pra application to offshore drilling critical...

Massoud (Mike) Azizi

Principal Engineer/ Technical Fellow

Aerojet Rocketdyne Extreme Engineering

PRA Application to Offshore Drilling Critical Systems

This document does not contain ITAR or EAR technical information

1

Outline

• PRA Methodology

• Applications of PRA to nuclear industry

• Applications of PRA to aerospace industry

• How can PRA be applied to oil & gas industry

• Macondo Accident Scenario

• PRA Methodology Comparison

• PRA management

• Conclusions


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Probabilistic Risk Assessment

A quantitative evaluation of system safety

• Identification, selection, and screening of initiating events

• Definition and modeling of all scenarios

• Initiating and pivotal events modeling

• Data development and risk quantification

• Uncertainty analysis

• Risk importance ranking for risk reduction and communication

Fault Trees Event Trees

A systematic and comprehensive methodology

to evaluate risks associated with complex

engineering and technological systems.


PRA

MLD = Master Logic Diagram

CDA = Comparative Design Assessment

RBD = Reliability Block Diagram

FDIR = Failure Detection, Isolation and Recovery

PRA = Probabilistic Risk Assessment

SPF = Single Point Failure

System Identif ication/ Success Criteria

Historical/ actual data

Generic data

CDA

Failure rate database

FMECA

List of Initiating Events

Fault Tree Analysis

Functional Event Tree

Systemic

Sequence Quant./ Cutset Analysis

Uncertainty Analysis

Feedback into design/Ops/

Maint.

RBD Prediction/ Trade

SPF Analysis

Safety Hazard Analysis

Common Cause Failure Analysis

Maintainability/ Availability

FDIR

Operability/ Ops. Support

Reliability Testing based on; 1. prediction, 2. Criticality/hazard causes, 3. Minimal cutsets

MLD

PRA Methodology and Applications

Uncertainty Analysis

Master logic Diagram

http://en.wikipedia.org/wiki/File:Fault_tree.png

3

Application of PRA to Nuclear Industry


Three Mile Island Nuclear Station

4

Event and Fault Tree Analyses


5

Application of PRA to Aerospace Industry


Space Shuttle Challenger Accident

Space Shuttle Challenger

The essence of aerospace PRA

6

Payload Nuclear Safety


Mars Science Lab Rover Curiosity

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PRA Application to Offshore Drilling Rig Systems


Rig surface systems:

•Gantry Crane

•Riser Elevator

•Draw Works

•Dynamic Positioning

•Etc.

Rig subsea and well control

systems

•Blowout Preventer (BOP)

•Lower Marine Riser

Package (LMRP)

•Mud Flow System

•Etc.

PRA methodology can be applied to

Oil & Gas Systems to identify:

• Likelihood of undesired events

• Severity (magnitude) of the consequences

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PRA Methodology can Help Identify Potential Accident Scenarios


Macondo accident scenario could

have been identified using PRA

methodology

9

Deepwater Horizon Sample Functional Event Tree*


* Based on information provided in the BP Deepwater Horizon Accident Investigation Report, 9/8/10

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Comparison of PRA Applications across the Different Industries


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PRA Management Among Different Industries


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Conclusions


• A standard risk management approach such as PRA will be able to help oil and gas industry, especially offshore oil drilling improve safety and reduce hazard risk

• PRA analysis for offshore drilling and production operations (as well as onshore) can benefit from the nuclear and aerospace industries past experience

• Oil and gas regulatory agencies (e.g., BSEE) can identify target frequencies for consequences such as:

– Loss of rig due to fire/explosion

– Severe release of hydrocarbons to the environment

• Oil and gas Industry representative agencies such as API can develop failure rate databases that can be used by the entire industry and utilized in the oil rig PRA

pra application to offshore drilling critical...

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