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Guidelines for
Annual DP Trials for DP
Mobile Offshore Drilling Units
www.imca-int.comIMCA M 191
February 2008
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ABThe International Marine Contractors Association(IMCA) is the
international trade association
representing offshore, marine and underwater
engineering companies.
IMCA promotes improvements in quality, health, safety,
environmental and technical standards through the publicationof
information notes, codes of practice and by other
appropriate means.
Members are self-regulating through the adoption of IMCA
guidelines as appropriate. They commit to act as
responsiblemembers by following relevant guidelines and being
willing to be
audited against compliance with them by their clients.
There are two core activities that relate to all members:
Safety, Environment & Legislation
Training, Certification & Personnel Competence
The Association is organised through four distinct
divisions,each covering a specific area of members interests:
Diving,
Marine, Offshore Survey, Remote Systems & ROV.
There are also four regional sections which facilitate work
on
issues affecting members in their local geographic area
Americas Deepwater, Asia-Pacific, Europe & Africa and
Middle
East & India.
IMCA M 191
This guidance was produced for IMCA under the direction of
its
Marine Division Management Committee.
www.imca-int.com/marine
The information contained herein is given for guidance only and
endeavours to
reflect best industry practice. For the avoidance of doubt no
legal liability shall
attach to any guidance and/or recommendation and/or statement
herein contained.
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Guidelines for Annual DP Trials for
DP Mobile Offshore Drilling Units
IMCA M 191 February 2008
1 Introduction
...........................................................................................................
1
1.1 Scope
....................................................................................................................................................................1
1.2 Background
.........................................................................................................................................................
1
2
Objectives...............................................................................................................
2
2.1 Primary Objectives
............................................................................................................................................
2
2.2 Secondary Objectives
.......................................................................................................................................
2
2.3 Additional
Objectives........................................................................................................................................2
3
Other Guidelines
...................................................................................................
3
4 DP Trials for
MODUs............................................................................................
4
4.1 Annual Trials Programme
................................................................................................................................
4
4.2 Arrangements for Annual Trials
Programme...............................................................................................
5
4.3 Annual Verification
............................................................................................................................................
5
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IMCA M 191 1
1
Introduction
1.1 Scope
These guidelines provide advice on undertaking the annual
dynamic positioning (DP) trials for DP
mobile offshore drilling units (MODUs) on a continual basis
throughout the year.
The purpose of the trial programme is to improve safety and
performance by reducing risk. These
guidelines propose a method of achieving these goals by
carefully managed testing of all important
systems and components of a DP system to ensure that the DP
system is maintained in good working
order. Particular focus is placed on verifying the conditions
from the failure modes and effects analysis
(FMEA) that are difficult or impossible to verify by any other
method. The trial programme may be
conducted on an incremental basis throughout the year as
opportunities arise but needs to be
completed within a twelve month period.
The guidelines are designed to provide a common approach for DP
MODU annual trials.
1.2 Background
In the 1980s DP systems onboard vessels were tested many times
during a year and the time required
for the frequent repetitious testing events was costly and
inconvenient for both vessel owners andtheir clients. In addition,
the frequent testing raised the risk of equipment damage.
In 1991 vessel owner representatives met with oil company and
government representatives to
discuss and rationalise the auditing and testing of dynamically
positioned vessels. This resulted in the
DPVOA guideline 112 UKOOA Part 2 which was published in 19921.
In 1993 the rationalisation
process continued and was enhanced with the production of
International Maritime Organization
(IMO) Maritime Safety Committee (MSC) circular 645 which was
adopted in 1994. This IMO circularrequires annual testing of all
important systems and components of a DP system to ensure that it
is
maintained in good working order.
The use of the traditional annual DP trial, where all of the DP
tests are carried out at a specific time
once a year, has not been widely accepted and taken up for DP
MODUs because their continuouswork programmes do not usually
provide suitable non-operational periods that can be used for
such
an approach. Therefore, these guidelines have been produced
setting out a reasonable way to
perform the trials programme incrementally throughout the year
as opportunities arise, while ensuring
that the total scope of the trials programme is accomplished
within a twelve month period.
1 DPVOA guidance note 112 UKOOA Part 2 Guidelines for auditing
vessels with dynamic positioning systemsis to be superseded by
guidance document IMCA M 190 Annual trials for DP vessels,
expected to be published in early 2008.
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2
Objectives
2.1 Primary Objectives
The primary objective of the annual trials programme is to
improve the safety of DP MODU
operations by:
encouraging MODU vessel owners to carry out detailed, auditable
tests as part of an annual trials
programme;
verifying that the DP system is in good working order and that
the FMEA remains valid.
2.2 Secondary Objectives
The secondary objectives of the annual trials programme are:
to provide a common standard approach for the auditing and
accepting of DP vessels by client
companies that adequately discharges their duty of care to the
satisfaction of their regulatorybodies;
to make the DP testing and acceptance process more efficient and
thus save the industry time andunnecessary cost.
2.3 Additional Objectives
Additional objectives of the annual trials programme are:
to give failure response training and experience to DP
personnel;
to document the trials results;
to demonstrate good management of change.
2 IMCA M 191
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IMCA M 191 3
3
Other Guidelines
These guidelines do not replace IMCA M 1902which sets out
guidelines for undertaking the full annual trial
programme at a specific time once a year for other types of DP
vessels, as described in IMCA M 103 Guidelines for the design and
operation of dynamically positioned vessels. Such a programme is
applicable to other
types of DP vessels.
Guidance document IMCA M 182 International guidelines for the
safe operation of dynamically positioned offshoresupply vessels
sets out specific arrangements for annual DP trials for offshore
supply vessels.
2 DPVOA guidance note 112 UKOOA Part 2 Guidelines for auditing
vessels with dynamic positioning systemsis to be superseded by
guidance document IMCA M 190 Annual trials for DP vessels,
expected to be published in early 2008.
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IMCA M 191 5
The vessel master/offshore installation manager (OIM) and any
other witnesses to the tests making up
the annual trials programme need to be familiar with:
the FMEA report;
the last annual trials programme report;
the proposed content of the forthcoming annual trials
programme;
recent developments in the industry with respect to DP
incidents; and
system modifications since last annual trials.
The vessel master/OIM may consider the planned maintenance
status report available prior to any
tests being performed so that this can be taken into account
during the tests. The vessel master/OIM
should also have access to any vendor visit reports so that
tests may be adjusted to prove that
problems experienced relevant to DP were corrected.
For each test making up the annual trials programme, the
following should be recorded:
1 Purpose (what is planned to be demonstrated);
2 Method (how it is to be carried out);
3 Results expected locally and for DP;
4
Results found;5 Comments;
6 Date and signature of vessel master/OIM witnessing the
test.
Completion of each test should be recorded in a table/log
showing the dates when each test was
conducted.
4.2 Arrangements for Annual Trials Programme
These guidelines set out the requirement for DP MODUs to
undertake a DP trials programme on an
annual basis.
Due to the nature of DP drilling work, with a DP MODU often
connected to an exploration orproduction well for extended periods
of time, it is not always possible to set aside sufficient time
during a year to undertake the full annual trials programme in
one go. Therefore, provided that the
total scope of the tests which make up the annual trials
programme is covered, the tests can be
undertaken incrementally throughout the year as the
opportunities arise.
If the opportunity to undertake the full annual trials programme
at one time presents itself, for
example after dry-dock, this is preferred because of the ability
to verify integrity of the DP systems
after maintenance, repair or modification.
If the full annual trials programme is required prior to a
contract, then the complete programme
should be carried out. However, the incremental tests making up
the annual trials programme carried
out over the preceding year may be able to satisfy this
requirement.
4.3 Annual Verification
Each year an annual verification exercise should be undertaken
by the vessel owners fleet DP
superintendent/in-house independent specialist or other senior
corporate official to review and accept
that the various tests identified in the annual trials programme
have been completed and that an
appropriate report is provided for each test. It may be
appropriate for the vessel owner to mobilise a
competent independent third party consultant to undertake this
verification and to inform clients, for
whom the MODU is expected to work during the following year, so
that they may review the annual
trials programme results if they so wish.
Tests relating to any modifications made to the vessel during
the year should be included in the annual
verification and should be added to the annual trials programme
for future years.
The execution of the annual verification should be decided to
best fit into planned operations but
should be carried out within three months of completion of all
the tests identified in the annual trials
programme.
