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Summary report on the OSD Hydrocarbon Release Reduction
Hazardous Installations Directorate
Offshore Division
SPC/TECH/OSD/27
(Partially Open)
Summary report on the OSD Hydrocarbon Release Reduction
Campaign, April 2000 to March 2004
Date of issue: March 2005
Executive summary
Introduction
Release severity classification
Overall hydrocarbon numbers and severity distribution
Benchmarking
Size distributions
Analytical taxonomy
Operation mode
Hydrocarbon type
Release sites
Release causes
Failed safeguards
Additional safeguards
Remedial measures put in place during the campaign
Industry support
The way ahead
References
Table 1 - Numerical severity classification criteria
Table 2 - Offshore hydrocarbon releases reported under RIDDOR
from 1st April 2003 to 31st March 2004
Table 3 - Annual number of major, significant and minor offshore
releases reported under RIDDOR from 1993 / 1994 to 2003 / 2004
ÎTable 4 – Major / significant release rates per manned production
installation
Table 5 – Installations with 3 or more major and significant
hydrocarbon release in the reference periodÍ
Table 6 – Release analysis taxonomy
Fig 1 – Minor liquid releases – size distribution
Fig 2 – Significant liquid releases – size distribution
Fig 3 - All releases by operating mode
Fig 4 – All releases by hydrocarbon type
Fig 5 – All releases by release site
Fig 6 – Immediate causes – all releases
Fig 7 – Underlying causes – all releases
Annex 1 - Summary of 2003/4 Major Releases
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
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Executive summary
This document summarises the results from a four year campaign by the Offshore
Division (OSD) of the UK Health and Safety Executive to reduce the number of major
and significant offshore hydrocarbon releases by 50% compared to a 1999 / 2000
baseline when there were 139 such releases, 12 majors and 127 significants.
It also summarises the analysis of data regarding the size, type and cause of
releases which was obtained over two 12 month mandatory release investigation
projects in 2000/1 and 2003/4. Remedial measures put in place to try to improve the
position with respect to the most frequent causes of hydrocarbon release are also
discussed, as is the contribution made by the industry in support of the campaign.
The ‘end of campaign’ results showed a 56% reduction in major releases, a 28%
reduction in significant releases and a 30% reduction in the two categories
combined. The overall reduction shows a deterioration from the position at the end
of 2002/3 when the reduction had reached nearly 40%. Over-confidence that the
target would be met is seen as a significant factor influencing the 2003/4 increase in
release numbers. Minor releases have risen over the course of the campaign but
this is seen predominately as a correction to earlier years when there was significant
under-reporting of this class of release.
Comparison on the relatively crude ‘per manned installation’ basis shows that over
two thirds of companies had seen an improvement in release performance from
2000/1 to 2003/4. Indications from both this data and from information on the
individual installations with the highest number of major and significant releases in
years 2000/1 and 2003/4 suggest that the improvement in performance has been
most marked amongst smaller companies.
Both the 2000/1 and 2003/4 releases were analysed by operating mode, release
site, release mechanism, immediate and underlying causes, and failed safeguarding
systems. Potential additional safeguarding systems were also identified in some
cases. The majority of releases in both years involved gas and occurred during
normal production. Pipework was the main release site, with small bore piping a
significant contributor.
The most frequent immediate cause in 2003/4 was corrosion / erosion at 23% of all
releases, followed by degradation of material properties and incorrect installation
both at 16%. Operator error and procedural problems accounted for around 70% of
the 2003/4 releases from pipes or valves opened to the atmosphere. Nearly 60% of
all the 2003/4 releases had hardware related immediate causes, the remainder being
‘software’ or human-factor related. Comparative figures for the 2000/1 releases are
given. Inadequate inspection / condition monitoring featured strongly in the 2003/4
underlying causes, as did inadequate design.
The main failed safeguard identified in both years was inspection / condition
monitoring, suggesting that effective plant and operation status checks, along with
good personnel supervision, are significant factors in preventing releases.
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The report documents the industry ‘good practice’ guides produced during the
campaign as remedial measures to try to improve standards in identified problem
areas and comments on their initial impact whilst noting that many have only been
issued relatively recently.
Finally, the report notes the excellent co-operation from the offshore industry with the
campaign and describes some of the supporting activities at both the company and
trade association level.
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Introduction
1.
In April 2000, OSD launched an Offshore Hydrocarbon Release Reduction
Campaign. This was targeted at obtaining a 50% reduction in the annual number of
RIDDOR reportable offshore hydrocarbon releases in the major and significant
categories (see Para 6 below) by April 2004, compared with the comparable
baseline figures of 12 ‘majors’ and 127 ‘significants' in year 1999 / 2000.
2.
The campaign consisted of two parallel projects:
a)
one based on the mandatory investigation of all RIDDOR reportable
incidents involving hydrocarbon release on offshore installations,
b)
the second involving a programme of planned process integrity
inspections for all normally attended production platforms.
3.
The purpose if this report is to:
a)
provide the offshore industry with the results on hydrocarbon release
numbers for the duration of the campaign,
b)
provide the offshore industry and OSD inspectors with analysis data
from the incident investigation reports. In this context, the document should
be seen as an initial reports as there are many additional factors which time
and data processing constraints have currently excluded from the analysis,
c)
highlight broad problem areas which during the life of the project have
led to release of hydrocarbon, as a means of prioritising those areas where
further work on formulating and sharing good practice within the industry
would be most beneficial.
d)
provide an indication of the initial impact achieved by the various
industry ‘good practice’ guides put in place over the duration of the campaign.
4.
The investigation project ran for two separate 12 month periods from 1st April
2000 to 31st March 2001 and again from 1st April 2003 to 31st March 2004. During
this period OSD inspectors were required to investigate all offshore RIDDOR
reportable hydrocarbon releases, the extent of the investigation varying with the size
of the releases. To concentrate on the more serious releases, the main offshore
effort was directed at the investigation of gas and 2 phase releases greater than
25kg and liquid releases greater than 250kg (this broadly equates to releases in the
‘major’ category and upper quartile ‘significant’ releases as described below).
Smaller releases were investigated by gathering information from the dutyholder’s
own investigations. In order to obtain a description of the release mechanism and
identify the root causes and proposed remedial measures.
5.
The inspection project operated over the full 4 years of the campaign and
involved a 10 element rolling inspection programme for all normally attended
production platforms. The elements addressed included aspects such as the
general arrangements for the management of process safety, the control of small
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bore tubing and flexible hoses and the management of isolations and change
control. Full details of all the elements together with a summary of the main generic
findings relating to each of the elements are given in Ref 1.
Release severity classification
6.
All hydrocarbon releases reported to OSD under RIDDOR are classified in
terms of 3 severity categories: major, significant and minor. The definitions of the
categories are as follows:
Major – those with the potential to quickly impact outwith the local area e.g.
affect the Temporary Refuge, escape routes, or escalate to other areas of the
installation causing serious injury or fatalities.
Significant – those with the potential to cause serious injury or fatality to
personnel within the local area and to escalate within that local area, e.g. by
causing structural damage, secondary leaks or damage to safety systems.
Minor – those with the potential to cause serious injury to personnel in the
immediate vicinity, but no potential to escalate or cause multiple fatalities.
7.
Classification of releases is achieved through the use of numerical severity
criteria (in terms of release size, release rate and duration). The criteria used were
agreed with the offshore industry some years ago in conjunction with the
development of the Hydrocarbon Release Database, and are given in Table 1.
Overall hydrocarbon numbers and severity distribution
8.
The number of offshore hydrocarbon releases reported to OSD for 2003/4
under RIDDOR are shown in Table 2 together with the respective severity
classifications. Comparative figures for the ten previous years including the baseline
year 1999 / 2000 are shown in Table 3.
9.
In terms of major and significant releases, the figures indicate:
a)
A fairly steady reduction in the number of major releases from 12 in the
baseline year to 5 in 2003/4. The four years of the campaign were in fact the
first ones that single figure major release numbers had been achieved.
Overall, there was a 56% reduction in the number of major releases. Given
that it is the major releases which have the greatest potential to give rise to
rapidly escalating events, this is a particularly encouraging improvement
especially when compared to the long term average of 15 to 20 major
releases per year.
b)
The number of significant releases fell from 127 in 1999 / 2000 to 92 in
2003/4 representing a 28% reduction against baseline. However the overall
picture was more complicated in that the first 3 years of the campaign saw a
rapid reduction in the number of significant releases. The 2002/3 year end
total of 79 gave a reduction against baseline of just under 40%. Performance
then fell away in 2003/4, the final year of the campaign. Possible reasons for
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the 2003 / 2004 deterioration are discussed in Para 12.
c)
The combined number of major and significant releases fell from 139 in
1999 / 2000 to 97 in 2003/4, a 30% overall reduction against baseline. Again
the overall reduction was marred by a deteriorating performance in 2003/4,
the reduction having been 39% at the end of 2002/3.
10.
The number of minor releases reported in 2003/4 was 172 having seen a
steady rise from 99 in 1999 / 2000. However is believed that the result mainly
represents an increase in reporting activity as a result of greater awareness and
scrutiny of the reporting process, rather than an increase in the number of such
incidents actually taking place.
The OSD Hydrocarbon Release Reduction
Campaign has been supplemented by campaigns from a number of individual
companies and this undoubtedly increased awareness of reporting requirements
across the industry. Anecdotal evidence suggests that minor release reports have
been received for a wide range of small releases which would not have been
considered for reporting prior to the commencement of the campaign.
11.
There have also been doubts in the past as to the completeness and reliability
of the reporting of minor releases. For example, minor releases have shown by far
the greatest year-to-year variability, with swings of up to 50% being recorded. This
uncertainty was one of the major reasons that the release reduction target was
formulated just in terms of major and significant releases. In order to try to promote
both greater clarity and consistency in the RIDDOR reporting of smaller hydrocarbon
releases, a joint UKOOA / HSE reporting guide (Ref 2) was produced during the
course of the campaign.
12.
As noted in Para 9, one disappointing feature of the campaign has been the
pronounced deterioration in performance of the final year. A possible significant
reason behind the deterioration is considered to be a degree of over-confidence that
the targets would be met following the excellent progress made over the first 3 years
and that it was time for some dutyholders to focus on new challenges elsewhere in
their offshore operations. This attitude manifested itself in actions such as the early
abandonment of leak reduction teams and removal of reduction targets by individual
companies.
Benchmarking
13.
An output from the initial 2000/1 release investigation project was the
production of a comparative table of major and significant hydrocarbon release rates
on a ‘per manned installation’ basis for different dutyholders. It was recognised that
the rates derived only gave a fairly crude measure of safety performance in that, for
example, they treated all normally manned platforms as having an equal number of
potential leak sources, whereas in reality the installations varied in size and
complexity and hence in the number of potential leak sources.
14.
Subject to these caveats the data indicated a wide range in performance
between dutyholders, the worst having a release rate more than 6 times that of the
best. 57% of dutyholders had a release rate of 1 or below, 30% a rate of 2 or above.
On the basis of this information, it appeared that significant reductions in overall
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hydrocarbon release numbers could be secured if the performance of the worst
dutyholders could be brought up to that of the best, through methods such as intercompany benchmarking, sharing of good practice etc.
15.
Significant company mergers and ownership changes have made it difficult to
monitor performance trends for all the companies identified in the 2000/1 survey.
However, for those dutyholders where trend monitoring is possible, the figures are
given in Table 4.
16.
This indicates a general narrowing of performance differentials between
dutyholders and a broadly improving trend for release rates over the duration of the
campaign. For example, only three dutyholders had higher release rates in 2003/4
than in 2000/1, whilst eleven of the sixteen showed an improvement.
17.
Table 5 lists those installations experiencing 3 or more major or significant
hydrocarbon releases in 2000/1 and 2003/4.
18.
No installation appears in both the 2000/1 and 2003/4 lists. As a broad
generalisation, there are a disproportionate number of installations from smaller
dutyholders in the 2000/1 list whereas the 2003/4 has a greater proportion of
installations from larger dutyholders. This produces a good measurement of
agreement with data from Table 4 in that in 2000/1 the higher hydrocarbon release
rates were mainly associated with smaller dutyholders but since then their
performance has improved significantly to the extent of their equalling or even
surpassing some of their larger counterparts. It would appear that the ‘over
confidence’ factor mentioned in Para 12 has been largely centred around the larger
dutyholders, who initially were ‘well ahead of the game’ with respect to leak reduction
programmes.
Size distributions
19.
The three different severity categories (major, significant and minor) into
which the hydrocarbon releases are classified have quite wide size bands (see Table
1). For example, the ‘significant liquid release’ category ranges from 60 to 9000kg of
liquid. In practice, the release sizes reported during the project have been heavily
skewed toward the bottom end of the relevant ranges.
20.
The effect for 2000/1 minor and significant liquid releases can be seen in Figs.
1 and 2. For minor releases, 86% of releases were smaller than half the upper limit
for the category (60kg), and 65% of releases were smaller than one sixth the upper
limit. For significant liquid releases, 96% of releases were less than half the upper
limit (9000kg), and 80% were less than one sixth the upper limit. The corresponding
2003/4 figures are 83% and 63%, for minor releases and 88% and 83% for
significant releases.
21.
A similar pattern was found for significant gas and 2 phase releases, although
for a minor gas and 2 phase releases the distribution was more even across the size
range. The average size of a significant gas release in 2000 / 2001 was 42kg as
compared with 39.1kg in 2003/4.
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22.
The largest gas or 2 phase release on a manned installation was around
3350kg of hydrocarbon in 2000/1 and 2500kg in 2003/4. The largest liquid release
on a manned installation was around 6000kg in 2000/1 and 5000kg in 2003/4.
Analytical taxonomy
23.
To try to make maximum use of the information from the incident investigation
reports, the data in the reports has been classified in terms of causal factors relating
to:
a)
Operating mode,
b)
Release site,
c)
Release mechanism
d)
Immediate cause(s)
e)
Underlying cause(s)
f)
Failed safeguarding system
g)
Potential new or additional safeguarding systems that could have
prevented the incident.
24.
Each of these primary factors has then been developed in terms of secondary
factors. For example, the following secondary factors have been associated with the
primary factor ‘operating mode’.
a)
Start-up / re-instatement
b)
Normal production
c)
Abnormal production
d)
Maintenance
e)
Shutdown / shutting down
f)
Construction
g)
Well operations / drilling
h)
Testing / sampling
i)
Pigging
25.
The complete taxonomy employed is given in Table 6. It is essentially the
same as that employed in the earlier OTH 2001 055 (Ref 3) report but with the
addition of a small number of additional fields (e.g. temporary repair) under release
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sites. Where relevant, an attempt has been made to harmonise the taxonomy with
that used in the current OIR 12 reporting system. Nevertheless it is recognised that
there are many different taxonomies (in terms of primary and secondary factors) that
could be used, and that the current system may be modified for the purposes of
more detailed analysis – see para 3(b).
26.
Annex 1 contains a summary of each of the 5 major incidents that occurred in
2003/4.
Operation mode
27.
The percentage of incidents occurring during different operating modes in
2000/1 and 2003/4 are indicated in Fig 3. As might be expected, incidents occurring
during normal production provided the majority of releases. The 2003/4 normal
production proportion was 61% as against 57% in 2000/1. The next highest
category was start-up / re-instatement with 21% in 2003/4 as compare with 13% in
2000/1. Then followed maintenance at 8% (13% in 2000/1) and well operations /
drilling at 5% (8%in 2000/1). The increase in the start-up / re-instatement category is
noticeable and raises questions as to the adequacy of some pre-start up checks.
69% of releases in this category had operator error / incorrect installation or
inadequate isolation / procedures as immediate causes.
Hydrocarbon type
28.
The distribution of incidents by hydrocarbon type is shown in Fig 4. 51% of
the 2003/4 incidents were gas releases and 29.5% oil releases. The proportion of oil
releases has risen slightly in recent years (c.f 23% oil in 2000/1) in line with the
increases in the number of reported minor releases which tend to be predominately
oil. Release of other hydrocarbon types were much less frequent, the most common
being diesel at 6% (6% in 2000/1), condensate at 9% (8% in 2000/1) and 2 phase
fluids 2.6% (3% in 2000/1). In terms of major releases, all of the 5 reported in
2003/4 were either gas (4) or 2 phase (1), indicating that it is generally releases of
these types that pose the greatest threat, given their potential to form flammable
vapour clouds. 76% of the significant releases in 2003/4 also involved gas or 2
phase fluids (68% in 2000/1), compared with just 14% involving release of oil.
Release sites
29.
The 2003/4 incidents were analysed for the site of each release,
differentiating between major components such as vessels, pipework and valves,
and between generic site types such as flanges, seals and open ends. The results
are shown in Fig 5 which also shows the comparative 2000 / 2001 figures. The
proportions are generally similar between the two years. Pipework was the largest
contributor, being involved in 56% of all releases. Within that category small bore
piping was associated with 20% of releases. Valves were involved in 17% of
releases and vessels in 8%.
30.
The detailed findings also indicate the following:
a)
despite issuance in 2000 of the UKOOA / Institute of Petroleum ‘good
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practice’ guide on small bore tubing systems (Ref 4) releases associated with
small bore tubing systems actually rose both in percentage terms (from 18%
in 2000/1 to 20% in 2003/4) and in terms of overall numbers. This is
particularly disappointing and indicates that much more needs to be done to
improve standards and competency in this important area. 70% of the
associated releases were from connections and the rest from the pipe body.
75% of the releases were classified as minor and 25% as significant.
b)
12.4% of all releases were from flanges. This represents a decrease in
terms of both percentage (15% in 2000/1) and overall numbers and indicates
that the UKOOA / Institute of Petroleum guide on bolted pipe joints (Ref 5)
may be beginning to have a beneficial effect.
c)
21.9% of the 2003 / 2004 releases were from the body of a pipe, vessel
or valve, mostly caused by mechanical degradation including, for examples,
corrosion and erosion (20% in 2000/1).
d)
16.7% of 2003/4 releases were from seals and packing (14% in
2000/1).
e)
3.8% of 2003/4 releases were from flexible hoses compared to 4% in
2000/1. The joint UKOOA / Institute of Petroleum good practice guide on
flexible hoses (Ref 6) was only issued in January 2003 so it was probably too
early to expect any impact from the document.
f)
the percentage of releases associated with the temporary repairs was
3% which included one major release. This is a problem area that appears to
be growing in importance as there were no corresponding releases from this
source reported in 2000/1.
Release causes
31.
Analysis of the immediate causes of the 2003/4 releases is shown in Fig 6
which also displays the corresponding figures for 2000/1. Discussion of the analysis
needs to be immediately prefaced with comments on its depth. Analysis of most
releases usually indicates that there are many inter-related causes, i.e. it is multidimensional in terms of causation factors. However time and resource constraints
mean that the analysis reported here is essentially ‘one dimensional’ and attributes
the cause to that considered to have had the largest influence whilst recognising that
other causes probably also contributed. To gain maximum insight from the present
data would require a future full ‘multi dimensional’ analysis.
32.
The biggest single immediate cause in 2003/4 was corrosion / erosion at 23%
followed by degradation of material properties (16%), incorrect installation (16%),
fatigue / vibration (12%) and operator error (12%). In this context ‘degradation of
material properties’ means loss of integrity by failure of equipment which was
originally fit for purpose and was operated correctly, but excluding the specific
causes of corrosion, erosion, fatigue and vibration, which are recorded as separate
categories. For example, the category would include causation factors such as loss
of flexibility in flange gaskets and valve stem packing and general ‘wear and tear’.
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33.
The greater importance seen in 2000/1 of ‘operator error’ and ‘failure to follow
procedures’ as immediate cause of major releases was not repeated in 2003/4 and
the immediate causes were evenly spread around factors such as erosion, fatigue /
vibration, incorrect installation, degraded material properties and blockage.
34.
In terms of some of the principal release sites:
a)
the immediate cause of 40% of flange releases was incorrect
installation with degradation of material properties contributing a further 20%,
(28% and 20% respectively in 2000/1).
b)
the immediate cause of 35% of releases from small bore tubing was
fatigue / vibration, with a further contribution of 18% from incorrect installation
(29% and 15% respectively in 2000/1).
c)
47% of releases from open ends were due to inadequate procedures
and 25% to operator error
d)
the number of valve stem releases increased significantly from 2000/1
and 70% of the total were due to hardening of the stem packing (degradation
of material properties).
35.
The immediate causes can be divided into hardware-related and software
related issues:
Hardware
Internal corrosion
External corrosion
Erosion
Fatigue / vibration
Degradation of material properties
Inadequate equipment
Line blockage
Software
Inadequate isolation
Inadequate installation
Inadequate procedures
Operator error
Procedural violation
Nearly 60% of the releases had hardware-related immediate causes. Their biggest
single underlying cause was inadequate inspection / condition monitoring,
contributing to 48% of these incidents. Inadequate design was the next biggest
underlying cause at 26%, followed by inadequate maintenance (11%) and
inadequate installation (4%).
36.
For the remaining releases with software-related immediate causes, the
largest associated underlying cause was inadequate procedures at 26%.
Thereafter, the causes were more scattered with six contributing between 10% and
4%. In decreasing order these were inadequate design, inadequate inspection /
compliance monitoring, procedural violation, risk assessment, inadequate installation
and inadequate task specification.
37.
Of the underlying causes (Fig 7) the largest category in 2003/4 was
inadequate inspection / condition monitoring (35%) followed by inadequate design
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(21%), inadequate procedures (13%), inadequate competency (12%) and
inadequate maintenance (8%). The ‘inadequate design’ category frequently related
to inadequate piping support systems which left the pipes vulnerable to vibration and
fatigue problems.
Failed safeguards
38.
An attempt was made to identify safeguards which if they had operated
correctly might have prevented the releases. Failure to operate an effective
corrosion / erosion monitoring system was implicated in 28% of the 2003/4 releases
where identification was possible (10% in 2000/1). This confirms the increasing
importance of the issue of corrosion / erosion with ageing plant. Inadequate
inspection / condition monitoring was identified in a further 26% of incidents (32% in
2000/1), 12% of incidents in 2003/4 had procedural review as a failed safeguard
18% in 2000/1, 11% competency assurance (10% in 2000/1) and 8% design review
(15%in 2000/1).
Additional safeguards
39.
In some cases additional safeguards were suggested which might help
prevent future incidents. The main safeguards identified in both 2000/1 and 2003/4,
were improved implementation of the UKOOA guide on small bore pipeline and the
UKOOA joint integrity verification scheme.
Remedial measures put in place during the campaign
40.
One of the principal objectives for analysing release data during the campaign
has been to identify recurrent problem areas leading to release of hydrocarbons and
determine what measures could be put in place to try to reduce the frequency of their
occurrence. The main vehicle for potential remedial measures has been the
production of ‘good practice’ guides. These collate and publish information
considered to represent good practice in the industry with respect to the treatment of
particular issues, as a means of promoting better standards across all companies.
41.
It was recognised at the outset of the campaign that for maximum impact and
take-up any proposed remedial measures should be formulated and agreed as a
collaborative venture with the industry. The conduit for discussions with industry has
been the Release Reduction Workgroup set up by the United Kingdom Offshore
Operators Association (UKOOA).
42.
As discussed, the normal form of remedial measure has been the production
of industry ‘good practice’ guides addressing each of the individual problem areas,
supplemented where relevant by appropriate training. The format adopted to
produce good practice guides has been either
a)
The task to be undertaken by a dedicated group of industry nominees,
trade representatives and HSE.
b)
The work to be carried out by specialist consultancies jointly funded by
both industry and HSE.
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References 4 to 8 are examples of good practice guides produced via this route.
The guides were produced to specifically address a prioritised list of problem areas
identified by the investigation project. An important mechanism for promoting
awareness and usage of the documents has been for them to be incorporated into
HSE’s offshore inspection programmes.
Industry support
43.
An important feature of the campaign has been the degree of support that it
has received from the industry itself. From the outset of the campaign, every effort
was made to communicate to industry what was planned and why in order to
proceed as far as possible on a collaborative basis. This is a stance that has been
maintained throughout, with numerous talks being given to individual companies and
trade associations, annual feedback seminars being organised with the United
Kingdom Offshore Operators Association (UKOOA) and all documentation relating to
the campaign (such as the HSE Inspection Guidance Notes) being made freely
available.
44.
Some of the corresponding industry inputs include
a)
The setting up by UKOOA of a Release Reduction Workgroup to
support the campaign with representation from all operating companies.
b)
The production by the Release Reduction Workgroup of a ‘Reducing
Leaks – Raising Awareness’ video which was shown to the workforce on all
installations.
c)
Provision of staff to support the various workgroups set up to formulate
good practice in different problem areas.
45.
A summary of the output from the overall campaign has been produced in a
joint UKOOA / HSE publication ‘Hydrocarbon Release Reduction Toolkit’ (Ref 9).
This highlights the main problem areas identified during the campaign and indicates
the measures that companies can adopt to minimise the impact of these problem
areas on their own operations.
46.
Several individual companies also set up their own internal release reduction
campaigns to operate in parallel with HSE’s campaign. By the way of an example of
the level of effort that went into some of these individual campaigns, one company
a)
Produced a quarterly Leak Reduction Bulletin which was sent to all
staff.
b)
Provided monthly status reports on release numbers for all installations
which were issued across the company.
c)
Purchased portable ultrasonic leak detectors for all installations,
employed in the context of regular co-ordinated leak surveys on each
installation.
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d)
Sent 700 offshore personnel on a bolted joint assembly course
designed to supplement the UKOOA ‘good practice’ guide.
e)
Sent 900 offshore personnel on a compression fitting course and made
successful completion of the course a mandatory condition for future working
on such fittings.
f)
Sent 400 selected offshore personnel on a corrosion awareness
refresher courses and also produced a compact disk on the subject to
promote further platform discussion.
The way ahead
47.
Experience from the campaign clearly suggests that a sustained and
continuous improvement in annual offshore hydrocarbon release numbers can only
be achieved by a targeted and continuing effort by all relevant parties. Without this
focus, release numbers are likely to gradually increase back to previous levels.
48.
With this in mind, OSD will continue to regard annual offshore hydrocarbon
release numbers as a key performance indicator for the effectiveness of offshore
management controls. Accordingly annual release number targets have been
agreed with the industry for the period 2005/6 and 2006/7. These targets together
with many of the topics examined during the course of the inspection project will be
fed forward into a new 3 year Key Programme (KP3) which will address hydrocarbon
release issues under the slightly wider remit of ‘installation integrity’. It is clear from
the analysis of release sites and immediate and underlying causes that the new
programme will need to target issues such as
a)
the continuing high level of hydrocarbon release associated with small
bore tubing systems. (An increasing proportion of which seem to be
associated with vendor packages such as turbines).
b)
the high percentage of releases where corrosion / erosion was the
immediate cause. The monitoring of corrosion / erosion control systems will
become increasingly important as the offshore infrastructure continues to age.
c)
the effectiveness of systems for condition / inspection monitoring of the
plant including the relevant maintenance regimes.
Page 13 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
References
1.
Report on the findings from HSE’s process integrity National Inspection
Project (NIP), 2000 – 2004, SPC/TECH/OSD/28.
2.
Supplementary guidance for reporting hydrocarbon releases, UKOOA,
September 2002.
3.
Offshore Technology Report – OTO 2001/055. Report on the hydrocarbon
release incident investigation project .
1st April 2000 to 31st March 2001.
4.
Guidelines for the management of integrity of bolted pipe joints, UKOOA /
Institute of Petroleum, June 2002.
ISBN 1903003148.
5.
Guidelines for the management, design, installation and maintenance of small
bore tubing systems, UKOOA / Institute of Petroleum, June 2000.
ISBN 0852932758.
6.
Flexible hose management guidelines, UKOOA / Institute of Petroleum,
January 2003.
ISBN 1903003210.
7.
Guideline for the Avoidance of Vibration Induced Fatigue in Process
Pipework, Marine Technology Directorate.
ISBN 1870553373.
8.
Review of Corrosion Management for Offshore Oil and Gas Processing, UK
Health and Safety Executive, Report OTO 2001/044, August 2001.
ISBN 0717620964.
9.
Hydrocarbon release reduction toolkit, UKOOA / HSE, August 2004.
Page 14 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
Table 1 - Numerical severity classification criteria
TABLE 1
NUMERICAL SEVERITY CLASSIFICATION CRITERIA
MAJOR RELEASES
(i) Gas releases
EITHER
OR
Quantity released > 300 kg
Mass release rate > 1kg/s AND Duration > 5 min
(ii) Liquid releases (Oil / Condensate / Non-process)
EITHER
Quantity released > 9000kg
OR
Mass release rate > 10kg/s AND Duration > 15 min
(iii) 2-phase releases
EITHER
OR
Quantity of liquids released > 300kg
Liquids mass release rate > 1kg AND Duration > 5 min
MINOR RELEASES
(i) Gas release
EITHER
OR
Quantity released < 1kg
Mass release rate < 0.1kg/s AND Duration < 2 min
(ii) Liquid releases (Oil / Condensate / Non-process
EITHER
Quantity released < 60kg
OR
Mass release rate < 0.2kg/s AND Duration < 5 min
(iii) 2-phase releases
EITHER
OR
Quantity of liquids released < 1kg
Liquid release rate < 0.1kg AND Duration < 2 min
SIGNIFICANT RELEASES
Those releases lying between the limits for major and minor releases.
Page 15 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
Table 2 - Offshore hydrocarbon releases reported under RIDDOR from
1st April 2003 to 31st March 2004
By Process Type and Severity Type
Severity
Release Type
Total
Major
Significant
Minor
Non Process
0
5
28
33
Oil
0
13
63
76
Condensate
0
4
17
21
Gas
4
66
61
131
2-phase
1
4
3
8
GRAND TOTAL
5
92
172
269
Page 16 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
Table 3 - Annual number of major, significant and minor offshore releases reported under RIDDOR from 1993 /
1994 to 2003 / 2004
93/94
94/95
95/96
96/97
97/98
98/99
99/00
00/01
01/02
02/03
03/04
Major
24
20
20
19
13
15
12
8
4
6
5
Significant
151
194
134
129
139
134
127
117
105
79
92
Minor
96
111
58
78
66
85
99
145
134
144
172
Severity
BASELINE
YEAR
Page 17 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
Table 4 – Major / significant release rates per manned production
installation
RELEASE RATE PER MANNED INSTALLATION YEAR
OPERATOR
2000 / 2001
2001 / 2002
2002 / 2003
2003 / 2004
A
2.50
1.25
0.50
0.00
B
2.50
1.00
0.50
1.00
C
2.33
3.00
2.33
1.66
D
2.25
0.75
1.00
1.25
E
2.00
2.00
2.00
1.00
F
2.00
2.00
1.00
1.00
G
2.00
1.50
1.00
1.00
H
1.57
1.71
0.71
1.14
I
1.52
1.23
0.55
1.00
J
1.33
0.33
0.00
0.33
K
1.00
0.00
1.5
1.00
L
1.00
0.00
2.00
1.00
N
1.00
1.00
2.00
2.66
P
1.00
0.83
1.00
0.33
Q
0.82
0.73
0.31
0.94
T
0.43
0.11
0.44
0.55
Î Notes
1. Manned production installations only (i.e. excludes NUI’s)
2. All companies retain the same operator identification letter as per OTO 2001 055 except:
(i) Merged companies (i.e. Chevron Texaco, Conoco Phillips) retain identity of first named
company
(ii) Exxon Mobil retains Mobil identity
(iii) Shell retains Shell identity but also includes Enterprise data
Page 18 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
Table 5 – Installations with 3 or more major and significant hydrocarbon
release in the reference period
Year 2000 / 2001
Installation
Year 2003 / 2004
No of Releases
Installation
No of Releases
Brent A
9
Ravenspurn N
4
Alba
5
N. Cormorant
4
Curlew
5
Cormorant A
4
Triton
4
Brae B
4
Rough 47/3B
4
Thistle
4
Murchison
4
Judy
4
Anasuria
4
Gryphon
4
Dunbar
4
Inde 49/23
3
AH001
3
Dunlin
3
N. W. Hutton
3
Brae A
3
Clipper
3
Janice
3
Tern
3
Tartan
3
Í FOI exemption s.43 commercial interests
Page 19 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
Table 6 – Release analysis taxonomy
OPERATING
MODE*
RELEASE SITE
(1)
1. Start-up /
reinstatement
2. Normal
Production
3. Maintenance
4. Shut down /
shutting down
5. Construction
6. Well operations
/ drilling
7. Testing /
sampling
8. Pigging
1. Pipe flange
2. Pipe Weld
3. Pipe body
4. Pipe open end
5. Valve stem
6. Valve body
7. Valve flange
8. Valve open end
9. Vessel body
10. Vessel flange
11. Vessel open
end
12. Small bore
piping
13. Small bore
connection
14. Instrument
connection
15. Pump /
compressor flange
16. Pump /
compressor seal
17. Hose body
18. Swivel stack
19. Other
equipment seal
20. Heat exchanger
21. Turbine
22. Sighting glass
* For the system
where the release
occurred
RELEASE
SITE
(2)
1. Crack
2. Split
3. Hole
4. Pinhole
5. Temporary
repair
6. Grease
nipple
RELEASE
MECHANISM
IMMEDIATE
CAUSES
UNDERLYIKNG
CAUSES
1. Internal explosion
2. Overpressurisation
3. Under –
pressurisation
4. Open pathway
5. Degraded
containment
envelope
1. Corrosion /
internal
2. Corrosion /
external
3. Erosion
4. Fatigue / vibration
5. Incorrect
installation
6. Operator error
7. Degradation of
material properties
8. Procedural
violation
9. Inadequate
isolation
10. Blockage
11. Inadequate
procedures
12. Defective
equipment
13. Impact /
excessive
movement
1. Inadequate
compliance monitoring
2. Inadequate risk
assessment
3. Inadequate design
4. Inadequate
procedures
5. Inadequate
competency
6. Inadequate
supervision
7. Incorrect material
specification / usage
8. Inadequate task
specification
9. Excessive workload
10. Outdated
information / data
11. Incorrect
installation
12. Inadequate
maintenance
13. Inadequate
communication
14. Inadequate
inspection / condition
monitoring
Page 20 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
FAILED
SAFEGUARDIN
G SYSTEM
1. Locked valve
2. Permit to work
3. Isolation
4. Change control
5. Procedural
review
6. Design review
(incl. HAZOP)
7. Competency
assurance
8. Inspection /
condition
monitoring
9. Corrosion /
erosion monitoring
10. Construction /
commissioning
review
11. Operational
review (older
installations)
POTENTIAL
NEW /
ADDITIONAL
SAFEGUAR
DS
1. UKOOA / IP
small-bore
piping guide
2. Flange
verification
scheme
3. Regular
drawing
upgrades
4. HAZOP
Fig 1 – Minor liquid releases – size distribution
Page 21 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
Fig 2 – Significant liquid releases – size distribution
Page 22 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
Fig 3 - All releases by operating mode
Fig 3 All Releases by Operating Mode
Normal Production
Start Up / Re-instatement
Maintenance
Well Operation / Drilling
Abnormal Production
Shutdown / Shutting Down
Pigging
2000/1
Testing / Sampling
2003/4
Construction
0
10
20
30
40
50
60
Percentage of Releases
Fig 4 – All releases by hydrocarbon type
Fig 4 All Releases by Hydrocarbon Type
Helifuel
Lube Oil
2003/2004
Tw o-Phase
2000/2001
Diesel
Gas
0
10
20
30
40
Percentage of Releases
Page 23 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
50
60
Fig 5 – All releases by release site
Fig 5 All Releases by Release Site
Pipe Open End
Pipe Body
Pipe Flange
Pipe Weld
Small Bore Piping
Small Bore Connection
Instrument Connection
Valve Body
Valve Stem
Valve Open End
Valve Flange
Vessel Body
Vessel Flange
Vessel Open End
Pump/Compressor Seal
Pump/Compressor Flange
Hose Body
Other Equipment Seal
Swivel Seal
Temporary Repair
2003/4
2000/1
0
2
4
6
8
10
12
Percentage of Releases
Page 24 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
14
16
Fig 6 – Immediate causes – all releases
Fig 6 Immediate Causes - All Releases
Internal Corrosion
External Corrosion
Inadequate Procedures
Degradation of Properties
Errosion
Fatigue / Vibration
Inadequate Equipment
Inadequate Isolation
Inadequate Installation
Line Blockage
Operator Error
Procedural Violation
2000/1
Inadequate Communication
2003/4
Impact / Excessive Movement
0
5
10
15
20
Percentage of Total Incidents
Page 25 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
25
30
Fig 7 – Underlying causes – all releases
Fig 7 Underlying Causes - All Releases
Excessive Workload
Inadequate Communication
Inadequate Competency
Inadequate Compliance Monitoring
Inadequate Design
Inadequate Inspection / Condition Monitoring
Inadequate Installation
Inadequate Procedures
Inadequate Risk Assessment
Inadequate Supervison
Inadequate Task Specification
Incorrect Material Specification
Incorrect Material Usage
Outdated Information
Inadequate Maintenance
0
5
10
15
20
25
30
2000/1
2003/4
Percentage of Total Incidents
Page 26 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
Annex 1 - Summary of 2003/4 Major Releases
There were 5 major releases in 2003/4, with a size range of between 350kg and 2640kg of
hydrocarbon. Two were on the same installation, the other three were on different
installations with different operators. All occurred on manned production installations.
Four were gas releases and one a two-phase release, indicating that the biggest releases
were also of the most dangerous type, in terms of their ability to form flammable vapour
clouds. The immediate causes of the five releases were blockage, fatigue / vibration,
erosion, inadequate inspection / condition monitoring and degraded material properties
respectively. Outline summaries for each incident are as follows:
1.
350kg of gas escaped over a 2½ hour period from a fractured section of small bore
pipework. The section of pipework involved was not adequately supported and was
subject to vibration. Over a period of time, the vibration caused the pipework to fracture.
The incident was exacerbated by the correct emergency response procedures not being
followed.
2.
Loss of liquid level in a production separator led to a gas blow-by condition allowing
gas to flow via the closed drain caisson into the LP vent system. Partial obstruction of the
flame arrestor in the LP vent stack due to a combination of internal deposits and a
covering of dead birds, resulted in a restriction to gas flow and increased back-pressure in
the vent header. The rise in pressure led to glycol being expelled from a glycol sump tank
connected to the vent header. This led to glycol being spilled into the open drains system
and the resulting loss of level in the sump tank allowed gas from the vent header to flow
directly to atmosphere via the tank’s overflow line. In all an estimated 1000kg of gas was
released.
3.
A door seal on the zinc oxide filter failed whilst on trial resulting in release of gas
into the gas treatment module. The blow down valve covering the part of the system
which included the filter failed to open. This led to the size of the release being much
larger than should have been the case. An estimated total of 2540kg of gas was released.
4.
An unapproved temporary pipework repair failed allowing release of hydrocarbon.
During the subsequent surface process blowdown, a series of valve failures and
malfunctions resulted in the flow of process hydrocarbon fluids under pressure into the
location of the failed repair. This resulted in an estimated overall release of 2500kg of
hydrocarbon.
5.
A 2600kg two-phase release occurred from the outlet pipework of a gas test
separator. The pipework failure resulted from rapid erosion due to gas blow-by following a
failure to remove an inhibit on a low level trip. The gas had entrained propane, which had
accumulated in the base of the separator following its use as part of a perforation and
clean up campaign associated with a ‘frac’ job on one of the wells. The potential
consequences of the release were increased by the lack of a non-return valve in the line
which allowed significant quantities of condensate to flow back to the release site from
vessels higher in the system.
Page 27 of 27
Summary Report on the OSD Hydrocarbon Release Reduction Campaign
Mar 05
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