HSEHealth & Safety

Executive

Accident statistics for Floating Offshore Units on the UK Continental Shelf 1980-2003

Prepared by Det Norske Veritas for the Health and Safety Executive 2005

RESEARCH REPORT 353

HSEHealth & Safety

Executive

Accident statistics for Floating Offshore Units on the UK Continental Shelf 1980-2003

Det Norske Veritas ASVeritasveien 1N-1322 Hovik

Norway

The main objective of the project is to obtain complete statistics (i.e. accident frequencies) foraccidents and incidents having occurred on floating units engaged in the oil and gas activities on theUKCS in the period 1980-2003. Floating units in this project are defined as comprisingsemisubmersibles, jackups, ships and tension-leg platforms engaged in drilling, accommodation,production and storage. The latter two types are classified as “floating” installations although they aredefined as “fixed installations” by the HSE under the Safety Case Regulations.

The results from this study will serve as a reference document for data to be used in future RiskAssessments of offshore floating units and furthermore, be a valuable reference document for UKHealth & Safety Executive (HSE)/ Offshore Safety Division (OSD) when reviewing Safety Cases.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Itscontents, including any opinions and/or conclusions expressed, are those of the authors alone and donot necessarily reflect HSE policy.

HSE BOOKS

ii

© Crown copyright 2005

First published 2005

ISBN 0 7176 6121 0

All rights reserved. No part of this publication may bereproduced, stored in a retrieval system, or transmitted inany form or by any means (electronic, mechanical,photocopying, recording or otherwise) without the priorwritten permission of the copyright owner.

Applications for reproduction should be made in writing to: Licensing Division, Her Majesty's Stationery Office, St Clements House, 2-16 Colegate, Norwich NR3 1BQ or by e-mail to hmsolicensing@cabinet-office.x.gsi.gov.uk

TECHNICAL REPORT

Table of Content Page

1 EXECUTIVE SUMMARY ..........................................................................................2 1.1 Background 2 1.2 Confidentiality 2 1.3 Objectives 2 1.4 Results 3

2 INTRODUCTION ........................................................................................................7

3 OBJECTIVES AND SCOPE OF WORK ....................................................................8

4 EXPOSURE DATA......................................................................................................9 4.1 Mobile offshore drilling units (MODUs) 9 4.2 Mobile Production Units (MOPUs) 10 4.3 Monohull units 12 4.4 Accommodation Units 14

5 INCIDENT REPORTING IN UK WATERS.............................................................15

6 OVERVIEW OF DATABASES ................................................................................16 6.1 ORION 16 6.2 MAIB 16 6.3 BLOWOUT 17 6.4 WOAD 17

7 EVENT CLASSIFICATION AND CODING PRINCIPLES ....................................18

8 ACCIDENT STATISTICS.........................................................................................20 8.1 Accident frequencies, all databases combined 21 8.2 Number of accidents for accommodation units 22 8.3 Occurrence frequencies, all databases combined 22 8.4 Number of occurrences for accommodation units 27

9 CONCLUSIONS ........................................................................................................29

10 REFERENCES ...........................................................................................................30

Appendix A Detailed Statistics

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1 EXECUTIVE SUMMARY

1.1 Background In 1999, during a project undertaken by DNV on behalf of the UK Health & Safety Executive (HSE), four databases holding information about UK Continental Shelf (UKCS) semi-submersible flooding incidents were interrogated. The survey revealed that that none of them had a complete recording of such incidents. In addition, it was identified that there were incidents which were not recorded in any of these sources. Consequently, the event frequencies being obtained varied with the availability of sources. There was no reason to believe that the situation and figures for other types of events on floating units should be any different. Hence, it was proposed to initiate a series of projects, but addressing all types of risks to floating units. The most recent one, Accident Statistics for Floating Offshore Units on the UK Continental Shelf 1980 – 2001, was completed in 2003. This current project updates the data of the previous project by two further years, 2002 and 2003.

1.2 Confidentiality In order to ensure that the final results of the project were accurate and in line with the Quality Control requirements of the DNV Consulting’s WOAD databank it was necessary to obtain "raw" data from each of the Databases interrogated. Raw data is defined as the data concerning a specific incident which identified the installation, operator, location, date and time. The data so obtained enabled quality checks to be undertaken on the different databases to prevent double counting of an incident or accident.

It is a condition of the contract between the HSE and DNV, the custodians of the WOAD databank, that any information so obtained will only be exported in a non attributable form to protect confidentiality. That is, any request for data obtained by WOAD as a result of this project will result in data being supplied which is non-attributable and will not allow identification of the name of the installation, company, location, date or time of an incident. It will thus be impossible to pinpoint the installation or operator by any means.

1.3 Objectives The main objective of the project is to obtain complete statistics (i.e. accident frequencies) for accidents and incidents having occurred on floating units engaged in the oil and gas activities on the UKCS in the period 1980-2003. Floating units in this project are defined as comprising semi-submersibles, jackups, ships and tension-leg platforms engaged in drilling, accommodation, production and storage. The latter two types are classified as “floating” installations although they are defined as “fixed installations” by the HSE under the Safety Case Regulations.

The results from this study will serve as a reference document for data to be used in future Risk Assessments of offshore floating units and furthermore, be a valuable reference document for UK Health & Safety Executive (HSE)/ Offshore Safety Division (OSD) when reviewing Safety Cases.

To fulfil this objective, relevant databases were interrogated with respect to both population and accident data, thus forming a complete data basis for obtaining comprehensive accident statistics for

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the said type of units, geographical area and time period. The following databases were selected for interrogation: • ORION (the former Sun Safety System), UK HSE-Offshore Safety Division • MAIB accident database, UK Marine Accidents Investigation Bureau • Offshore Blowout Database BLOWOUT, SINTEF, Norway • Worldwide Offshore Accident Databank WOAD, DNV Consulting, Norway It had been noted by the HSE that extensive reference was made to the WOAD database in many of the Safety Cases submitted to them by the offshore operators. Consequently the decision was made to utilise the WOAD incident definitions, codings and format in the new database. Utilising the same methodology and format should enable the operators and owners of offshore installations to readily adapt to the use of the new database. DNV Consulting, as the custodians of the WOAD database was therefore selected as the contractor to undertake the work on behalf of the HSE. A major part of the work of DNV Consulting has thus been the redefining of each incident, in the various databases interrogated, to reflect the definitions, codings and format used in WOAD.

1.4 Results The information being available for each incident has been reviewed and the chain of events has been obtained. The classification of events has been done according to the WOAD concept. One accident may comprise a chain of consecutive events (accident outcomes or occurrences), e.g. a blowout resulting in explosion, fire and oil spill. This means that one single accident or incident may give rise to several occurrences. The total number of occurrences will thus be much higher than the total number of accidents recorded. When giving frequencies per type of event, this is presented as number of occurrences per unit per year. However, when presenting frequencies irrespective of type of event, the figures are given as number of accidents per unit per year.

By combining and merging the results from the interrogation of the four databases, ORION, MAIB, WOAD and BLOWOUT, the accident and occurrence frequencies for floating units in the UKCS in the period 1980-2003 are estimated. In the following tables the accident (or occurrence) frequencies, i.e. number of accidents (or occurrences) per unit year, are given per type of installation, event (only occurrences) and the periods 1980-89, 1990-2003 and 1980-2003. N denotes number of accidents (or occurrences) and F denotes average annual frequency per unit in the specific time period, i.e. number of accidents (or occurrences) per unit and year. The source All databases combined refers to the database obtained by pooling the four mentioned databases and removing the overlapping records. Note that ‘-‘ is applied where no accidents/occurrences have been recorded (and hence no frequencies calculated) or if the given event is not applicable/relevant for the given type of unit.

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The results, after having interrogated the databases and removed overlapping records are also detailed in the associated Excel spreadsheet. The spreadsheet, together with this report, may be downloaded by accessing the HSE web site www.hse.gov.uk . Within the spreadsheet, in addition to other fields each of the incidents is described in “free text”.

Table 1 Mobile drilling units (MODUs). Number of accidents and accident frequencies (per unit-year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of unit N F N F N F

Jackup 198 0.962 660 1.956 858 1.579

Semisub 377 1.102 1386 2.639 1763 2.033

Drillship 5 1.786 35 6.250 40 4.762

Total MODU 580 1.053 2081 2.397 2661 1.875

Table 2 Mobile production units (MOPUs). Number of accidents and accident frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of unit N F N F N F

Jackup - - 26 1.891 26 1.891

Semisub 34 1.889 148 2.309 182 2.217

TLP 29 5.351 78 6.290 107 6.004

Total MOPU 63 2.690 252 2.793 315 2.771

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Table 3 Monohulls (FPSOs and FSUs). Number of accidents and accident frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of unit N F N F N F

FPSO - - 380 3.986 380 3.914

FSU 4 0.505 16 0.486 20 0.490

Total Monohull 4 0.414 396 3.088 400 2.900

Table 4 All floating units (excl. accommodation units). Number of accidents and accident frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of unit N F N F N F

MODU 580 1.053 2081 2.397 2661 1.875

MOPU 63 2.690 252 2.793 315 2.771

Monohull 4 0.414 396 3.088 400 2.900

Total floating units 647 1.108 2729 2.511 3376 2.021

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Table 5 All floating units (excl accommodation units). Number of occurrences and occurrence frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of event N F N F N F

Anchor failure 58 0.099 160 0.147 218 0.131

Blowout 2 3.4•10-3 17 0.016 19 0.011

Capsize 2 3.4•10-3 1 9.2•10-4 3 1.8•10-3

Collision 4 6.9•10-3 15 0.014 19 0.011

Contact 64 0.110 140 0.129 204 0.122

Crane 282 0.483 1077 0.991 1359 0.813

Explosion 13 0.022 14 0.013 27 0.016

Falling object 290 0.497 1319 1.214 1609 0.963

Fire 48 0.082 189 0.174 237 0.142

Foundering 1 1.7•10-3 1 9.2•10-4 2 1.2•10-3

Grounding 3 5.1•10-3 1 9.2•10-4 4 2.4•10-3

Helicopter 4 6.9•10-3 5 4.6•10-3 9 5.4•10-3

Leakage 6 0.010 18 0.017 24 0.014

List 3 5.1•10-3 12 0.011 15 9.0•10-3

Machinery - - 4 3.7•10-3 4 2.4•10-3

Off position 16 0.027 24 0.022 40 0.024

Spill/release 58 0.099 567 0.522 625 0.374

Structural 33 0.057 39 0.036 72 0.043

Towing/towline 14 0.024 14 0.013 28 0.017

Well problem 32 0.055 243 0.224 275 0.165

Other 10 0.017 64 0.059 74 0.044

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2 INTRODUCTION In 1999, during a project undertaken by DNV on behalf of the UK Health & Safety Executive (HSE), four databases holding information about UK Continental Shelf (UKCS) semi-submersible flooding incidents were interrogated. The survey revealed that that none of them had a complete recording of such incidents. In addition, it was identified that there were incidents which were not recorded in any of these sources. Consequently, the event frequencies being obtained varied with the availability of sources. There was no reason to believe that the situation and figures for other types of events on floating units should be any different. Hence, it was proposed to initiate a series of projects, but addressing all types of risks to floating units. The most recent one, completed in 2003, shows statistics covering the period 1980-2001 (ref. /1/). This current project updates the data of the previous projects by two further years, 2002 and 2003.

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3 OBJECTIVES AND SCOPE OF WORK The main objective of the project is to obtain complete statistics, i.e. accident frequencies, for accidents and incidents having occurred on floating units engaged in the oil and gas activities on the UK Continental Shelf in the period 1980-2003. Floating units in this project are defined to comprise drilling, accommodation, and floating production and storage units. The classification of units is according to the following:

Category Type of unit

Mobile drilling unit (MODU) Jackup, Semisubmersible

Mobile production unit (MOPU) Jackup, Semisubmersible, Tension-leg platform (TLP)

Monohull Floating storage unit (FSU), Floating production, storage and offloading unit (FPSO)

Accommodation unit Jackup, Semisubmersible

It should be noted that in this project FPSO’s, FSU’s, and TLP’s are classified as “floating installations” although they are classified as “fixed installations” by the HSE under the Safety Case Regulations.

The results from this study will serve as a reference document for data to be used in future Risk Assessments of offshore floating units and furthermore, be a valuable reference document for HSE/OSD when reviewing Safety Cases.

To fulfil this objective, relevant databases were interrogated with respect to both population and accident data, thus forming a complete data basis for obtaining comprehensive accident statistics for the said type of units, geographical area and time period. The following databases were selected for interrogation: • ORION*, UK HSE-Offshore Safety Division • MAIB accident database, UK Marine Accidents Investigation Bureau • Offshore Blowout Database BLOWOUT, SINTEF, Norway • Worldwide Offshore Accident Databank WOAD, Det Norske Veritas (DNV), Norway *): The former “Sun Safety System”

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4 EXPOSURE DATA Exposure (population) data in this context relates to the number of unit- (or rig-) years for each type of platform or installation. By interrogating relevant sources holding such information, the number of unit-years are obtained for each year and type of unit for the UKCS in the period 1980-2003. The results are shown in several tables in the following sub-chapters. The classification of units is shown in the previous chapter. Note that ‘-‘ is applied to indicate that no units are in service in the specific year/period.

4.1 Mobile offshore drilling units (MODUs) From WOAD, the exposure data for MODUs on the UKCS are obtained. The data are given in Table 6 below.

Table 6 MODUs. UKCS, 1980-2003. Number of unit years Type of MODU

Year Jackup Semisub Drillship Total

1980-89 205.9 342.1 2.8 550.8

1990 27.8 46.1 0.4 74.3

1991 29.7 49.3 0.4 79.4

1992 29.0 48.2 0.4 77.6

1993 26.6 44.2 0.4 71.2

1994 21.7 36.0 0.3 58.0

1995 20.7 34.4 0.3 55.4

1996 23.0 38.2 0.3 61.5

1997 21.7 36.1 0.3 58.1

1998 22.0 36.5 0.3 58.8

1999 24.0 32.3 1.0 57.3

2000 22.4 30.2 0.3 52.9

2001 23.1 30.4 0.4 53.9

2002 22.7 32.6 0.7 56.0

2003 23.1 30.7 0.1 53.9

1990-2003 337.5 525.2 5.6 868.3

1980-2003 543.4 867.3 8.4 1419.1

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4.2 Mobile Production Units (MOPUs) These units comprise conversions and purpose-built producing jackups, semi-submersibles, and tension-leg platforms (TLPs). From ref. /2/ the number of unit years are calculated. Table 7 summarises the results of this exercise.

Table 7 MOPUs. UKCS, 1980-2003. Number of unit years Name of unit Type of unit Date of first oil

production (mm-yy)

Date of abandonment

(mm-yy)

Number of unit-years 1980-2003

AH001 Semi-sub 07-89 14.5

Balmoral 16/21 Semi-sub 11-86 17.2

Buchan ‘A’ Semi-sub 05-81 22.7

Elgin TPG 5000 Jackup 01-98 6.0

Harding Jackup 04-96 7.8

Hutton TLP TLP 08-84 05-2002 17.8

Janice ‘A’ 2 Semi-sub 02-99 4.9

North Sea Pioneer Semi-sub 04-89 01-91 1.8

Northern Producer1 Semi-sub 08-92 11.4

Sedco 707 Semi-sub 05-94 02-99 4.8

Transworld 58 Semi-sub 06-75 12-84 4.9

Total - - - 113.7

1): ex Emerald Producer; 2): ex West Royal

The exposure data are further broken down and distributed on year and type of unit. The table below summarises the results.

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Table 8 MOPUs. UKCS, 1980-2003. Number of unit years per year and type of unit

Type of unit

Year Semi-sub Jackup TLP Total

1980-89 18.0 - 5.4 23.4

1990 4.0 - 1.0 5.0

1991 3.0 - 1.0 4.0

1992 3.4 - 1.0 4.4

1993 4.0 - 1.0 5.0

1994 4.7 - 1.0 5.7

1995 5.0 - 1.0 6.0

1996 5.0 0.8 1.0 6.8

1997 5.0 1.0 1.0 7.0

1998 5.0 2.0 1.0 8.0

1999 5.0 2.0 1.0 8.0

2000 5.0 2.0 1.0 8.0

2001 5.0 2.0 1.0 8.0

2002 5.0 2.0 0.4 7.4

2003 5.0 2.0 - 7.0

1990-2003 64.1 13.8 12.4 90.3

1980-2003 82.1 13.8 17.8 113.7

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4.3 Monohull units These units comprise Floating Storage Units (FSUs) and Floating Production, Storage and Offloading units (FPSOs). Based on information from HSE-OSD’s database on UKCS monohulls, the number of unit years are calculated. Table 9 summarises the results from querying that database.

Table 9 Monohulls. UKCS, 1980-2003. Number of unit years Name of unit Type of unit Constr.

(P/C)*Date of first oil

production (mm-yy)

Date of abandonment

(mm-yy)

No. of unit-years 1980-2003

Ailsa Craig FSU C 08-92 02-96 3.5

Alba FSU FSU P 01-94 10.0

Anasuria FPSO P 10-96 7.3

Bleo Holm FPSO P 04-99 4.8

Captain FPSO FPSO P 06-97 6.6

Curlew FPSO FPSO C 11-97 6.2

Fulmar FSU FSU C 02-82 06-94 12.3

Glas Dowr FPSO P 08-97 06-99 1.9

Global Producer III FPSO P 01-2001 3.0

Gryphon ‘A’ FSPO P 01-93 11.0

Haewene Brimm** FPSO P 02-99 4.9

Liverpool Bay Osi FSU P 03-96 7.8

Nordic Apollo FSU C 12-2000 3.1

North Sea Producer FPSO C 08-97 6.4

Petrojarl 1 FPSO P 03-95 04-2001 6.1

Petrojarl Foinaven FPSO P 11-97 6.2

Ramform Banff FPSO P 02-99 4.9

Schiehallion FPSO FPSO P 07-98 5.5

Seillean FPSO P 04-88 11-97 9.6

Triton FPSO P 08-99 4.4

Uisge Gorm FPSO C 08-95 8.4

Vinga FSU P 09-93 10-97 4.1

Total 138.1

*) C: Converted tankers, P: Purpose-built **) Ex. Berge Hugin

The exposure data are further broken down and distributed on year and type of unit. The two following tables summarise the results.

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Table 10 Monohulls. UKCS, 1980-2003. Number of unit years per type of unit Type of unit

Year FPSO FSU Total

1980-89 1.8 7.9 9.7

1990 1.0 1.0 2.0

1991 1.0 1.0 2.0

1992 1.0 1.4 2.4

1993 2.0 2.3 4.3

1994 2.0 3.4 5.4

1995 3.3 3.0 6.3

1996 4.3 2.9 7.2

1997 6.6 2.8 9.3

1998 9.5 2.0 11.5

1999 12.5 2.0 14.5

2000 13.0 2.1 15.1

2001 13.3 3.0 16.3

2002 13.0 3.0 16.0

2003 13.0 3.0 16.0

1990-2003 95.5 32.9 128.4

1980-2003 97.3 40.8 138.1

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Table 11 Monohulls. UKCS, 1980-2003. Number of unit years per type of unit and construction

Type of unit and construction

FPSO FSU

Year Purpose-built Converted Purpose-built Converted

1980-89 1.8 - - 7.9

1990 1.0 - - 1.0

1991 1.0 - - 1.0

1992 1.0 - - 1.4

1993 2.0 - 0.3 2.0

1994 2.0 - 2.0 1.4

1995 2.9 0.4 2.0 1.0

1996 3.3 1.0 2.8 0.1

1997 5.0 1.6 2.8 -

1998 6.5 3.0 2.0 -

1999 9.5 3.0 2.0 -

2000 10.0 3.0 2.0 0.1

2001 10.3 3.0 2.0 1.0

2002 10.0 3.0 2.0 1.0

2003 10.0 3.0 2.0 1.0

1990-2003 74.5 21.0 21.9 11.0

1980-2003 76.3 21.0 21.9 18.9

4.4 Accommodation Units Several potential sources for such information were consulted with no success. It was concluded that if such data was to be obtained, extensive manual work had to be performed. Hence no exposure data for accommodation units was obtained within the scope of this study. This implies that no accident and incident frequencies for these units are calculated in this report.

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5 INCIDENT REPORTING IN UK WATERS The existing reporting requirements of incidents on floating units operating (working, in transit or docked) on the UKCS depend on geographical location and operation mode at the time of the incident. The receiver of information is either the Health and Safety Executive - Offshore Safety Division (HSE-OSD), the Health and Safety Executive – Field Operations Division (HSE-FOD) or the Marine Accident Investigation Branch (MAIB).

In the following three chapters one may find some documentation of the incident and accident reporting regime for offshore vessels in UK waters. This regime may be summarised as shown in the table below.

Table 12 Overview of the UKCS incident reporting regime; UK and non-UK flagged vessels

Location/activity Flag Report to

UK MAIB Within the 12-mile limit and not an Offshore Installation (e.g. in transit) Non UK* MAIB

UK MAIB Outside the 12-mile limit and not an Offshore Installation (e.g. in transit) Non UK* Flag state

UK HSE-OSD Working as an Offshore Installation (e.g. drilling, production, accommodation) Non UK* HSE-OSD

UK HSE-FOD Alongside at a shipyard (e.g. for repair or maintenance) Non UK* HSE-FOD

*): Presumably the non-UK flagged vessels would also report to the relevant Flag State

Descriptions of the three main databases holding this information and operated by the HSE and MAIB, are also given.

Further details regarding the reporting regime and the databases may be found in ref. /1/.

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6 OVERVIEW OF DATABASES This chapter gives a short presentation of the 4 databases being interrogated in this project.

6.1 ORION The Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995 (RIDDOR 95) arrangement came into force on 1 April 1996 and requires that all work-related accidents, diseases and dangerous occurrences in the UK and UK Continental Shelf are to be reported to the HSE. It applies to all work activities and to defined types of incidents. The incidents are to be reported using the OIR/9B and F2508A forms. These forms are to be completed and submitted to the HSE.

Prior to 1 April 1996 injuries and dangerous occurrences were reported on the OIR/9A form. This form was created under the Mineral Workings (Offshore Installations) Act 1971 and the Offshore Installations (Inspectors and Casualties) Regulations 1973.

The information submitted on the OIR/9A, OIR/9B and F2508A forms are recorded in a database, “ORION” (the former Sun Safety System), run by the HSE-OSD offices in Bootle, Liverpool.

The Sun Safety System (now ORION) was primarily developed to record incident data reported on the OIR/9A form. Other information is however recorded on the database, including details of inspections, investigations, prosecutions and the registration and location details of Offshore Installations. The OIR/9A form was first published in October 1990, and the Sun Safety System was implemented in 1st January 1991. The Sun Safety System does however contain some data on pre 1991 incidents (imported from previous systems maintained by the Safety Directorate of the Department of Energy), though not all fields on the OIR/9A form are available for this data. The Sun Safety System was decommissioned year 2000 and all data from 1991(incl.) was transferred to ORION.

Note that notification of hydrocarbon releases (voluntarily submitted on the OIR/12 form) are also recorded in a separate and specifically designed database which is maintained by the HSE-OSD offices in Bootle, Liverpool.

6.2 MAIB The Marine Accident Investigation Branch (MAIB) is a distinct and separate branch within the Department of the Environment, Transport and the Regions (DETR). Its Chief Inspector reports directly to the Secretary of State for the Environment, Transport and the Regions on marine accident investigations. The authority of the MAIB to investigate marine accidents originates from the Merchant Shipping Act 1995. MAIB’s responsibility covers the investigation of accidents to or on:

all UK registered vessels anywhere in the world other vessels being within the 12-mile zone of the UK coast (UK territorial waters)

For offshore floating vessels all accidents and incidents occurring in transit should be reported to MAIB according to the above.

Accidents must be reported as soon as possible to the MAIB by the quickest means available. Serious injuries and dangerous occurrences must be reported within 14 days or within 14 days after

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arrival at the next port if the vessel is at sea at time of the accident. The reporting form presently being used is IRF (1/98).

About 2000 accidents are reported per year to MAIB of which about 500 require some sort of MAIB correspondence follow-up, for clarification purposes or investigation. Most of these are from UK waters. Additional information about reporting and investigations of accidents by the MAIB is found in Memorandum on the Investigations of Marine Accidents; MAIB/DETR. January 1998.

MAIB maintains a database covering accidents and incidents from 1991 to date. The received forms and notifications are recorded in the database by a staff of two persons. Beside the said forms and notifications, the ‘Coast Guard Morning Reports’ serves as first-hand information input to the database. Today the database contains some 18.000 events covering all types of incidents and accidents, ranging from smaller low-consequence events and near-misses to major accidents with loss of life.

6.3 BLOWOUT The SINTEF Offshore Blowout Database (BLOWOUT) is a comprehensive event database for blowout risk assessment. The database includes information on 515 (November 2004) offshore blowouts/well releases that have occurred worldwide since 1955. The database includes blowout/well release descriptions worldwide and drilling and production exposure data for several areas with focus on the US Gulf of Mexico Outer Continental Shelf (US GoM OCS), Norwegian waters, and UK waters.

The blowouts/well releases are categorized in several parameters, emphasizing blowout causes. The database contains 51 different fields describing each blowout/well release. In addition, the database allows for attachment of any electronic file(s) to the blowout description. The various fields are grouped in six different groups:

• Category and location

• Well description

• Present operation

• Blowout causes

• Blowout Characteristics

• Other

ExproSoft has been contracted to operate the SINTEF Offshore Blowout Database from 1 May 2001 by SINTEF.

6.4 WOAD One of the main sources for offshore accident information for public use is the Worldwide Offshore Accident Databank (WOAD) operated by Det Norske Veritas (DNV). WOAD contains some 5,000 events from the period 1970-2004, derived mainly from public-domain sources such as Lloyds Casualty Reports, newspapers and official publications. Most of the data is from the UK and Norwegian Sectors and the US Gulf of Mexico. Exposure data is also provided, allowing accident rates to be calculated for different accident types, unit types, geographical locations, degrees of damage, etc.

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7 EVENT CLASSIFICATION AND CODING PRINCIPLES The WOAD concept of classifying events has been selected for the review work on the records received from the databases being interrogated in this project. Hence all events have been categorised according to the table below.

Table 13 Event classification, WOAD

Type of event Explanation

Anchor failure Problems with anchor/anchor lines, mooring devices, winching equipment or fairleads (e.g. anchor dragging, breaking of mooring lines, loss of anchor(s), winch failures).

Blowout An uncontrolled flow of gas, oil or other fluids from the reservoir, i.e. loss of 1. barrier (i.e. hydrostatic head) or leak and loss of 2. barrier, i.e. BOP/DHSV.

Capsize Loss of stability resulting in overturn of unit, capsizing, or toppling of unit.

Collision Accidental contact between offshore unit and/or passing marine vessel when at least one of them is propelled or is under tow. Examples: tanker, cargo ship, fishing vessel. Also included are collisions with bridges, quays, etc., and vessels engaged in the oil and gas activity on other platforms than the platform affected, and between two offshore installations (to be coded as CN only when intended for close location).

Contact Collisions/accidental contacts between vessels engaged in the oil and gas activity on the platform affected, e.g. support/supply/stand-by vessels, tugs or helicopters, and offshore installations (floating or fixed). Also are included collisions between two offshore installations only when these are intended for close location.

Crane Any event caused by or involving cranes, derrick and draw-works, or any other lifting equipment.

Explosion Explosion

Falling object Falling load/dropped objects from crane, drill derrick, or any other lifting equipment or platform. Crane fall and lifeboats accidentally to sea and man overboard are also included.

Fire Fire.

Foundering Loss of buoyancy or unit sinking.

Grounding Floating installation in contact with the sea bottom.

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Type of event Explanation

Helicopter Accident with helicopter either on helideck or in contact with the installation.

Leakage Leakage of water into the unit or filling of shaft or other compartments causing potential loss of buoyancy or stability problems.

List Uncontrolled inclination of unit.

Machinery failure Propulsion or thruster machinery failure (incl. control)

Off position Unit unintentionally out of its expected position or drifting out of control.

Spill/release “Loss of containment”. Release of fluid or gas to the surroundings from unit's own equipment/vessels/tanks causing (potential) pollution and/or risk of explosion and/or fire.

Structural Breakage or fatigue failures (mostly failures caused by weather, but not necessarily) of structural support and direct structural failures. "Punch through" also included.

Towing/towline Towline failure or breakage

Well problem Accidental problem with the well, i.e. loss of one barrier (hydrostatic head) or other downhole problems.

Other Event other than specified above

The categorisation of the incidents has been performed according to principles outlined below. • Events coded as Falling load involve loads and objects rolling, leaning, tilting, falling, rotating,

swinging, or sliding. Man over board is also included here. • “Occupational Hazard” (OH) incidents, with personal injuries or not, are defined to be events

which are not related to operations of equipment and events caused by obvious human errors during maintenance. Such events have only been counted, but are excluded from the statistics (i.e. no frequencies).

• Anchor handling involving supply boat which causes personal injuries to personnel being involved are coded as Anchor failure (and not OH).

• Maloperation of lifting equipment or technical failure leading to falling load is coded as Crane failure + Falling load.

• Problems with riser tensioners are coded as Crane failure • Events involving equipment or part of equipment bursting or blowing out, are coded as

Spill/Release • Events involving problems with gangways/bridges between floating unit and other floating or

fixed units, are coded as Out of position + Falling load. • Incidents that occur during maintenance indicates lack of design have been coded accordingly

(crane failure, falling load, anchor failure, etc.)

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8 ACCIDENT STATISTICS The information being available for each incident has been reviewed and the chain of events has been obtained. The classification of events has been done according to the WOAD concept. One accident may comprise a chain of consecutive events (accident outcomes or occurrences), e.g. a blowout resulting in explosion, fire and oil spill. This means that one single accident or incident may give rise to several occurrences. The total number of occurrences will thus be much higher than the total number of accidents recorded. When giving frequencies per type of event, this is presented as number of occurrences per unit per year. However, when presenting frequencies irrespective of type of event, the figures are given as number of accidents per unit per year.

By combining and merging the results from the interrogation of all 4 databases, the accident/occurrence frequencies for floating units in the UKCS in the period 1980-2003 are estimated. All tables in this chapter present the number of accidents and occurrences with corresponding frequencies per type of unit (MODU, MOPU, Monohull), event (only occurrences) and time periods 1980-89, 1990-2003 and 1980-2003. N denotes number of occurrences and F denotes average annual frequency, i.e. number of accidents or occurrences per unit and year. Note that ‘-‘ is applied where no accidents/occurrences have been recorded (and hence no frequencies calculated) or if the given event is not applicable/relevant for the given type of unit.

The source All databases combined refers to the database obtained by pooling the databases ORION, MAIB, BLOWOUT and WOAD and removing the overlapping records.

Note: More detailed statistics are given in appendix A where the number of accidents/occurrences and corresponding frequencies is given by type of unit and year in the period 1990-2003

The results, after having interrogated the databases and removed overlapping records are also detailed in the associated Excel spreadsheet. The spreadsheet, together with this report, may be downloaded by accessing the HSE web site www.hse.gov.uk . Within the spreadsheet, in addition to other fields each of the incidents is described in “free text”.

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8.1 Accident frequencies, all databases combined In this section the accident frequencies for floating units in the UKCS in the period 1980-2003 are presented. The following tables give the number of accidents and corresponding frequencies per type of unit.

Table 14 Mobile drilling units (MODUs). Number of accidents and accident frequencies (per unit-year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of unit N F N F N F

Jackup 198 0.962 660 1.956 858 1.579

Semisub 377 1.102 1386 2.639 1763 2.033

Drillship 5 1.786 35 6.250 40 4.762

Total MODUs 580 1.053 2081 2.397 2661 1.875

Table 15 Mobile production units (MOPUs). Number of accidents and accident frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of unit N F N F N F

Jackup - - 26 1.891 26 1.891

Semisub 34 1.889 148 2.309 182 2.217

TLP 29 5.351 78 6.290 107 6.004

Total MOPUs 63 2.690 252 2.793 315 2.771

Table 16 Monohulls (FPSOs and FSUs). Number of accidents and accident frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of unit N F N F N F

FPSO - - 380 3.986 380 3.914

FSU 4 0.505 16 0.486 20 0.490

Total Monohulls 4 0.414 396 3.088 400 2.900

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Table 17 All floating units (excl. accommodation units). Number of accidents and accident frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of floating unit N F N F N F

MODU 580 1.053 2081 2.397 2661 1.875

MOPU 63 2.690 252 2.793 315 2.771

Monohull 4 0.414 396 3.088 400 2.900

All floating 647 1.108 2729 2.511 3376 2.021

8.2 Number of accidents for accommodation units Since no exposure data for these types of units are readily available, only the number of accidents are given (i.e. no frequencies). These units comprise both the jackup and semisubmersible types.

Table 18 Accommodation units. Number of accidents . UKCS, 1980-2003. Source: All databases combined

Period

Type of unit 1980-1989 1990-2003 1980-2003

Jackup 6 10 16

Semi-submersible 23 71 94

Total accommodation units 29 81 110

8.3 Occurrence frequencies, all databases combined In this section the occurrence frequencies for floating units in the UKCS in the period 1980-2003 are presented. The following tables give the number of occurrences and corresponding frequencies per type of occurrence/event and type of unit.

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Table 19 All floating units. UKCS, 1980-2003. No. of occurrences. Source: All databases combined Number of occurrences

Type of event

Mobile Drilling Units

Mobile Production

Units

Monohull Units

AccommodationUnits

Total

Anchor failure 198 8 12 26 244

Blowout 18 1 - - 19

Capsize 3 - - - 3

Collision 19 - - 1 20

Contact 183 7 14 10 214

Crane 1200 102 57 30 1389

Explosion 21 4 2 1 28

Falling object 1422 116 71 46 1655

Fire 161 35 41 10 247

Foundering 2 - - - 2

Grounding 4 1 5

Helicopter 7 1 1 3 12

Leakage 23 - 1 1 25

List 14 - 1 1 16

Machinery 3 - 1 1 5

Off position 37 1 2 11 51

Spill/release 260 125 240 1 626

Structural 61 4 7 7 79

Towing/towline 28 - - 1 29

Well problem 266 7 2 - 275

Other 42 7 25 2 76

The following tables give the number of occurrences and corresponding frequencies per type of unit (MODU, MOPU, Monohull) and year/period.

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Table 20 Mobile drilling units (MODUs). Number of occurrences and occurrence frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of event N F N F N F

Anchor failure 54 0.098 144 0.166 198 0.140

Blowout 2 3.6•10-3 16 0.018 18 0.013

Capsize 2 3.6•10-3 1 1.2•10-3 3 2.1•10-3

Collision 4 7.3•10-3 15 0.017 19 0.013

Contact 61 0.111 122 0.141 183 0.129

Crane 251 0.456 949 1.093 1200 0.846

Explosion 11 0.020 10 0.012 21 0.015

Falling object 262 0.476 1160 1.336 1422 1.002

Fire 38 0.069 123 0.142 161 0.114

Foundering 1 1.8•10-3 1 1.2•10-3 2 1.4•10-3

Grounding 3 5.4•10-3 1 1.2•10-3 4 2.8•10-3

Helicopter 4 7.3•10-3 3 3.5•10-3 7 4.9•10-3

Leakage 6 0.011 17 0.020 23 0.016

List 3 5.4•10-3 11 0.013 14 9.9•10-3

Machinery - - 3 3.5•10-3 3 2.1•10-3

Off position 14 0.025 23 0.027 37 0.026

Spill/release 48 0.087 212 0.244 260 0.183

Structural 28 0.051 33 0.038 61 0.043

Towing/towline 14 0.025 14 0.016 28 0.020

Well problem 32 0.059 234 0.270 266 0.187

Other 8 0.015 34 0.039 42 0.030

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Table 21 Mobile production units (MOPUs). Number of occurrences and occurrence frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of event N F N F N F

Anchor failure 4 0.171 4 0.044 8 0.082

Blowout - - 1 0.011 1 0.010

Capsize - - - - - -

Collision - - - - - -

Contact 3 0.128 4 0.044 7 0.072

Crane 29 1.238 73 0.809 102 1.051

Explosion 2 0.085 2 0.022 4 0.041

Falling object 26 1.110 90 0.997 116 1.194

Fire 9 0.384 26 0.288 35 0.361

Foundering - - - - - -

Grounding - - - - - -

Helicopter - - 1 0.011 1 0.010

Leakage - - - - - -

List - - - - - -

Machinery - - - - - -

Off position 1 0.043 - - 1 0.010

Spill/release 9 0.384 116 1.286 125 1.288

Structural 4 0.171 - - 4 0.041

Towing/towline - - - - - -

Well problem - - 7 0.078 7 0.072

Other 2 0.085 5 0.055 7 0.072

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TECHNICAL REPORT

Table 22 Monohulls (FPSOs and FSUs). Number of occurrences and occurrence frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of event N F N F N F

Anchor failure - - 12 0.094 12 0.087

Blowout - - - - - -

Capsize - - - - - -

Collision - - - - - -

Contact - - 14 0.109 14 0.102

Crane 2 0.207 55 0.429 57 0.413

Explosion - - 2 0.016 2 0.015

Falling object 2 0.207 69 0.538 71 0.515

Fire 1 0.103 40 0.312 41 0.297

Foundering - - - - - -

Grounding - - - - - -

Helicopter - - 1 7.8•10-3 1 7.3•10-3

Leakage - - 1 7.8•10-3 1 7.3•10-3

List - - 1 7.8•10-3 1 7.3•10-3

Machinery - - 1 7.8•10-3 1 7.3•10-3

Off position 1 0.103 1 7.8•10-3 2 0.015

Spill/release 1 0.103 239 1.864 240 1.740

Structural 1 0.103 6 0.047 7 0.051

Towing/towline - - - - - -

Well problem - - 2 0.016 2 0.015

Other - - 25 0.195 25 0.181

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TECHNICAL REPORT

Table 23 All floating units (excl accommodation units). Number of occurrences and occurrence frequencies (per unit year). UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of event N F N F N F

Anchor failure 58 0.099 160 0.147 218 0.131

Blowout 2 3.4•10-3 17 0.016 19 0.011

Capsize 2 3.4•10-3 1 9.2•10-4 3 1.8•10-3

Collision 4 6.9•10-3 15 0.014 19 0.011

Contact 64 0.110 140 0.129 204 0.122

Crane 282 0.483 1077 0.991 1359 0.813

Explosion 13 0.022 14 0.013 27 0.016

Falling object 290 0.497 1319 1.214 1609 0.963

Fire 48 0.082 189 0.174 237 0.142

Foundering 1 1.7•10-3 1 9.2•10-4 2 1.2•10-3

Grounding 3 5.1•10-3 1 9.2•10-4 4 2.4•10-3

Helicopter 4 6.9•10-3 5 4.6•10-3 9 5.4•10-3

Leakage 6 0.010 18 0.017 24 0.014

List 3 5.1•10-3 12 0.011 15 9.0•10-3

Machinery - - 4 3.7•10-3 4 2.4•10-3

Off position 16 0.027 24 0.022 40 0.024

Spill/release 58 0.099 567 0.522 625 0.374

Structural 33 0.057 39 0.036 72 0.043

Towing/towline 14 0.024 14 0.013 28 0.017

Well problem 32 0.055 243 0.224 275 0.165

Other 10 0.017 64 0.059 74 0.044

8.4 Number of occurrences for accommodation units Since no exposure data for these type of units are available, only the number of occurrences are given (i.e. no frequencies). These units comprise both the jackup and semisubmersible types.

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TECHNICAL REPORT

Table 24 Accommodation units. Number of occurrences. UKCS, 1980-2003. Source: All databases combined

Period

1980-1989 1990-2003 1980-2003

Type of event Jackup Semi-submersible

Jackup Semi-submersible

Jackup Semi-submersible

Anchor failure - 3 2 21 2 24

Blowout - - - - - -

Capsize - - - - - -

Collision - - - 1 - 1

Contact 2 3 2 3 4 6

Crane 2 6 4 18 6 24

Explosion - 1 - - - 1

Falling object 3 11 5 27 8 38

Fire - 1 - 9 - 10

Foundering - - - - - -

Grounding - - - 1 - 1

Helicopter - 2 - 1 - 3

Leakage - - - 1 - 1

List - - - 1 - 1

Machinery - - - 1 - 1

Off position - 2 - 9 - 11

Spill/release - - 1 - 1 -

Structural 1 1 1 4 2 5

Towing/towline - - - 1 - 1

Well problem - - - - - -

Other - 1 - 1 - 2

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TECHNICAL REPORT

9 CONCLUSIONS The conclusions from the work undertaken in this project are summarised below. • The main source for accident and incident information available to the UKCS offshore industry

should be this database as it, and the associated spreadsheet, contain comprehensive UKCS data from the most relevant accident databases

This database is understood to be the only UKCS accident and incident database which is both publically and freely available to the offshore industry and others. It has been created in the WOAD format, with which the offshore industry is familiar and it is regularly updated with accident and incident information from relevant international databases. In addition the format of the spreadsheet, which contains a free text description of each incident allows a sort capability to be utilised thus enabling specific data to be extracted from the database as and when required.

• Large difference in number of accidents between WOAD and ORION When comparing the information held by DNV’s Worldwide Offshore Accident Databank (WOAD) and ORION, there is a big difference in number of accidents. This is mainly explained by the fact that WOAD receives information about accidents through publicly available sources, which in most cases only addresses events with large consequences. However, if considering the Norwegian Continental Shelf (NCS), WOAD contains information about accidents and incidents on the same level as ORION on the UKCS, due to an arrangement between the Norwegian Petroleum Safety Agency and DNV for transferring information to WOAD.

• Increase in event frequencies when merging all databases together If all floating units are considered for the period 1980-2003, this study demonstrates a total accident frequency of 2.02 per installation per year. This compares to an accident frequency of 0.1 from WOAD alone, a factor of some 20 times lower. However, it should be noted that if only frequencies for accidents of the “highest severity” are compared then the increase in accident frequency is about 3 times. The factor of 20 only applies when considering accidents and incidents of all severities.

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TECHNICAL REPORT

10 REFERENCES

/1/

Accident statistics for floating offshore units on the UK Continental Shelf 1980 – 2001. Det Norske Veritas/UK Health & Safety Executive. Research Report Series. Report No. RR095. http://www.hse.gov.uk/research/rrhtm/rr095.htm

/2/

Mobile Production Systems of the World. Access Database. CD-ROM, Oilfield Publishing Limited (OPL), November 2003

- o0o -

Page 30 .

TECHNICAL REPORT

Page A-1

APPENDIX A

DETAILED STATISTICS

TECHNICAL REPORT

Page A-2

A. 1 Introduction The information being available for each incident has been reviewed and the chain of events has been obtained. The classification of events has been done according to the WOAD concept. One accident may comprise a chain of consecutive events (accident outcomes or occurrences), e.g. a blowout resulting in explosion, fire and oil spill. This means that one single accident or incident may give rise to several occurrences. The total number of occurrences will thus be much higher than the total number of accidents recorded. When giving frequencies per type of event, this is presented as number of occurrences per unit per year.

A. 2 Accident statistics By combining and merging the results from the interrogation of all 4 databases, the occurrence frequencies for floating units in the UKCS in the period 1980-2003 are estimated. All tables in this appendix present the number of occurrences with corresponding frequencies per type of unit and event for the time periods 1980-89, 1990-2003 and 1980-2003 and for each year in the period 1990-2003. N denotes number of occurrences and F denotes average annual frequency per unit, i.e. number of occurrences per unit year. Since no exposure data are readily available for floating accommodation units (comprising both the jackup and semisubmersible types), only the number of occurrences are given (i.e. no frequencies). Note that ‘-‘ is applied where no accidents/occurrences have been recorded (and hence no frequencies calculated) or if the given event is not applicable/relevant for the given type of unit.

The source All databases combined refers to the database obtained by pooling the databases ORION, MAIB, BLOWOUT and WOAD and removing the overlapping records.

The results, after having interrogated the databases and removed overlapping records are also detailed in the associated Excel spreadsheet. The spreadsheet, together with this report, may be downloaded by accessing the HSE web site www.hse.gov.uk . Within the spreadsheet, in addition to other fields each of the incidents is described in “free text”.

TECHNICAL REPORT

Page A-3

An index of sections and tables in this appendix is shown on the two next pages in order to ease retrieval of relevant data.

Section and table number Page no. A.2.1 Occurrence frequencies - Mobile Drilling Units (MODUs) Table 25 Drilling jackups. UKCS, 1980-89, 1990-92 A- 5 Table 26 Drilling jackups. UKCS, 1993-1996 A- 6 Table 27 Drilling jackups. UKCS, 1997-1999 A- 7 Table 28 Drilling jackups. UKCS, 2000-2003 A- 8 Table 29 Drilling jackups. UKCS, 1990-2003, 1980-2003 A- 9 Table 30 Drilling semisubmersibles. UKCS, 1980-89, 1990-92 A- 10 Table 31 Drilling semisubmersibles. UKCS, 1993-1996 A- 11 Table 32 Drilling semisubmersibles. UKCS, 1997-1999 A- 12 Table 33 Drilling semisubmersibles. UKCS, 2000-2003 A- 13 Table 34 Drilling semisubmersibles. UKCS, 1990-2003, 1980-2003 A- 14 Table 35 Drillships. UKCS, 1980-89, 1990-92 A- 15 Table 36 Drillships. UKCS, 1993-1996 A- 16 Table 37 Drillships. UKCS, 1997-1999 A- 17 Table 38 Drillships. UKCS, 2000-2003 A- 18 Table 39 Drillships. UKCS, 1990-2003, 1980-2003 A- 19 A.2.2 Occurrence frequencies - Mobile Production Units (MOPUs) Table 40 Production jackups. UKCS, 1980-2003 A- 20 Table 41 Production semisubmersibles. UKCS, 1980-89, 1990-92 A- 21 Table 42 Production semisubmersibles. UKCS, 1993-1996 A- 22 Table 43 Production semisubmersibles. UKCS, 1997-1999 A- 23 Table 44 Production semisubmersibles. UKCS, 2000-2003 A- 24 Table 45 Production semisubmersibles. UKCS, 1990-2003, 1980-2003 A- 25 Table 46 Tension-leg platforms. UKCS, 1980-89, 1990-92 A- 26 Table 47 Tension-leg platforms. UKCS, 1993-1996 A- 27 Table 48 Tension-leg platforms. UKCS, 1997-1999 A- 28 Table 49 Tension-leg platforms. UKCS, 2000-2003 A- 29 Table 50 Tension-leg platforms. UKCS, 1990-2003, 1980-2003 A- 30 (continued…)

TECHNICAL REPORT

Page A-4

Section and table number Page no. A.2.3 Occurrence frequencies – Monohull units Table 51 FPSOs. UKCS, 1980-89, 1990-92 A- 32 Table 52 FPSOs. UKCS, 1993-1996 A- 33 Table 53 FPSOs. UKCS, 1997-1999 A- 34 Table 54 FPSOs. UKCS, 2000-2003 A- 35 Table 55 FPSOs. UKCS, 1990-2003, 1980-2003 A- 36 Table 56 FPSOs. UKCS, 1980-2003 A- 37 Table 57 FSUs. UKCS, 1980-89, 1990-92 A- 38 Table 58 FSUs. UKCS, 1993-1996 A- 39 Table 59 FSUs. UKCS, 1997-1999 A- 40 Table 60 FSUs. UKCS, 2000-2003 A- 41 Table 61 FSUs. UKCS, 1990-2003, 1980-2003 A- 42 A.2.4 Number of occurrences - Accommodation units Table 62 Accommodation units. UKCS, 1980-89, 1990-92 A- 43 Table 63 Accommodation units. UKCS, 1993-1996 A- 44 Table 64 Accommodation units. UKCS, 1997-1999 A- 45 Table 65 Accommodation units. UKCS, 2000-2003 A- 46 Table 66 Accommodation units. UKCS, 1990-2003, 1980-2003 A- 47

TECHNICAL REPORT

Page A-5

A.2. 1 Occurrence frequencies - Mobile Drilling Units (MODUs) In the following tables the number of occurrences and corresponding frequencies for mobile drilling units are given per type of unit and year/period.

Table 25 Drilling jackups. UKCS, 1980-89, 1990-92. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period Year

1980-89 1990 1991 1992

Type of event N F N F N F N F

Anchor failure 3 0.015 - - 1 0.034 1 0.034

Blowout - - - - 1 0.034 - -

Capsize 2 9.7•10-3 - - - - - -

Collision 2 9.7•10-3 - - 2 0.067 2 0.069

Contact 22 0.107 7 0.252 6 0.202 10 0.345

Crane 95 0.461 26 0.935 32 1.077 14 0.483

Explosion 3 0.015 - - - - - -

Falling object 82 0.398 22 0.791 33 1.111 13 0.448

Fire 15 0.073 4 0.144 - - 5 0.172

Foundering 1 4.9•10-3 - - - - - -

Grounding 1 4.9•10-3 - - - - - -

Helicopter 1 4.9•10-3 - - - - - -

Leakage - - 1 0.036 1 0.034 - -

List 2 9.7•10-3 1 0.036 1 0.034 1 0.034

Machinery - - - - - - - -

Off position 4 0.019 1 0.036 - - 1 0.034

Spill/release 18 0.087 7 0.252 2 0.067 14 0.483

Structural 14 0.068 1 0.036 1 0.034 1 0.034

Towing/towline 5 0.024 3 0.108 - - 1 0.034

Well problem 16 0.078 2 0.072 2 0.067 2 0.069

Other 2 0.010 - - 1 0.034 1 0.034

TECHNICAL REPORT

Page A-6

Table 26 Drilling jackups. UKCS, 1993-96. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1993 1994 1995 1996

Type of event N F N F N F N F

Anchor failure - - 1 0.046 - - - -

Blowout - - 1 0.046 - - - -

Capsize - - - - - - - -

Collision 1 0.038 - - - - - -

Contact 4 0.15 6 0.276 2 0.097 - -

Crane 12 0.451 18 0.829 12 0.58 15 0.652

Explosion - - 1 0.046 1 0.048 - -

Falling object 19 0.714 19 0.876 20 0.966 22 0.957

Fire 3 0.113 7 0.323 6 0.29 4 0.174

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - 1 0.048 - -

Machinery - - - - - - - -

Off position 1 0.038 - - - - - -

Spill/release 9 0.338 10 0.461 6 0.29 2 0.087

Structural 2 0.075 - - 1 0.048 1 0.043

Towing/towline - - - - - - - -

Well problem - - 3 0.138 4 0.193 7 0.304

Other - - - - 2 0.097 1 0.043

TECHNICAL REPORT

Page A-7

Table 27 Drilling jackups. UKCS, 1997-99. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1997 1998 1999

Type of event N F N F N F

Anchor failure 1 0.046 - - - -

Blowout 1 0.046 1 0.045 - -

Capsize - - - - - -

Collision - - - - - -

Contact 2 0.092 5 0.227 3 0.125

Crane 27 1.244 31 1.409 9 0.375

Explosion - - - - - -

Falling object 31 1.429 45 2.045 15 0.625

Fire 5 0.230 4 0.182 4 0.167

Foundering - - - - - -

Grounding - - - - - -

Helicopter - - - - - -

Leakage 1 0.046 - - - -

List - - - - - -

Machinery - - - - - -

Off position 1 0.042

Spill/release 3 0.138 6 0.273 9 0.375

Structural - - 1 0.045 1 0.042

Towing/towline - - - - - -

Well problem 14 0.645 30 1.364 8 0.333

Other 2 0.092 1 0.045 - -

TECHNICAL REPORT

Page A-8

Table 28 Drilling jackups. UKCS, 2000-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

2000 2001 2002 2003

Type of event N F N F N F N F

Anchor failure 1 0.045 - - - - - -

Blowout 1 - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - 1 0.043 2 0.088 2 0.087

Crane 6 0.268 17 0.736 25 1.101 19 0.823

Explosion - - - - - - - -

Falling object 15 0.670 22 0.952 27 1.189 23 0.996

Fire 1 0.045 3 0.130 1 0.044 - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release 6 0.268 5 0.216 5 0.220 4 0.173

Structural 2 0.090 1 0.043 - - - -

Towing/towline - - - - - - - -

Well problem 15 0.670 11 0.476 17 0.749 13 0.563

Other - - - - - - - -

TECHNICAL REPORT

Page A-9

Table 29 Drilling jackups. UKCS, 1990-2003. 1980-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period

1990-2003 1980-2003

Type of event N F N F

Anchor failure 5 0.015 8 0.015

Blowout 5 0.015 5 9.2•10-3

Capsize - - 2 3.7•10-3

Collision 5 0.015 7 0.013

Contact 50 0.148 72 0.133

Crane 263 0.779 358 0.659

Explosion 2 5.9•10-3 5 9.2•10-3

Falling object 326 0.966 408 0.751

Fire 47 0.139 62 0.114

Foundering - - 1 1.8•10-3

Grounding - - 1 1.8•10-3

Helicopter - - 1 1.8•10-3

Leakage 3 8.9•10-3 3 5.5•10-3

List 4 0.012 6 0.012

Machinery - - - -

Off position 4 0.012 8 0.015

Spill/release 88 0.261 106 0.195

Structural 12 0.036 26 0.048

Towing/towline 4 0.012 9 0.017

Well problem 128 0.379 144 0.265

Other 8 0.024 10 0.018

TECHNICAL REPORT

Page A-10

Table 30 Drilling semisubmersibles. UKCS, 1980-89, 1990-92. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period Year

1980-89 1990 1991 1992

Type of event N F N F N F N F

Anchor failure 50 0.146 19 0.412 21 0.426 11 0.228

Blowout 2 5.6•10-3 1 0.022 2 0.041 1 0.021

Capsize - - - - - - - -

Collision 2 5.6•10-3 1 0.022 - - - -

Contact 39 0.114 9 0.195 12 0.243 11 0.228

Crane 154 0.450 50 1.085 105 2.130 52 1.079

Explosion 8 0.023 2 0.043 3 0.061 1 0.021

Falling object 177 0.517 53 1.150 104 2.11 58 1.203

Fire 23 0.067 3 0.065 12 0.243 6 0.124

Foundering - - - - - - - -

Grounding 2 5.6•10-3 - - - - - -

Helicopter 3 8.9•10-3 - - - - - -

Leakage 6 0.018 4 0.087 4 0.081 1 0.021

List 1 2.9•10-3 1 0.022 3 0.061 1 0.021

Machinery - - - - 1 0.020 - -

Off position 9 0.026 2 0.043 5 0.101 2 0.041

Spill/release 29 0.085 9 0.195 14 0.284 9 0.187

Structural 14 0.041 3 0.065 3 0.061 1 0.021

Towing/towline 9 0.026 2 0.043 2 0.041 - -

Well problem 16 0.047 3 0.065 7 0.142 6 0.124

Other 5 0.015 4 0.087 7 0.142 - -

TECHNICAL REPORT

Page A-11

Table 31 Drilling semisubmersibles. UKCS, 1993-96. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1993 1994 1995 1996

Type of event N F N F N F N F

Anchor failure 18 0.407 5 0.139 5 0.145 17 0.445

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision 1 0.023 - - 3 0.087 1 0.026

Contact 8 0.181 4 0.111 2 0.058 3 0.079

Crane 16 0.362 12 0.333 44 1.279 48 1.257

Explosion - - - - 1 0.029 - -

Falling object 31 0.701 18 0.500 53 1.541 55 1.440

Fire 5 0.113 3 0.083 7 0.203 5 0.131

Foundering - - - - - - - -

Grounding - - - - - - 1 0.026

Helicopter 1 0.028 2 0.058 - -

Leakage 1 0.023 0 0.000 1 0.029 - -

List - - - - - - - -

Machinery - - - - - - - -

Off position 3 0.068 2 0.056 - - 3 0.079

Spill/release 6 0.136 8 0.222 5 0.145 11 0.288

Structural 1 0.023 - - 2 0.058 - -

Towing/towline - - 1 0.028 - - 3 0.079

Well problem 5 0.113 1 0.028 2 0.058 10 0.262

Other 4 0.090 2 0.056 - - - -

TECHNICAL REPORT

Page A-12

Table 32 Drilling semisubmersibles. UKCS, 1997-99. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1997 1998 1999

Type of event N F N F N F

Anchor failure 17 0.471 8 0.219 4 0.124

Blowout 5 0.139 - - - -

Capsize - - 1 0.027 - -

Collision - - 1 0.027 2 0.062

Contact 3 0.083 5 0.137 5 0.155

Crane 76 2.105 52 1.425 29 0.898

Explosion - - 1 0.027 - -

Falling object 93 2.576 63 1.726 65 2.012

Fire 4 0.111 3 0.082 7 0.217

Foundering - - 1 0.027 - -

Grounding - - - - - -

Helicopter - - - - - -

Leakage - - - - - -

List - - - - - -

Machinery - - - - - -

Off position 1 0.028 1 0.027 - -

Spill/release 13 0.36 7 0.192 9 0.279

Structural 5 0.139 4 0.110 1 0.031

Towing/towline 1 0.028 - - - -

Well problem 11 0.305 12 0.329 7 0.217

Other 2 0.055 - - 3 0.093

TECHNICAL REPORT

Page A-13

Table 33 Drilling semisubmersibles. UKCS, 2000-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

2000 2001 2002 2003

Type of event N F N F N F N F

Anchor failure 2 0.066 2 0.066 2 0.061 4 0.130

Blowout 1 0.033 1 0.033 - - - -

Capsize - - - - - - - -

Collision - - 1 0.033 - - - -

Contact 2 0.066 2 0.066 4 0.123 1 0.033

Crane 64 2.119 61 2.007 47 1.442 10 0.326

Explosion - - - - - - - -

Falling object 78 2.583 69 2.270 55 1.687 17 0.554

Fire 6 0.199 2 0.066 8 0.245 3 0.098

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage 1 0.033 - - - - - -

List 2 0.066 - - - - - -

Machinery - - 2 0.066 - - - -

Off position - - - - - - - -

Spill/release 10 0.331 6 0.197 8 0.245 8 0.261

Structural 1 0.033 - - - - - -

Towing/towline - - 1 0.033 - - - -

Well problem 11 0.364 7 0.230 13 0.399 8 0.261

Other - - 1 0.033 1 0.031 1 0.033

TECHNICAL REPORT

Page A-14

Table 34 Drilling semisubmersibles. UKCS, 1990-2003. 1980-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period

1990-2003 1980-2003

Type of event N F N F

Anchor failure 135 0.257 185 0.213

Blowout 11 0.021 13 0.015

Capsize 1 1.9•10-3 1 1.2•10-3

Collision 10 0.019 12 0.014

Contact 71 0.135 110 0.127

Crane 666 1.268 820 0.946

Explosion 8 0.015 16 0.018

Falling object 812 1.546 989 1.140

Fire 74 0.141 97 0.112

Foundering 1 1.9•10-3 1 1.2•10-3

Grounding 1 1.9•10-3 3 3.5•10-3

Helicopter 3 5.7•10-3 6 6.9•10-3

Leakage 12 0.023 18 0.021

List 7 0.013 8 9.2•10-3

Machinery 3 5.7•10-3 3 3.5•10-3

Off position 19 0.036 28 0.032

Spill/release 123 0.234 152 0.175

Structural 21 0.040 35 0.040

Towing/towline 10 0.019 19 0.022

Well problem 103 0.196 119 0.137

Other 25 0.048 30 0.035

TECHNICAL REPORT

Page A-15

Table 35 Drillships. UKCS, 1980-89, 1990-92. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period Year

1980-89 1990 1991 1992

Type of event N F N F N F N F

Anchor failure 1 0.357 - - 3 7.5 1 2.5

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - 1 2.5 - -

Crane 2 0.714 2 5 4 10.0

Explosion - - - - - - - -

Falling object 3 1.071 - - 2 5 5 12.5

Fire - - - - 1 2.5 - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - 1 2.5 - -

List - - - - - - - -

Machinery - - - - - - - -

Off position 1 0.357 - - - - - -

Spill/release 1 0.357 - - - - - -

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other 1 0.357 - - - - - -

TECHNICAL REPORT

Page A-16

Table 36 Drillships. UKCS, 1993-96. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1993 1994 1995 1996

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - - - - -

Crane 1 2.5 2 6.667 1 3.333 4 13.333

Explosion - - - - - - - -

Falling object 2 5 2 6.667 - - 5 16.667

Fire - - - - - - 1 3.333

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release - - - - - - - -

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other - - - - - - - -

TECHNICAL REPORT

Page A-17

Table 37 Drillships. UKCS, 1997-99. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1997 1998 1999

Type of event N F N F N F

Anchor failure - - - - - -

Blowout - - - - - -

Capsize - - - - - -

Collision - - - - - -

Contact - - - - - -

Crane 3 10.0 - - - -

Explosion - - - - - -

Falling object 3 10.0 - - - -

Fire - - - - - -

Foundering - - - - - -

Grounding - - - - - -

Helicopter - - - - - -

Leakage - - - - - -

List - - - - - -

Machinery - - - - - -

Off position - - - - - -

Spill/release 1 3.333 - - - -

Structural - - - - - -

Towing/towline - - - - - -

Well problem - - - - - -

Other - - - - - -

TECHNICAL REPORT

Page A-18

Table 38 Drillships. UKCS, 2000-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

2000 2001 2002 2003

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - - - - -

Crane - - 2 5.0 - - 1 1.0

Explosion - - - - - - - -

Falling object - - 2 5.0 - - 1 1.0

Fire - - - - - - - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - 1 1.429 - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release - - - - - - - -

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem - - 2 5.0 1 1.429 - -

Other - - 1 2.5 - - - -

TECHNICAL REPORT

Page A-19

Table 39 Drillships. UKCS, 1990-2003. 1980-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period

1990-2003 1980-2003

Type of event N F N F

Anchor failure 4 0.714 5 0.595

Blowout - - - -

Capsize - - - -

Collision - - - -

Contact 1 0.179 1 0.119

Crane 20 3.571 22 2.619

Explosion - - - -

Falling object 22 3.929 25 2.976

Fire 2 0.357 2 0.238

Foundering - - - -

Grounding - - - -

Helicopter - - - -

Leakage 2 0.357 2 0.238

List - - - -

Machinery - - - -

Off position - - 1 0.119

Spill/release 1 0.179 2 0.238

Structural - - - -

Towing/towline - - - -

Well problem 3 0.536 3 0.357

Other 1 0.179 2 0.238

TECHNICAL REPORT

Page A-20

A.2. 2 Occurrence frequencies - Mobile Production Units (MOPUs) In the following tables the number of occurrences and corresponding frequencies for mobile production units (MOPUs) are given per type of unit and year/period. The MOPUs comprise jackups, semi-submersibles and tension-leg platforms. Please observe that no events have been recorded for production jackups prior to year 2000.

Table 4 Production jackups. UKCS. 1980-2003. No. of occurrences per unit year. Source: All databases combined

0

Year Type of event N F

2000 Crane 5 2.5

2000 Falling object 6 3.0

2000 Spill/release 2 1.0

2000 Well problem 2 1.0

2001 Crane 1 0.5

2001 Falling object 3 1.5

2001 Fire 1 0.5

2001 Spill/release 7 3.5

2001 Well problem 1 0.5

2002 Crane 2 1.0

2002 Falling object 2 1.0

2003 Falling object 2 1.0

2003 Spill/release 1 0.5

Crane 8 0.582

Falling object 13 0.946

Fire 1 0.073

Spill/release 10 0.727

Average 1980-2003

Well problem 3 0.218

TECHNICAL REPORT

Page A-21

Table 41 Production semisubmersibles. UKCS, 1980-89, 1990-92. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period Year

1980-89 1990 1991 1992

Type of event N F N F N F N F

Anchor failure 4 0.222 2 0.500 - - 1 0.292

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact 2 0.111 - - 1 0.333 - -

Crane 10 0.556 - - 5 1.667 1 0.292

Explosion 2 0.111 1 0.250 - - - -

Falling object 11 0.611 1 0.250 5 1.667 1 0.292

Fire 6 0.333 2 0.500 - - - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position 1 0.056 - - - - - -

Spill/release 6 0.333 1 0.250 - - 1 0.292

Structural 3 0.167 - - - - - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other 1 0.056 - - - - - -

TECHNICAL REPORT

Page A-22

Table 42 Production semisubmersibles. UKCS, 1993-96. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1993 1994 1995 1996

Type of event N F N F N F N F

Anchor failure 1 0.250 - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - - - - -

Crane 1 0.250 2 0.428 3 0.600 2 0.400

Explosion - - - - - - - -

Falling object 1 0.250 1 0.214 2 0.400 2 0.400

Fire - - - - - - - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release 2 0.500 4 0.857 2 0.400 1.000 0.200

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other - - 1 0.214 - - - -

TECHNICAL REPORT

Page A-23

Table 43 Production semisubmersibles. UKCS, 1997-99. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1997 1998 1999

Type of event N F N F N F

Anchor failure - - - - - -

Blowout - - - - - -

Capsize - - - - - -

Collision - - - - - -

Contact - - - - 1 0.200

Crane 3 0.600 - - 1 0.200

Explosion - - - - - -

Falling object 4 0.800 1 0.200 1 0.200

Fire - - - - 3 0.600

Foundering - - - - - -

Grounding - - - - - -

Helicopter - - - - - -

Leakage - - - - - -

List - - - - - -

Machinery - - - - - -

Off position - - - - - -

Spill/release 7 1.400 1 0.200 8 1.600

Structural - - - - - -

Towing/towline - - - - - -

Well problem - - - - - -

Other 1 0.200 - - 1 0.200

TECHNICAL REPORT

Page A-24

Table 44 Production semisubmersibles. UKCS, 2000-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

2000 2001 2002 2003

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact 1 0.200

Crane 1 0.200 5 1.000 2 0.400 - -

Explosion - - - - - - - -

Falling object 1 0.200 7 1.400 4 0.800 - -

Fire 3 0.600 1 0.200 3 0.600 1 0.200

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release - - - - 12 2.400 11 2.200

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem 1 0.200 - - - - - -

Other 1 0.200 - - - - 1 0.200

TECHNICAL REPORT

Page A-25

Table 45 Production semisubmersibles. UKCS, 1990-2003. 1980-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period

1990-2003 1980-2003

Type of event N F N F

Anchor failure 4 0.062 8 0.098

Blowout - - - -

Capsize - - - -

Collision - - - -

Contact 3 0.047 5 0.061

Crane 26 0.406 36 0.439

Explosion 1 0.016 3 0.037

Falling object 31 0.484 42 0.512

Fire 13 0.203 19 0.232

Foundering - - - -

Grounding - - - -

Helicopter - - - -

Leakage - - - -

List - - - -

Machinery - - - -

Off position - - 1 0.012

Spill/release 90 1.404 96 1.169

Structural - - 3 0.037

Towing/towline - - - -

Well problem 1 0.016 1 0.012

Other 5 0.078 6 0.073

TECHNICAL REPORT

Page A-26

Table 46 Tension-leg platforms. UKCS, 1980-89, 1990-92. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period Year

1980-89 1990 1991 1992

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact 1 0.185 - - - - - -

Crane 19 3.506 4 4.000 9 9.000 8 8.000

Explosion - - - - - - - -

Falling object 15 2.768 3 3.000 10 10.000 9 9.000

Fire 3 0.554 3 3.000 - - - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release 3 0.554 2 2 1 1 - -

Structural 1 0.185 - - - - - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other 1 0.185 - - - - - -

TECHNICAL REPORT

Page A-27

Table 47 Tension-leg platforms. UKCS, 1993-96. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1993 1994 1995 1996

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - 1 1.000 - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - - - 1 1.000

Crane - - 3 3.000 4 4.000 1 1.000

Explosion - - - - - - 1 1.000

Falling object 2 2.000 3 3.000 5 5.000 1 1.000

Fire 2 2.000 1 1.000 - - 3 3.000

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - 1 1.000 - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release 1 1.000 1 1.000 3 3.000 1 1.000

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem - - 1 1.000 1 1.000 - -

Other - - - - - - - -

TECHNICAL REPORT

Page A-28

Table 48 Tension-leg platforms. UKCS, 1997-99. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1997 1998 1999

Type of event N F N F N F

Anchor failure - - - - - -

Blowout - - - - - -

Capsize - - - - - -

Collision - - - - - -

Contact - - - - - -

Crane 2 2.000 1 1.000 - -

Explosion - - - - - -

Falling object 2 2.000 2 2.000 - -

Fire - - - - - -

Foundering - - - - - -

Grounding - - - - - -

Helicopter - - - - - -

Leakage - - - - - -

List - - - - - -

Machinery - - - - - -

Off position - - - - - -

Spill/release - - 1 1.000 - -

Structural - - - - - -

Towing/towline - - - - - -

Well problem - - - - - -

Other - - - - - -

TECHNICAL REPORT

Page A-29

Table 49 Tension-leg platforms. UKCS, 2000-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

2000 2001 2002 2003

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - - - - -

Crane - - - - 7 17.500 - -

Explosion - - - - - - - -

Falling object - - 3 3.000 6 15.000 - -

Fire 2 2.000 - - 1 2.500 - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release 2 2.000 4 4.000 - - - -

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem 1 1.000 - - - - - -

Other - - - - - - - -

TECHNICAL REPORT

Page A-30

Table 50 Tension-leg platforms. UKCS, 1990-2003. 1980-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period

1990-2003 1980-2003

Type of event N F N F

Anchor failure - - - -

Blowout 1 0.081 1 0.056

Capsize - - - -

Collision - - - -

Contact 1 0.081 2 0.112

Crane 39 3.145 58 3.255

Explosion 1 0.081 1 0.056

Falling object 46 3.710 61 3.423

Fire 12 0.968 15 0.842

Foundering - - - -

Grounding - - - -

Helicopter 1 0.081 1 0.056

Leakage - - - -

List - - - -

Machinery - - - -

Off position - - - -

Spill/release 16 1.290 19 1.066

Structural - - 1 0.056

Towing/towline - - - -

Well problem 3 0.242 3 0.168

Other - - 1 0.056

TECHNICAL REPORT

Page A-31

A.2. 3 Occurrence frequencies - Monohull units In the following tables the number of occurrences and corresponding frequencies for monohull units are given per type of unit and year/period. The monohulls comprise both FSUs and FPSOs (both converted tankers and purpose-built units).

TECHNICAL REPORT

Page A-32

FPSOs - Both types

The following tables show the calculated frequencies for FPSOs irrespective of type of construction (i.e. converted or purpose-built)

Table 51 FPSOs. UKCS, 1980-89, 1990-92. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period Year

1980-89 1990 1991 1992

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - - - 1 1.000

Crane - - - - 1 1.000 - -

Explosion - - - - - - - -

Falling object - - - - 1 1.000 - -

Fire - - 1 1.000 - - - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release - - - - 1 1.000 3 3.000

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other - - - - 2 2.000 - -

TECHNICAL REPORT

Page A-33

Table 52 FPSOs. UKCS, 1993-96. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1993 1994 1995 1996

Type of event N F N F N F N F

Anchor failure 1 0.500 4 2.000 - - 1 0.235

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact 2 1.000 - - - - - -

Crane 3 1.500 1 0.500 2 0.615 1 0.235

Explosion - - 1 0.500 1 0.308 - -

Falling object 3 1.500 2 1.000 3 0.923 1 0.235

Fire 1 0.500 2 1.000 3 0.923 2 0.471

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter 1 0.500 - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position 1 0.500 - - - - - -

Spill/release 3 1.500 14 7.000 13 4 3 0.706

Structural - - 1 0.500 1 0.308 - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other - - 2 1.000 1 0.308 - -

TECHNICAL REPORT

Page A-34

Table 53 FPSOs. UKCS, 1997-99. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1997 1998 1999

Type of event N F N F N F

Anchor failure - - - - 3 0.240

Blowout - - - - - -

Capsize - - - - - -

Collision - - - - - -

Contact 1 0.152 2 0.211 2 0.160

Crane 10 1.520 3 0.316 6 0.480

Explosion - - - - - -

Falling object 10 1.520 5 0.526 8 0.640

Fire - - 1 0.105 4 0.320

Foundering - - - - - -

Grounding - - - - - -

Helicopter - - - - - -

Leakage - - - - 1 0.080

List - - - - 1 0.080

Machinery - - - - - -

Off position - - - - -

Spill/release 4 0.608 11 1.158 32 2.560

Structural - - 1 0.105 1 0.080

Towing/towline - - - - - -

Well problem - - - - - -

Other 1 0.152 - - 9 0.720

TECHNICAL REPORT

Page A-35

Table 54 FPSOs. UKCS, 2000-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

2000 2001 2002 2003

Type of event N F N F N F N F

Anchor failure - - - - - - 2 0.154

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - 1 0.077 1 0.077

Crane 7 0.538 7 0.528 6 0.462 4 0.308

Explosion - - - - - - - -

Falling object 11 0.846 7 0.528 5 0.385 7 0.539

Fire 9 0.692 6 0.453 7 0.539 4 0.308

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - 1 0.077

Off position - - - - - - - -

Spill/release 49 3.769 23 1.736 39 3.000 41 3.154

Structural 1 0.077 - - - - - -

Towing/towline - - - - - - - -

Well problem - - 1 0.075 - - 1 0.077

Other 3 0.231 2 0.151 2 0.154 1 0.077

TECHNICAL REPORT

Page A-36

Table 55 FPSOs. UKCS, 1990-2003. 1980-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period

1990-2003 1980-2003

Type of event N F N F

Anchor failure 11 0.115 11 0.113

Blowout - - - -

Capsize - - - -

Collision - - - -

Contact 10 0.105 10 0.103

Crane 51 0.535 51 0.525

Explosion 2 0.021 2 0.021

Falling object 63 0.661 63 0.649

Fire 40 0.420 40 0.412

Foundering - - - -

Grounding - - - -

Helicopter 1 0.011 1 0.010

Leakage 1 0.011 1 0.010

List 1 0.011 1 0.010

Machinery 1 0.011 1 0.010

Off position 1 0.011 1 0.010

Spill/release 236 2.476 236 2.431

Structural 5 0.052 5 0.052

Towing/towline - - - -

Well problem 2 0.021 2 0.021

Other 23 0.241 23 0.237

TECHNICAL REPORT

Page A-37

In the table below the frequencies for purpose-built and converted FPSOs are shown separately for the period 1980-2003.

Table 56 FPSOs. Type of event vs. type of FPSO. UKCS, 1980-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Type of construction

Purpose-built Converted

Type of event N F N F

Anchor failure 11 0.145 - -

Blowout - - - -

Capsize - - - -

Collision - - - -

Contact 10 0.131 - -

Crane 38 0.499 12 0.571

Explosion 2 0.026 - -

Falling object 49 0.644 14 0.667

Fire 31 0.408 9 0.429

Foundering - - - -

Grounding - - - -

Helicopter 1 0.013 - -

Leakage 1 0.013 - -

List 1 0.013 - -

Machinery - - - -

Off position 1 0.013 - -

Spill/release 171 2.248 65 3.095

Structural 3 0.039 2 0.095

Towing/towline - - - -

Well problem 2 0.026 - -

Other 18 0.237 4 0.191

TECHNICAL REPORT

Page A-38

FSUs

The tables below show the calculated frequencies for FSUs.

Table 57 FSUs. UKCS, 1980-89, 1990-92. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period Year

1980-89 1990 1991 1992

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - - - - -

Crane 2 0.253 - - - - - -

Explosion - - - - - - - -

Falling object 2 0.253 1 1 1 1 - -

Fire 1 0.126 - - - - - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position 1 0.126 - - - - - -

Spill/release 1 0.126 - - - - - -

Structural 1 0.126 - - - - - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other - - - - - - - -

TECHNICAL REPORT

Page A-39

Table 58 FSUs. UKCS, 1993-96. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1993 1994 1995 1996

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - - - - -

Crane 1 0.429 - - - - - -

Explosion - - - - - - - -

Falling object 1 0.429 - - - - - -

Fire - - - - - - - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release - - 1 0.292 1 0.333 - -

Structural - - - - 1 0.333 - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other - - 1 0.292 1 0.333 - -

TECHNICAL REPORT

Page A-40

Table 59 FSUs. UKCS, 1997-99. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

1997 1998 1999

Type of event N F N F N F

Anchor failure - - - - - -

Blowout - - - - - -

Capsize - - - - - -

Collision - - - - - -

Contact - - - - - -

Crane - - - - 1 0.500

Explosion - - - - - -

Falling object - - - - - -

Fire - - - - - -

Foundering - - - - - -

Grounding - - - - - -

Helicopter - - - - - -

Leakage - - - - - -

List - - - - - -

Machinery - - - - - -

Off position - - - - - -

Spill/release - - - - - -

Structural - - - - - -

Towing/towline - - - - - -

Well problem - - - - - -

Other - - - - - -

TECHNICAL REPORT

Page A-41

Table 60 FSUs. UKCS, 2000-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Year

2000 2001 2002 2003

Type of event N F N F N F N F

Anchor failure - - - - - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact 1 0.481 1 0.333 2 0.667 - -

Crane 1 0.481 1 0.333 - - - -

Explosion - - - - - - - -

Falling object 1 0.481 1 0.333 - - 1 0.333

Fire - - - - - - - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release - - 1 0.333 - - - -

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other - - - - - - - -

TECHNICAL REPORT

Page A-42

Table 61 FSUs. UKCS, 1990-2003. 1980-2003. No. of occurrences and occurrence frequencies (per unit year). Source: All databases combined Period

1990-2003 1980-2003

Type of event N F N F

Anchor failure 1 0.030 1 0.025

Blowout - - - -

Capsize - - - -

Collision - - - -

Contact 4 0.122 4 0.098

Crane 4 0.122 6 0.147

Explosion - - - -

Falling object 6 0.183 8 0.196

Fire - - 1 0.025

Foundering - - - -

Grounding - - - -

Helicopter - - - -

Leakage - - - -

List - - - -

Machinery - - - -

Off position - - 1 0.0245

Spill/release 3 0.091 4 0.098

Structural 1 0.030 2 0.049

Towing/towline

Well problem

Other 2 0.061 2 0.049

TECHNICAL REPORT

Page A-43

A.2. 4 Number of occurrences - Accommodation units Since no exposure data for these type of units are available, only the number of occurrences are given (i.e. no frequencies). These units comprise both the jackup and semisubmersible types.

Table 62 Accommodation units. UKCS. 1980-89, 1990-92. No. of occurrences. Source: All databases combined Period Year

1980-89 1990 1991 1992

Type of event Jackup Semisub. Jackup Semisub. Jackup Semisub. Jackup Semisub.

Anchor failure - 3 - 1 - 1 - 4

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact 2 3 - 1 - - - 1

Crane 2 6 - 3 - 3 - 6

Explosion - 1 - - - - - -

Falling object 3 11 - 6 - 5 - 6

Fire - 1 - 1 - 2 - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - 2 - 1 - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - 2 - 2 - 1 - 1

Spill/release - - - - - - - -

Structural 1 1 2 2

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other - 1 - - - - - 1

TECHNICAL REPORT

Page A-44

Table 63 Accommodation units. UKCS, 1993-96. No. of occurrences. Source: All databases combined Year

1993 1994 1995 1996

Type of event Jackup Semisub. Jackup Semisub. Jackup Semisub. Jackup Semisub.

Anchor failure - 6 - 6 - 1 2 -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact - - - - 1 - - -

Crane - 4 - 1 1 - 3 -

Explosion - - - - - - - -

Falling object - 7 - - 1 2 3 -

Fire - 1 - 3 - 1 - -

Foundering - - - - - - - -

Grounding - - - 1 - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - 1

Machinery - 1 - - - - - -

Off position - 4 - 1 - - - -

Spill/release - - - - 1 - - -

Structural - - - - 1 - - -

Towing/towline - 1 - - - - - -

Well problem - - - - - - - -

Other - - - - - - - -

TECHNICAL REPORT

Page A-45

Table 64 Accommodation units. UKCS, 1997-99. No. of occurrences. Source: All databases combined Year

1997 1998 1999

Type of event Jackup Semisub. Jackup Semisub. Jackup Semisub.

Anchor failure - 1 - - - -

Blowout - - - - - -

Capsize - - - - - -

Collision - - - - - -

Contact - 1 - - - -

Crane - 1 - - - -

Explosion - - - - - -

Falling object - 1 - - - -

Fire - - - 1 - -

Foundering - - - - - -

Grounding - - - - - -

Helicopter - - - - - -

Leakage - - - - - -

List - - - - - -

Machinery - - - - - -

Off position - - - - - -

Spill/release - - - - - -

Structural - - - - - -

Towing/towline - - - - - -

Well problem - - - - - -

Other - - - - - -

TECHNICAL REPORT

Page A-46

Table 65 Accommodation units. UKCS, 2000-2003. No. of occurrences. Source: All databases combined Year

2000 2001 2002 2003

Type of event Jackup Semisub. Jackup Semisub. Jackup Semisub. Jackup Semisub.

Anchor failure - - - 1 - - - -

Blowout - - - - - - - -

Capsize - - - - - - - -

Collision - - - - - - - -

Contact 1 - - - - - - -

Crane - - - - - - - -

Explosion - - - - - - - -

Falling object - - - - 1 - - -

Fire - - - - - - - -

Foundering - - - - - - - -

Grounding - - - - - - - -

Helicopter - - - - - - - -

Leakage - - - - - - - -

List - - - - - - - -

Machinery - - - - - - - -

Off position - - - - - - - -

Spill/release - - - - - - - -

Structural - - - - - - - -

Towing/towline - - - - - - - -

Well problem - - - - - - - -

Other - - - - - - - -

TECHNICAL REPORT

Page A-47

Table 66 Accommodation units. UKCS, 1990-2003, 1980-2003. No. of occurrences. Source: All databases combined Type of construction

1990-2003 1980-2003

Type of event Jackup Semisub. Jackup Semisub.

Anchor failure 2 21 2 24

Blowout - - - -

Capsize - - - -

Collision - 1 - 1

Contact 2 3 4 6

Crane 4 18 6 24

Explosion - - - 1

Falling object 5 27 8 38

Fire - 9 - 10

Foundering - - - -

Grounding - 1 - 1

Helicopter - 1 - 3

Leakage - 1 - 1

List - 1 - 1

Machinery - 1 - 1

Off position - 9 - 11

Spill/release 1 - 1 0

Structural 1 4 2 5

Towing/towline - 1 - 1

Well problem - - - -

Other - 1 - 2

- o0o -

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