70 years anniversary seminar and celebration for professor

Working together for a safer world

Risk analysis of marine operations involving dynamic positioning

Dr. Haibo Chen

20 May 2014

70 years anniversary seminar and

celebration

for

Professor Odd M. Faltinsen and

Professor Torgeir Moan

©Lloyd’s Register Consulting

Haibo Chen – Who am I ?

• 1999 – 2003, Dr.ing study supervised by

Prof. Torgeir Moan

• 2003, Joined Scandpower AS

• 2005, relocated to Scandpower Inc. in

China in. Live and work in Beijing, China

since then.

• 2006 – present, President of Scandpower

Inc. in China.

• 2010, became part of Lloyd’s Register

since. Managing Director for Lloyd’s

Register Consulting Asia since 2013.

• A risk analysis professional, 15 years on

safety of marine operations involving

dynamic positioning.


Dr.ing: FPSO and shuttle tanker collisions (1999 – 2003)

• "Probabilistic Evaluation of FPSO-Tanker

Collision in Tandem Offloading Operation“, IMT-

Report 2003:1, Dept. of Marine Technology,

NTNU, January 2003. Reprinted in 2010.

• Fortunate to have wide co-operations with

industry, e.g. Statoil, Navion, SMSC, Kongsberg,

SINTEF, HSE(UK), and a few shuttle tanker

captains.

Bedre sikkerhet i Nordsjøen (17.3.03, 12:55)

Et doktorgradsarbeid ved Institutt for marin teknikk bidrar til økt

sikkerhet under lasteoperasjoner i Nordsjøen.

Offshore-industrien var sterkt representert under en doktordisputas på

Tyholt fredag. Haibo Chen forsvarte da sin avhandling "Probabilstic

Evaluation of FPSO-Tanker Collision in Tandem Offloading Operation".


A practical formulation of Risk Model for Marine Operations

• Accident: collisions, loss of well integrity,

rupture of loading hose, etc.

• Position loss: drive-off vs. drift-off,

frequency.

• Recovery: human intervention to

mitigate/avoid accident, or other automatic

safety systems to function.

• Automatic safety system, e.g. Drive-off

Preventer, Auto EDS, SDS system, etc.

P(position

loss)

P(failure of recovery)

P(accident) =

Frequency of position

loss

Failure probability of recovery actions

initiated by DP operator, or automatic safety

systems, given position loss.


How frequent had a position loss happened?

• Rule of thumb: 0.3 per year, 0.2

drift-off and 0.1 drive-off,

averaged for DP class 2+3

vessels.

• DP class 1 vessels?

• Frequencies in the chart have

very different DP operational

hours behind.


Position loss incident and DP time reporting

• Lack of a common DP incident reporting scheme on the NCS/worldwide

• SYNERGI

• WSOG logging

• DP watch checklist

• IMCA (vulnerary basis)

• Ambiguity contents or insufficient information in the reporting, and under reporting, a hidden unknown factor

• Major deficiencies to failure frequency and risk analysis: Missing reported vessel DP time

• Recommendation 1: to improve reporting of

DP incident and DP time.

• This may be linked to Well/location Specific

Operating Guideline.

• Enable better DP failure frequency data

• Recommendation 2: Differentiate types of

DP vessels in causal analysis. The same

applies for DP2 vs. DP3.

Environment

Thruster

DP-Control

Power

Key DP

Personnel

Incident Category Causal Areas

Advisory

Yellow

Red

DP Incidents

Loss of Position

Non Loss of

Position


DP failure frequency: from Generic to Vessel & Operations Specific

• Objective: vessel and/or DP

operational specific position loss

frequency.

• Challenge: Significant variations

among different risk analyses on this

element. Reasoning for adjustment

often not well documented.

• Experience from a DP flotel study

(2011-2013), methodology of

vessel/operations “adjustment

factors”.

• Recommendation 3: Need a systematic and

robust approach to handle “frequency

adjustment” in risk analyses.


Nature of DP operations and human machine dynamics

Monitoring & checking

80 %

Emergency Situation

ca. 1 %

Not Automated Task

19 %

Challenges:

Passive surveillance => Lose Situation Awareness => No early detection

Out-of-the-loop in system dynamics + commercial pressure => Difficult to act in time

• Recommendation 4: systematic human

reliability study to improve operator

performance.


How quick can DP operators react to drive-off?

DP Operator Reaction Time in Drive-off Scenarios

0

50

100

150

200

250

300

3 6 7 8 9 10 11 12 13 14 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 45 46 47 49 50 51 52 53 54 55 56 57 58 59

Simulator Observation Case ID

Tim

e (

s)

Decision & Execution Time

Detection Time

• Incident data, Expert judgment, 2001-2002

• DP captain questionnaire survey 2002

• Logging of DP operator reaction time

during offloading simulator training

(simulated drive-offs) in 2003-2006

Time to prevent collision in drive-off: 60 s

vs.

Mean Reaction time by DPO: 85 s


Risk analysis of direct offloading concept (2007 – 2011)

• Separation distance 200 - 250 m

• Weathervane with inherent safe heading

philosophy

• Heading pivot point

• Min. 150 m no entry zone

• DP shuttle tanker position loss!

• Towards installation = Collision risk

• Away from installation = Hose rupture

and oil spill risk

• Selected offloading concept for, e.g.

Goliat, Aasta Hansteen, etc.

150

m

250 m

Illustration drawing: The size and distance are not to scale.

Heading pivot point

hose

Wind

Fixed / Geostationary Offshore Installations

Zone 1Zone 2

Zone 1

Zone 2


Inherent operational safety barriers in direct offloading concept

• Shuttle tanker positioning

strategy = Not heading towards

installation (less than 1 hour

drive-off collision risk exposure

time vs. 20 hours)

• 250 m distance = Time window

for recovery action by tanker DP

operator is 3 minutes vs. 1

minute (80 m distance).

• Collision frequency can be within

1% of an equivalent tandem

offloading concept.

DP Operator Reaction Time in Drive-off Scenario

(2003-2006, 66 simulator observations)

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80 100 120 140 160 180 200

Time (s)

Pro

bab

ilit

y o

f R

eact

ion

wit

hin

Tim

e


Safety of DP drilling operations (2003 – 2007)

Objective: Improve safety of DP operations on mobile offshore drilling

units on the Norwegian Continental Shelf.


Barrier methodology to model and analyze DP drilling safety

1. DP incident data collection and analysis: drive-off due to satellite based position reference

system failures.

2. Modeling of barrier functions and barrier element

3. Investigate performance shaping factors for the human barrier (DP operator).


Summary: Questions in the industry ?

• What are risk elements involved in DP operations?

• Can a position loss happen? If so, how frequent? What are main contributors?

• What’s role for DP operators, causes to failure or last safety barrier?

• What are key areas for risk mitigation efforts?

• What should a risk analysis include, and where to further improve?


Answers: Learning in the past 15 years… (1999 – 2014)

1. Risk model for marine operations involving DP.

• P(accident) = P(position loss) x P(failure of recovery)

2. Minimize position loss events and frequency

• Recommendation 1: to improve reporting of DP incident and DP time.

• Recommendation 2: Differentiate types of DP vessels in causal analysis. The same applies for

DP2 vs. DP3

• Recommendation 3: Need a systematic and robust approach to handle “frequency adjustment” in

risk analyses.

3. Improve human intervention given position loss

• Recommendation 4: systematic human reliability study to improve operator performance.

Lloyd’s Register and variants of it are trading names of Lloyd’s Register Group Limited, its subsidiaries and affiliates.

Copyright © Lloyd’s Register Consulting. 2013. A member of the Lloyd’s Register group.

Working together for a safer world

Dr. Haibo Chen Managing Director Asia

T +86 1380-132-0200 E [email protected]

Lloyd’s Register Consulting

www.lr.org/consulting

mailto:[email protected]

70 years anniversary seminar and celebration for professor

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