 26, Low 60 (Feb 2003)
Standing Alarm History Standing alarms 200 180 Number of alarms 160 140 Emergency 120 100 High Priority 80 Low Priority 60 40 20 0 Pre Alarm Post Alarm 6-Jan-03 14-Mar-03 Target Database Database
Alarm Classification - Now • CP – Change Process being used as vehicle for funding • 30 Consoles in ACM = 30 TPS Units in use • Issue with Low and Journal alarms due to sub picture design. • Sub picture change to allow alarms to be journalled and be seen on graphics.
Alarm Classification – Next Steps • Complete remaining consoles including F&G • Review bad actors on a weekly basis and after trips using “Event Analyst” • “User Alert” to be integrated into alarm management • Alarm flooding hierarchy i.e. equipment trip, package trip, SPS, - being investigated
SGS Benchmark Number of configured alarms per operator (Fire & Gas and Journal alarms excluded) 4500 4000 3500 3000 2500 2000 1500 1000 500 0 Shearwater On-shore gas Complex refinery Shearwater target processing unit unit
Contents • Overview of the Shearwater project • Alarm system configuration • Alarm system performance and operating benchmarks • Alarm Configuration Manager (ACM) usage • Summary and Conclusions
Why use ACM? • ACM allows the active alarm configuration to be monitored and controlled. • The alarm “enforcement” process and reports gives the operator a good view of the current alarm configuration. • The Master Alarm Database contains an audit trail of all parameter changes – particularly useful if a trip point is being frequently changed. • The underlying ACM equipment model allows groups of points to be managed separately (e.g. to disable alarms for shutdown equipment).
ACM Configuration NT/2000 NT/2000 NT/2000 Master Alarm Database Alarm ACM Manager Administrator Alarm Client Client Manager Server Process Control Note that Network NT/APP NT/GUS Alarm multiple Enforcer Alarm Server functions Enforcer Client TPN Server can CL Server coexist in AM one box Process Network
Overview – Console + Operating Unit Honeywell TDC3000 Control System Console(1) Console(2) Console(3) Console(34) Process Unit WA Process Unit CI Process Unit CW Process Unit GS Well SWA01 P4831 Booster Pump Well SWA04 P4821 Booster Pump Well SWA08 C2110 Contactor
Alarm Flood Low Discharge Low Flow Press Alarm Alarm DCS Low Discharge Low Flow Pressure ESD Trip ESD Trip ESD PT PT FT FT STOP
Dynamic Alarm Suppression ACM DCS Local Stop Activated ESD PT PT FT FT STOP
ACM Usage • System being used to ensure alarms are controlled. • If alarm found to require re-prioritising then change process offshore used to provide trail. • Equipment Groups Configured to match Existing TDC3000 Keyword – Reduced Engineering Costs • Alarm Configuration Changes logged so are Auditable • Alarm Enforcement can be carried out either on demand or periodic scheduled activity • Wish to be able to Import / Export the database
Contents • Overview of the Shearwater project • Alarm system configuration • Alarm system performance and operating benchmarks • Alarm Configuration Manager (ACM) usage • Summary and Conclusions
Summary and Conclusions • ACM Enabled control to be placed on the PCS Alarms. • Change process required to re-prioritise Alarms • ACM software added to mask Standing Alarms • ACM software added to mask Dynamic Alarms • All Changes to ACM database are logged and are auditable • Alarm Enforcement history and changes are available to view as post event reports
Acknowledgements • Honeywell, Aberdeen office for its commitment to the challenging quantity of alarms for masking. • Shell Expro, Exxon-Mobil and BP for Approval of this presentation
Alarm Classification By Consequence J0 R0 NO ALARM START SLE0 J1 JOURNAL R1 A1 LOW SLE1 A2 HIGH SLE2 SLE3 EMERGENCY SLE4
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