Presentation on theme: "Risk management and assessment for business Advances in Process Control 9 20 September 2011, York, United Kingdom."— Presentation transcript:
risk management and assessment for business Advances in Process Control 9 20 September 2011, York, United Kingdom
Advances in Process Control 9 Jasjeet Singh Are Blowout Preventers and Fire & Gas Systems ready to be classified as Safety Instrumented Systems on offshore installations? Presented By: Jasjeet Singh MCMI, AMIChemE, MBA, BE (Chemical) Senior Engineer, Risktec Solutions Limited
Advances in Process Control 9 Jasjeet Singh Objectives Introduce briefly to Blowout Preventer (BOP), and Fire and Gas Systems (FGS) in offshore oil & gas installation context; Simplistically evaluate the Safety Integrity Level (SIL) these systems would be expected to achieve; and, Discuss if these systems should be designated as Safety Instrumented Systems (SIS); Discuss “challenges” in upgrading BOP and FGS to SIS status.
Advances in Process Control 9 Jasjeet Singh Functional Safety Definition What is Functional Safety? The industry standard IEC 61511 defines it as “Functional safety is part of the overall safety that depends on a system or equipment operating correctly in response to its inputs.” Example: An over-temperature protection device, using a thermal sensor in the windings of an electric motor to de-energise the motor before they can overheat, is an instance of functional safety. Specialised insulation to withstand high temperatures is not an instance of functional safety (although it is still an instance of safety and could protect against exactly the same hazard).
Advances in Process Control 9 Jasjeet Singh Basic SIS Configuration Sensor Elements Pressure Temperature Flowrate Composition Logic Control Safety PLC Relay Logic Final Elements Valve Assemblies Circuit Breakers Power Drives Secondary Systems
Advances in Process Control 9 Jasjeet Singh Systems under the Scanner Blow Out Preventer Fire and Gas System
Advances in Process Control 9 Jasjeet Singh Blow Out Preventer A Blow Out Preventer (BOP) is a combination of several valves installed at the wellhead. Function: Prevention of escape of well fluids from primary containment BOP Typical Location: Beneath the rig for land rigs; At the water’s surface on jack-up rigs; On the seafloor for floating offshore rigs. What is a Blow Out Preventer?
Advances in Process Control 9 Jasjeet Singh What a BOP Looks Like…
Advances in Process Control 9 Jasjeet Singh Simplistic LOPA on a BOP System Scenario Unexpected release of high pressure gas in the reservoir into the well causing abnormal and sudden increase in riser pressure. Potential for release of high pressure oil / gas jet at the platform from the well (Blow- Out). ConsequencesMultiple fatalities from fire & explosion on the installation; MATTE Target Frequency Factor6 (equivalent to 10 -6 per year) Initiating EventUnexpected well pressure due to accumulated gas Initiating Event Frequency Factor 3 (equivalent to 1 in 1000 well sites) Conditional ModifiersIgnition Control – 0 (No credit) Exposure – 0 (No credit)
Advances in Process Control 9 Jasjeet Singh Simplistic LOPA on a BOP System Independent Protection LayersRisk Reduction Factor BPCS Indication of pressure in the control room and process shut down 1 Alarms Linked to the BPCS system – Not Independent 0 Mitigated Event Factor (6) – (3) – (1)2 Required SIL for chosen SIF2 Hence the “BOP System” may be required to meet SIL 2 requirements.
Advances in Process Control 9 Jasjeet Singh BOP Control System Primary Functions: To ensure that sufficient hydraulic pressure is conveyed to the BOP assembly when a demand is placed; Ensure that the sequence of valve activation is executed as per design; Elements: Pressure measurement devices (an array of pressure transmitters / switches at different strategic locations) Logic Control (Sub sea modules and on Topsides) Final Elements (The BOP assembly - Actuators & Valves) Support Elements (Hydraulic Power Unit)
Advances in Process Control 9 Jasjeet Singh Typical BOP System
Advances in Process Control 9 Jasjeet Singh Challenges in upgrading BOP to SIS Status Technical Challenges: Complex System – An array of devices including multiple sensors Manufacturing high integrity equipment for subsea environment Operation and Maintenance Challenges: Proof Testing as per requirements of the Standard “End to End” tests in operation are not feasible - Destructive nature of final elements Maintenance of equipment under harsh & corrosive environment Compliance / Standards related Challenges: Human in the loop – limited reliability issues Same Equipment – Different Requirements
Advances in Process Control 9 Jasjeet Singh PHASE 11 – Safety Life Cycle Structure and Planning (IEC 61511-1 Clause 6.2) PHASE 1 Hazard and Risk Assessment PHASE 2 Allocation of Safety Functions to Protection Layers PHASE 3 SIS Safety Requirements Specifications PHASE 4 SIS Design & Engineering PHASE 5 SIS Installation, Commissioning & Validation PHASE 6 SIS Operation & Maintenance PHASE 7 SIS Modification PHASE 8 SIS Decommissioning IEC 61511-1 Clause 8 IEC 61511-1 Clause 9 IEC 61511-1 Clause 10, 12 IEC 61511-1 Clause 11, 12 IEC 61511-1 Clause 14, 15 IEC 61511-1 Clause 16 IEC 61511-1 Clause 17 IEC 61511-1 Clause 18 PHASE 10 – SIS Functional Safety Assessment (IEC 61511-1 Clause 5) PHASE 9 – SIS Verification (IEC 61511-1 Clause 7, 12.4 and 12.7) STAGE 1: Analysis Stage STAGE 2: Realization Stage STAGE 4: Management and Planning Stage STAGE 3: Operations and Maintenance Stage SIS Safety Life Cycle – Where will a BOP cause issues
Advances in Process Control 9 Jasjeet Singh Regulator’s Position United Kingdom HSE Offshore Division’s Guide GASCET (April 2006) includes BOP as one of the devices for which a functional safety assessment is recommended using: UKOOA Guidelines for Instrument Based Protective Systems IEC 61508 IEC 61511 NorwayUnited States AustraliaMiddle East - South Asia -
Advances in Process Control 9 Jasjeet Singh Fire and Gas System Fire and Gas ‘Detection’ Systems Three principal types of detectors commonly in use on off-shore installations: Heat, Flame & Smoke Flammable Gas Toxic Gas Fire and Gas System – ‘Final Elements’ HVAC System Emergency Shut Down Sequence Initiation Shut Off / Isolation Valves Blowdown and Depressurisation System
Advances in Process Control 9 Jasjeet Singh Simplistic LOPA on a FGS ScenarioRelease of flammable gas. Potential for jet fire / VCE. ConsequencesMultiple fatalities from fire & explosion on the installation Target Frequency Factor6 (equivalent to 10 -6 per year) Initiating Event10” gas pipeline failure due to vessel impact Initiating Event Frequency Factor 3 Conditional ModifiersIgnition Control – 0 (No credit) Exposure – 0 (No credit)
Advances in Process Control 9 Jasjeet Singh Simplistic LOPA on a FGS Independent Protection LayersRisk Reduction Factor BPCS Process shut down. Isolation of pipeline from nearest isolation valves. 1 AlarmsNon - Independent Alarms0 SRPSTemporary refuges & escape crafts1 Mitigated Event Factor (6) – (3) – (1)1 Required SIL for chosen SIF1 Hence the “FGS” may be required meet SIL 1 requirements.
Advances in Process Control 9 Jasjeet Singh Challenges in upgrading FGS to SIS Status Technical Challenges: FSG is also a complex system and is linked with the Emergency Shutdown System FSG is a combination of a number of loops – multiple SIFs with different SIL requirements Operation and Maintenance Challenges: A large amount of kit to be maintained Compliance / Standards related Challenges: Usual suspects
Advances in Process Control 9 Jasjeet Singh BOP and FGS as SIS – The Two Sides AgainstFor Field devices and technologies are fundamentally different … But the devices are available, and are being developed… Not be considered performing a critical safety function… They do. ESD is only part of the overall safety & risk control… IEC 61508 is not applicable…Covers all E/E/PE systems... Too costly…Not more than cost of an accident… Difficult to materialise … Effort should be made – necessity is mother of invention… Regulator does not want this…Post DwH, they do…mostly… Industry has been operating this way – Why now? Continuous improvement …
Advances in Process Control 9 Jasjeet Singh Recommendations Oil and gas industry should explore the possibility of upgrading the BOP and FGS to SIS. IEC, Industry and Regulators should red-define / amend the relevant requirements to clarify the issue. Design engineers and safety consultants should be aware of the issue and endeavour to improve the safety system.
Advances in Process Control 9 Jasjeet Singh Closing Remarks Not all safety systems are created equal and every installation has different performance, risks and financial goals to meet. Small regional operators are much less likely to make this step change in the way the BOP and the FGS are managed due to limited resources. It is up to global organisations to take this initiative, and raise standard of best practice in managing these systems.
Advances in Process Control 9 Jasjeet Singh Thank You for Your Attention