Description
Our paper about rapid a new approach for improved regularity and decreased maintenance costs.
ERTC Reliability & Asset Management Conference & Workshop
RAPID: A New Approach for Improved
Regularity and Decreased Maintenance Costs
Dr.Ing. Trond M. Andersen Statoil
Arkitekt Ebbels v. 10, Posttuktak, Rotvoll, Trondheim, , Norway, N-7005
MSc Lars Thuestad Statoil
MSc Tom A Thorstensen Marintek
Norway is the world’s 3rd largest trader of crude oil, and a significant supplier of gas to the
European market. Statoil is a Norwegian based oil company, with 17.000 employees, and
with a number of offshore production plants, pipelines and land based facilities. As part of an
improvement campaign with focus on increased production and reduced maintenance and
operational costs, Statoil is working with a new initiative related to turnaround strategies and
execution of maintenance that requires shutdown. This campaign is called RAPID, which
stands for “Remove Activities, Prolong Intervals and Decrease durations”. The initiative was
due to the fact that turnarounds are the largest single contributor to reduced production in
Statoil. Turnarounds with production shutdown are conducted on a regular basis, with a
typical duration of 15 days and with a 1-3 yrs. frequency for offshore facilities and 4-8 yrs.
for land based facilities. It is a long-term objective to reduced lost production due to
turnarounds by increased use of condition monitoring, new procedures for hot work, safety
integrity verification, opportunity maintenance and improved planning. This paper describes
the on-going campaign and its applied methods. The work for 2003 is focused on two main
products: a new turnaround strategy for a pilot offshore installation (Heidrun) and a general
Company guideline for turnarounds.
ERTC Reliability 2003, Barcelona, Spain Page 1 Statoil
ACRONYMS AND DEFINITIONS
Name Definition
CBM Condition Based Maintenance
HSE Health, Safety and Environment
LNG Liquefied Natural Gas
NCS Norwegian Continental Shelf
Opportunity Maintenance Execution of selected planned and corrective maintenance at
opportunities generated by unscheduled production
shutdowns
RAPID Remove Activities, Prolong intervals, and Increase Durations
Statoil home page http://www.statoil.com
SAP Trademark. World's largest inter-enterprise software
company. Maintenance administration tool used by Statoil.
Turnaround Execution of large amount of planned maintenance activities
during limited time related to work that requires full or partly
production stop. Originally related to revision of pressurized
equipment or other critical equipment with special
governmental concern.
ERTC Reliability 2003, Barcelona, Spain Page 2 Statoil
INTRODUCTION
General
Statoil is a medium size oil company, with approximately 17.000 employees worldwide. The
main activities are in the North Sea region outside the coast of Norway. The company has
also increased its activities in other regions such as Iran, Caspian, West Africa and Venezuela.
Today Statoil is the world’s third largest trader of crude, and large amounts of gas are
exported to the European Continent. The company operates several onshore and offshore
facilities, both “old” installations (from late 1970s) and new installations, recently put into
operation. Examples of new projects are Kvitebjørn (offshore production plant), Kristin
(offshore production plant) and Snøhvit (land based LNG plant with subsea installations). In
2002, the production was in average 1074 boe/day, whereas 92% of this from the NCS
(Norwegian Continental Shelf).
Statoil is daily facing challenges related to asset management, e.g. maintenance of tail end
production facilities (declined fields), maintenance of subsea production equipment, and
operation and maintenance of facilities abroad. A major task is to change the work culture and
work processes from being repair oriented, with focus on repairing breakdowns, to being
proactive, maintaining critical equipment before failures occur. Typical focus areas are
turnaround strategy optimization, remote operation of facilities, improved maintenance
management strategies, increased use of condition monitoring and use of mobile ICT
(Information Communication Technology). Statoil is today facing competition from new
companies willing to take over the operation and maintenance of small/declined fields in the
North Sea. In order to compete with these new actors, Statoil have to look at ways of reducing
the maintenance and operational costs. One important parameter to be a successful operator is
to have sufficient control over the technical condition of the process plant and the equipment.
Having control over the technical condition of the plant and equipment, being able to predict
failures before they occur and estimate the residual life of critical equipment, are basic
elements in a proactive maintenance philosophy. This, combined with continuous work on
removing root-cause of failures, results in improved planning, increased production, reduced
costs and reduced risk of hazards related to personnel and environment.
Statoil has ongoing activities and utilize extensive effort to develop methods and tools that
define and monitor the technical condition both on the lowest level as well as on the system
and plant level /1/. The activities do also include development and utilization of existing and
ERTC Reliability 2003, Barcelona, Spain Page 3 Statoil
new condition monitoring techniques. These activities is seen as very important to be able to
change the regime from fixed turnarounds to an on-condition and opportunity based
philosophy.
Turnarounds in Statoil
In Statoil, 20 offshore platforms and 5 on-shore plants (crude oil and gas treatment plants and
refineries) are subjected to turnarounds on a regular basis. The facilities are all linked together
in a complex production infrastructure consisting of production pipes and shuttle tankers. This
infrastructure ensures that oil and gas from the wells finally reaches the marked.
There are differences in the offshore and onshore turnarounds practice. Onshore, the
turnaround frequency is typical 5 yrs., the duration is typical 4 weeks and the amount of work
approx. 150 000 hours. Offshore, the frequency is typical 1-2 yrs., the duration is typical 2
weeks and the amount of work between 14 000 - 90 000 hours. The turnaround-planning
organisation varies from being a fixed organisation to an “ad hoc” organisation for each
turnaround. The work is performed by contractors, offshore with one single contractor and
onshore with a selection of minor contractors for separate work packages. The logistics
support challenge is quite different between offshore and onshore turnarounds. Offshore, the
weather dependency (restricted to late spring, summer or early autumn) and limitations
related to transport of spares (high costs due to use of supply ship, helicopter), personnel and
materials requires much more planning effort and limits the freedom of work execution. The
transportation time is long, and it is extremely costly to require a helicopter for transport
outside the scheduled routes. Also, limited amount of beds, limited space for storage and
limited workspace makes the offshore turnaround planning more complicated compared to
onshore. There are also differences in the rules and regulations for execution of maintenance,
which requires for differences in the turnaround practices. Onshore, the use of incentive
contracts has been used as a mean to increase the quality of work, that is, to keep the budget
and time and the HSE objectives. This has not been the practice offshore, so far. In general,
the onshore facilities have been challenging the turnaround strategy to a larger extent
compared to offshore because the onshore plant normally works within lower margins. As
several of the oil fields are maturing (tail end production), the pressure to prolong economic
life is forcing an increased focus on cost reduction and minimum lost production. In this new
regime, the offshore installations are facing the same “competitive” environment as many of
ERTC Reliability 2003, Barcelona, Spain Page 4 Statoil
the onshore plants have been used to since start up. Several external companies are offering
“tail end production” as a special service, and are challenging the way Statoil are performing
tail-end production. In the British sector, outsourcing of tail end production is common,
whereas Statoil has a strategy to do this with internal resources.
Limitations in today’s turnaround strategy: A hypothesis
The background for the RAPID project is the hypothesis that the turnaround practice today
can be improved, especially for the offshore installations. This is based on the following
observations:
- A turnaround is seen upon as a regular event, in which other and not critical jobs
usually have been added. The turnaround frequency and duration is typically defined
during the project period, and is not necessarily challenged later.
- A turnaround is seen upon as a cost-effective and focused activity, with highly
motivated personnel in all phases. This might be based on characteristics of the human
being, enjoying focused improvements with common objectives; teamwork and “lots
of action” more than continuous improvement as part of daily work. However, recent
studies have revealed that the average costs often increases for jobs performed during
a turnaround compared to jobs executed as a “normal” maintenance job.
- There is a tendency that modification projects use the regular turnaround as a “free
ride”, that is, since the plant already is shut down, the project don’t have to account for
the lost production.
- The job candidates for a turnaround are not challenged hard enough, compared to the
consequence these jobs have on lost production. The focus is normally higher for the
planning and execution phase compared to the job selection and scope of work. A
typical offshore plant production value is 3 - 7 mil. $/day, which is a good reason to
invest in knowledge, methods and technology in order to reduced the amount of
shutdown work.
- The successful turnaround is related to good HSE performance (no injuries,
environmental spills, job satisfaction etc.) and to keeping the time and budget. Hence,
the evaluation of a turnaround is project execution focused, and does not sufficiently
evaluate whether the turnaround frequency and scope of work was optimal.
- There is limited overall optimisation for all installations as seen as a “super production
structure”. That is, each plant defines its own turnaround frequency, requested time for
ERTC Reliability 2003, Barcelona, Spain Page 5 Statoil
execution and scope of work. There is limited coordination between the shutdowns,
only ensuring that the production commitments to the market are fulfilled and that
sufficient work craft is available.
- To prolong the turnaround frequency there is a need for improved knowledge of the
technical condition to minimize the probability of unforeseen shutdown between two
turnarounds by utilizing opportunities caused by unforeseen shutdowns.
Optimisation of turnarounds
Optimisation of turnarounds is a challenge in view of the large number of tasks to perform,
dependencies on the facility itself as well as dependency between other facilities. The
methods, tools and procedures that found basis for the latest turnarounds have mainly been
developed and optimised based on feedback from previous turnarounds. Different practices
have developed for each facility both due to the age (and generation) of the facilities but also
due to minor exchange of experience between the different organisations responsible for each
facility. Pre-studies have revealed a great potential for improvements only by performing a
more structured exchange of experience, methods, procedures and tools. Examples of such a
case is the need of revising procedures used in the shutdown phase before hot work is
permitted. Some facilities do already have a nearby optimal procedure while other struggle
with procedures that only have been through minor changes since the production start-up.
However, it does exist an overall optimisation challenge related to execution of turnarounds in
Statoil that will require a considerable effort to accomplish. In this context we have limited
the presentation of the topic, and do only include a list of the main observations regarding
input to an overall optimisation model. The “big picture” includes:
- 20 offshore installations and 5 land based plants
- Gas and oil pipeline dependency
- Sale obligations (most sale during winter, highest price)
- Available workforce and skill (restricted amount of qualified workers)
- Logistics support (economic dependency, limited resources)
- Weather conditions (turnarounds not feasible during winter time)
- Type of jobs:
o “Normal” maintenance (planned preventive, planned corrective, unforeseen
corrective) that do not influence the production
ERTC Reliability 2003, Barcelona, Spain Page 6 Statoil
o Maintenance that requires partly or full production stops (planned preventive,
unforeseen corrective)
- Vulnerability for extensive production losses because of a low degree of redundancy,
especially on the newest facilities.
The overall optimisation problem can be solved by use of mathematics. If doing so the
problem formulation should address aspects as:
- Global optimisation vs. local optimisation
- Objective function: Maximum profitable production of oil, production of gas
according to obligations
- Penalty: failures and breakdowns that results in increased costs and lost production
- Constraints:
o Production [gas: obligation, oil: maximum]
o Personnel [limited]
o Weather
o Logistics support [economic dependency, limited resources]
At present we do only control the local variables and have therefore not elaborated more on
the global picture. This will however be an area of interest in the future.
TURNAROUND IMPROVEMENT PROJECT
Statoil is working with several initiatives related to turnaround strategies and execution of
maintenance that requires shutdown. One campaign is called RAPID, which stands for
“Remove Activities, Prolong Intervals and Decrease durations”. The objective is to reduce
lost production due to turnarounds by increased use of condition monitoring, new procedures
for hot work, safety integrity verification, opportunity maintenance and improved planning.
The work for 2003 is focused on two main products: a new maintenance strategy for a pilot
offshore installation (Heidrun) and a best practice guideline for turnarounds.
The Heidrun TLP (Tension Leg Platform) is situated 80 km North-West of Trondheim in mid
Norway. It produces crude oil to shuttle tankers, gas and condensate to pipeline. Gas to the
methanol plant at Tjeldbergodden and condensate to the Åsgard field. The turnaround interval
for Heidrun has been two years, where the latest turnaround was in 2002 (14 days, 24 000
ERTC Reliability 2003, Barcelona, Spain Page 7 Statoil
hours). The improvement projects has defined a short term objective and a long term
objective:
1. Next turnaround in 2004 with 7 days duration (reducing from 14 to 7)
2. Remove the need for large turnarounds in the future. For production critical jobs this
means: reducing the need for these jobs, increase the interval between execution of
these jobs and decrease the shutdown duration when executing these jobs.
In this context, the shut down duration is defined as the time from start of production shut
down until the first well starts to deliver hydrocarbons to the infrastructure.
A secondary objective is to improve the planning and execution of production critical jobs in
general, which has been the “normal” focus of turnaround improvements.
In order to obtain these objectives, the following elements have been identified as important:
- Utilisation of opportunities (unscheduled production shutdowns)
- Improved use of condition monitoring
o Use of existing methods
o New methods
- New methods and procedures for welding during operation
- New method for work challenge
- Improved planning
Pilot project: RAPID
As previously explained, RAPID is an acronym for “Remove Activities, Prolong Intervals
and Decreases duration”. In the following, the RAPID project is described in more detail.
Though the RAPID project focuses the effort on only one facility, the observations and
methods for improvements are expected to be useful to other Statoil facilities. The future
work does also include an approach to generalize the results from Heidrun and to produce
content to a “best practice document” within Statoil.
Remove Activities:
As seen in previous chapter there is magnitude of decade between the amounts of man-hours
carried out during a turnover onshore compared to offshore. The main reason for this is
limitations in berthing capacity offshore. Since we have this upper limit of daily man-hours
ERTC Reliability 2003, Barcelona, Spain Page 8 Statoil
capacity, there is a danger of prolonging the shutdown and consequently increase the
production losses. This, combined with the fact that turnaround work costs 30% more is a
driving force to remove activities from the turnaround scope of work. Our approach is first to
challenge each job candidate before entered into the turnaround work list in SAP by
investigating all means to perform the job during full production. Secondly, the work lists are
challenged, both regarding interval and duration. Since the organisation is “used to” having a
turnaround on a regular basis, it is quite a challenge to get the organisation to change its
behaviour. A key word in the change process is “opportunity maintenance”. As most of our
production units have low degree of redundancy or no redundancy at all, one has to use any
production trip or stop to perform maintenance. There must therefore exist pre-planned jobs
for any length of stop in production. It may also be situations where one will negotiate for
longer stops as an extension to a process trip to perform vital maintenance work. This requires
a close integration of the Operation and the Maintenance departments and a constant
cost/benefit optimisation. Since typical turnaround work includes welding and other types of
“Hot work” (Hot work during operation has up to now been banned in Statoil). To be able to
perform hot work in a safe manner, special precautions have to be made. This includes
welding habitats with overpressure in combination with automatic power cut on welding
device.
By excellent planning work and implementation of most recent welding safety precautions it
is expected that many typical turnaround activities can be performed during normal operation.
Prolong intervals
The second focus area in the RAPID model is to prolong the intervals between major
activities. In turnaround terms this is mainly inspection of pressure vessels and drums for
corrosion, and overhaul of large rotating equipments as turbines, pumps and compressors.
From experience we have learned that these inspections not seldom turn out with no findings,
as they hopefully should. If we had known this in advance, the whole activity could be
postponed to a time where we expect to find damage. This means that many labour and time
intensive activities could be saved. By applying existing and develop new condition
monitoring methods, vital process equipment is only opened and inspected when needed and
this will affect the time between turnarounds considerably.
For rotating machinery as pumps, turbines and compressors a variety of methods, techniques
and equipment is available and in use on our production units.
ERTC Reliability 2003, Barcelona, Spain Page 9 Statoil
The largest challenges are related to the areas of corrosion inspection and performance
verification of separators, pressure vessels and scrubbers. Since these equipments often are
insulated, they are hard to inspect from the outside during operation. Development of new
technology may be required.
Decrease duration
The third element in our concept is to decrease the duration of the turnaround. Since the main
objectives of the two first phases is to avoid work to enter the turnaround work scope the
main objective of this phase is to reduce the work further, in addition to plan and structure the
work in a manner that minimise downtime and production losses. Key elements here are a
strong turnaround planning organisation with authority to prioritise work to be performed, and
to exclude work that not have to be done within the time frame of the turnaround. Further the
turnaround organisation should have excellent planning skills and capabilities.
Example:
In the Heidrun pilot project, separator maintenance has been identified as the most critical
activity, both regarding duration and costs. Based on this fact, a considerable amount of work
has been performed, trying to challenge the separator work. In this case, a supplier is
responsible for performing the work, and several meetings have been performed together with
the supplier in order to identify improvement activities. The separator maintenance work was
divided into sub-tasks, where each sub tasks was challenged regarding time and costs. The
results for this work have been a long list of improvement activities, reducing the original
execution time estimate with 23 hours, from 117 hours to 94 hours.
The experience from the RAPID project so far is that considerable savings can be obtained
just by having a sufficient focus and a structured way of working.
ACADEMIC WORK
In general, turnaround activities are part of asset management and maintenance optimisation
in general. The fundamental system and process characteristics are defined in the design
phase of a facility, but there is always room for design improvement also in the operational
phase, if proven economical beneficial. Each turnaround activity is identified based on its
influence on production or other risk aspect, and is modelled as an activity with a duration
ERTC Reliability 2003, Barcelona, Spain Page 10 Statoil
and an associated cost. Each activity has an influence on production with three specific
phases: shut down period, execution period and start-up period. Obviously, the main reason
for grouping jobs in turnarounds is to minimize losses related to shutdown and start-ups. The
interval between turnaround activities is a risk optimisation problem (or a pure cost
optimisation problem if all risk elements can be measured in dollars). A long interval has high
risk for critical events whereas a short interval is costly due to lost production and the activity
costs. Activities governed by rules and regulations are not candidates for interval
optimisation. Based on the risk aspect, downtime costs and other relevant constraints, it is
possible to establish simulation models that calculates the costs of different turnaround
strategies, for example, the cost difference between having a large turnaround each year
compared to several small stops based on opportunities. There has been performed some
academic studies in the RAPID project. The result of this work will be published later.
In the future, more work will be performed related to mathematical optimisation of
turnaround strategies in addition to the more continuous improvement work. Students from
NTNU (Norwegian University of Science and Technology) play a vital role in this work
together with researchers from SINTEF/ MARINTEK. Also, it is planned to look further into
“global” optimisation of turnarounds in Statoil, taking all offshore and onshore facilities into
account, with their production infrastructure and various types of local and global constraints.
The main objective is to maximise the production, minimize the costs and to be a reliable
supplier of hydrocarbons to the market.
CONCLUSION
Our initial studies have shown that there are signification potentials of savings in optimising
turnarounds for our production units. The potentials are in magnitude of several million
dollars. The Heidrun pilot project has so far demonstrated that by ensuring high focus on
turnarounds and work systematic together with experienced personnel, significant
improvements can be obtain. In addition, more “academic” tools and methods can be
developed and implemented to further obtain savings. These methods will be investigated
further in future work, and a “best practice” related to turnaround planning and management
will be established for Statoil in general. To materialise these savings more effort must be put
into condition monitoring. New monitoring technologies have to be developed and the
planning capability has to strengthen significantly. It is important that turnarounds are not
seen upon as a special area, divided from other maintenance activities, but as a subset of asset
ERTC Reliability 2003, Barcelona, Spain Page 11 Statoil
management, with high criticality, that is, impact on production, safety, environment and
costs. In theory, a good design is to minimize maintenance that influence the production, but
it will always be a trade off between investment costs and operational costs related to this.
References
/1/ T.M. Andersen, Thorstensen et.al.; Aging Management: Aggregated Monitoring of
Technical Condition for Aging Equipment, 10th International Conference and
Exhibition Process & Power Plant Reliability, Houston, 2001.
ERTC Reliability 2003, Barcelona, Spain Page 12 Statoil
doc_197758481.pdf
Our paper about rapid a new approach for improved regularity and decreased maintenance costs.
ERTC Reliability & Asset Management Conference & Workshop
RAPID: A New Approach for Improved
Regularity and Decreased Maintenance Costs
Dr.Ing. Trond M. Andersen Statoil
Arkitekt Ebbels v. 10, Posttuktak, Rotvoll, Trondheim, , Norway, N-7005
MSc Lars Thuestad Statoil
MSc Tom A Thorstensen Marintek
Norway is the world’s 3rd largest trader of crude oil, and a significant supplier of gas to the
European market. Statoil is a Norwegian based oil company, with 17.000 employees, and
with a number of offshore production plants, pipelines and land based facilities. As part of an
improvement campaign with focus on increased production and reduced maintenance and
operational costs, Statoil is working with a new initiative related to turnaround strategies and
execution of maintenance that requires shutdown. This campaign is called RAPID, which
stands for “Remove Activities, Prolong Intervals and Decrease durations”. The initiative was
due to the fact that turnarounds are the largest single contributor to reduced production in
Statoil. Turnarounds with production shutdown are conducted on a regular basis, with a
typical duration of 15 days and with a 1-3 yrs. frequency for offshore facilities and 4-8 yrs.
for land based facilities. It is a long-term objective to reduced lost production due to
turnarounds by increased use of condition monitoring, new procedures for hot work, safety
integrity verification, opportunity maintenance and improved planning. This paper describes
the on-going campaign and its applied methods. The work for 2003 is focused on two main
products: a new turnaround strategy for a pilot offshore installation (Heidrun) and a general
Company guideline for turnarounds.
ERTC Reliability 2003, Barcelona, Spain Page 1 Statoil
ACRONYMS AND DEFINITIONS
Name Definition
CBM Condition Based Maintenance
HSE Health, Safety and Environment
LNG Liquefied Natural Gas
NCS Norwegian Continental Shelf
Opportunity Maintenance Execution of selected planned and corrective maintenance at
opportunities generated by unscheduled production
shutdowns
RAPID Remove Activities, Prolong intervals, and Increase Durations
Statoil home page http://www.statoil.com
SAP Trademark. World's largest inter-enterprise software
company. Maintenance administration tool used by Statoil.
Turnaround Execution of large amount of planned maintenance activities
during limited time related to work that requires full or partly
production stop. Originally related to revision of pressurized
equipment or other critical equipment with special
governmental concern.
ERTC Reliability 2003, Barcelona, Spain Page 2 Statoil
INTRODUCTION
General
Statoil is a medium size oil company, with approximately 17.000 employees worldwide. The
main activities are in the North Sea region outside the coast of Norway. The company has
also increased its activities in other regions such as Iran, Caspian, West Africa and Venezuela.
Today Statoil is the world’s third largest trader of crude, and large amounts of gas are
exported to the European Continent. The company operates several onshore and offshore
facilities, both “old” installations (from late 1970s) and new installations, recently put into
operation. Examples of new projects are Kvitebjørn (offshore production plant), Kristin
(offshore production plant) and Snøhvit (land based LNG plant with subsea installations). In
2002, the production was in average 1074 boe/day, whereas 92% of this from the NCS
(Norwegian Continental Shelf).
Statoil is daily facing challenges related to asset management, e.g. maintenance of tail end
production facilities (declined fields), maintenance of subsea production equipment, and
operation and maintenance of facilities abroad. A major task is to change the work culture and
work processes from being repair oriented, with focus on repairing breakdowns, to being
proactive, maintaining critical equipment before failures occur. Typical focus areas are
turnaround strategy optimization, remote operation of facilities, improved maintenance
management strategies, increased use of condition monitoring and use of mobile ICT
(Information Communication Technology). Statoil is today facing competition from new
companies willing to take over the operation and maintenance of small/declined fields in the
North Sea. In order to compete with these new actors, Statoil have to look at ways of reducing
the maintenance and operational costs. One important parameter to be a successful operator is
to have sufficient control over the technical condition of the process plant and the equipment.
Having control over the technical condition of the plant and equipment, being able to predict
failures before they occur and estimate the residual life of critical equipment, are basic
elements in a proactive maintenance philosophy. This, combined with continuous work on
removing root-cause of failures, results in improved planning, increased production, reduced
costs and reduced risk of hazards related to personnel and environment.
Statoil has ongoing activities and utilize extensive effort to develop methods and tools that
define and monitor the technical condition both on the lowest level as well as on the system
and plant level /1/. The activities do also include development and utilization of existing and
ERTC Reliability 2003, Barcelona, Spain Page 3 Statoil
new condition monitoring techniques. These activities is seen as very important to be able to
change the regime from fixed turnarounds to an on-condition and opportunity based
philosophy.
Turnarounds in Statoil
In Statoil, 20 offshore platforms and 5 on-shore plants (crude oil and gas treatment plants and
refineries) are subjected to turnarounds on a regular basis. The facilities are all linked together
in a complex production infrastructure consisting of production pipes and shuttle tankers. This
infrastructure ensures that oil and gas from the wells finally reaches the marked.
There are differences in the offshore and onshore turnarounds practice. Onshore, the
turnaround frequency is typical 5 yrs., the duration is typical 4 weeks and the amount of work
approx. 150 000 hours. Offshore, the frequency is typical 1-2 yrs., the duration is typical 2
weeks and the amount of work between 14 000 - 90 000 hours. The turnaround-planning
organisation varies from being a fixed organisation to an “ad hoc” organisation for each
turnaround. The work is performed by contractors, offshore with one single contractor and
onshore with a selection of minor contractors for separate work packages. The logistics
support challenge is quite different between offshore and onshore turnarounds. Offshore, the
weather dependency (restricted to late spring, summer or early autumn) and limitations
related to transport of spares (high costs due to use of supply ship, helicopter), personnel and
materials requires much more planning effort and limits the freedom of work execution. The
transportation time is long, and it is extremely costly to require a helicopter for transport
outside the scheduled routes. Also, limited amount of beds, limited space for storage and
limited workspace makes the offshore turnaround planning more complicated compared to
onshore. There are also differences in the rules and regulations for execution of maintenance,
which requires for differences in the turnaround practices. Onshore, the use of incentive
contracts has been used as a mean to increase the quality of work, that is, to keep the budget
and time and the HSE objectives. This has not been the practice offshore, so far. In general,
the onshore facilities have been challenging the turnaround strategy to a larger extent
compared to offshore because the onshore plant normally works within lower margins. As
several of the oil fields are maturing (tail end production), the pressure to prolong economic
life is forcing an increased focus on cost reduction and minimum lost production. In this new
regime, the offshore installations are facing the same “competitive” environment as many of
ERTC Reliability 2003, Barcelona, Spain Page 4 Statoil
the onshore plants have been used to since start up. Several external companies are offering
“tail end production” as a special service, and are challenging the way Statoil are performing
tail-end production. In the British sector, outsourcing of tail end production is common,
whereas Statoil has a strategy to do this with internal resources.
Limitations in today’s turnaround strategy: A hypothesis
The background for the RAPID project is the hypothesis that the turnaround practice today
can be improved, especially for the offshore installations. This is based on the following
observations:
- A turnaround is seen upon as a regular event, in which other and not critical jobs
usually have been added. The turnaround frequency and duration is typically defined
during the project period, and is not necessarily challenged later.
- A turnaround is seen upon as a cost-effective and focused activity, with highly
motivated personnel in all phases. This might be based on characteristics of the human
being, enjoying focused improvements with common objectives; teamwork and “lots
of action” more than continuous improvement as part of daily work. However, recent
studies have revealed that the average costs often increases for jobs performed during
a turnaround compared to jobs executed as a “normal” maintenance job.
- There is a tendency that modification projects use the regular turnaround as a “free
ride”, that is, since the plant already is shut down, the project don’t have to account for
the lost production.
- The job candidates for a turnaround are not challenged hard enough, compared to the
consequence these jobs have on lost production. The focus is normally higher for the
planning and execution phase compared to the job selection and scope of work. A
typical offshore plant production value is 3 - 7 mil. $/day, which is a good reason to
invest in knowledge, methods and technology in order to reduced the amount of
shutdown work.
- The successful turnaround is related to good HSE performance (no injuries,
environmental spills, job satisfaction etc.) and to keeping the time and budget. Hence,
the evaluation of a turnaround is project execution focused, and does not sufficiently
evaluate whether the turnaround frequency and scope of work was optimal.
- There is limited overall optimisation for all installations as seen as a “super production
structure”. That is, each plant defines its own turnaround frequency, requested time for
ERTC Reliability 2003, Barcelona, Spain Page 5 Statoil
execution and scope of work. There is limited coordination between the shutdowns,
only ensuring that the production commitments to the market are fulfilled and that
sufficient work craft is available.
- To prolong the turnaround frequency there is a need for improved knowledge of the
technical condition to minimize the probability of unforeseen shutdown between two
turnarounds by utilizing opportunities caused by unforeseen shutdowns.
Optimisation of turnarounds
Optimisation of turnarounds is a challenge in view of the large number of tasks to perform,
dependencies on the facility itself as well as dependency between other facilities. The
methods, tools and procedures that found basis for the latest turnarounds have mainly been
developed and optimised based on feedback from previous turnarounds. Different practices
have developed for each facility both due to the age (and generation) of the facilities but also
due to minor exchange of experience between the different organisations responsible for each
facility. Pre-studies have revealed a great potential for improvements only by performing a
more structured exchange of experience, methods, procedures and tools. Examples of such a
case is the need of revising procedures used in the shutdown phase before hot work is
permitted. Some facilities do already have a nearby optimal procedure while other struggle
with procedures that only have been through minor changes since the production start-up.
However, it does exist an overall optimisation challenge related to execution of turnarounds in
Statoil that will require a considerable effort to accomplish. In this context we have limited
the presentation of the topic, and do only include a list of the main observations regarding
input to an overall optimisation model. The “big picture” includes:
- 20 offshore installations and 5 land based plants
- Gas and oil pipeline dependency
- Sale obligations (most sale during winter, highest price)
- Available workforce and skill (restricted amount of qualified workers)
- Logistics support (economic dependency, limited resources)
- Weather conditions (turnarounds not feasible during winter time)
- Type of jobs:
o “Normal” maintenance (planned preventive, planned corrective, unforeseen
corrective) that do not influence the production
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o Maintenance that requires partly or full production stops (planned preventive,
unforeseen corrective)
- Vulnerability for extensive production losses because of a low degree of redundancy,
especially on the newest facilities.
The overall optimisation problem can be solved by use of mathematics. If doing so the
problem formulation should address aspects as:
- Global optimisation vs. local optimisation
- Objective function: Maximum profitable production of oil, production of gas
according to obligations
- Penalty: failures and breakdowns that results in increased costs and lost production
- Constraints:
o Production [gas: obligation, oil: maximum]
o Personnel [limited]
o Weather
o Logistics support [economic dependency, limited resources]
At present we do only control the local variables and have therefore not elaborated more on
the global picture. This will however be an area of interest in the future.
TURNAROUND IMPROVEMENT PROJECT
Statoil is working with several initiatives related to turnaround strategies and execution of
maintenance that requires shutdown. One campaign is called RAPID, which stands for
“Remove Activities, Prolong Intervals and Decrease durations”. The objective is to reduce
lost production due to turnarounds by increased use of condition monitoring, new procedures
for hot work, safety integrity verification, opportunity maintenance and improved planning.
The work for 2003 is focused on two main products: a new maintenance strategy for a pilot
offshore installation (Heidrun) and a best practice guideline for turnarounds.
The Heidrun TLP (Tension Leg Platform) is situated 80 km North-West of Trondheim in mid
Norway. It produces crude oil to shuttle tankers, gas and condensate to pipeline. Gas to the
methanol plant at Tjeldbergodden and condensate to the Åsgard field. The turnaround interval
for Heidrun has been two years, where the latest turnaround was in 2002 (14 days, 24 000
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hours). The improvement projects has defined a short term objective and a long term
objective:
1. Next turnaround in 2004 with 7 days duration (reducing from 14 to 7)
2. Remove the need for large turnarounds in the future. For production critical jobs this
means: reducing the need for these jobs, increase the interval between execution of
these jobs and decrease the shutdown duration when executing these jobs.
In this context, the shut down duration is defined as the time from start of production shut
down until the first well starts to deliver hydrocarbons to the infrastructure.
A secondary objective is to improve the planning and execution of production critical jobs in
general, which has been the “normal” focus of turnaround improvements.
In order to obtain these objectives, the following elements have been identified as important:
- Utilisation of opportunities (unscheduled production shutdowns)
- Improved use of condition monitoring
o Use of existing methods
o New methods
- New methods and procedures for welding during operation
- New method for work challenge
- Improved planning
Pilot project: RAPID
As previously explained, RAPID is an acronym for “Remove Activities, Prolong Intervals
and Decreases duration”. In the following, the RAPID project is described in more detail.
Though the RAPID project focuses the effort on only one facility, the observations and
methods for improvements are expected to be useful to other Statoil facilities. The future
work does also include an approach to generalize the results from Heidrun and to produce
content to a “best practice document” within Statoil.
Remove Activities:
As seen in previous chapter there is magnitude of decade between the amounts of man-hours
carried out during a turnover onshore compared to offshore. The main reason for this is
limitations in berthing capacity offshore. Since we have this upper limit of daily man-hours
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capacity, there is a danger of prolonging the shutdown and consequently increase the
production losses. This, combined with the fact that turnaround work costs 30% more is a
driving force to remove activities from the turnaround scope of work. Our approach is first to
challenge each job candidate before entered into the turnaround work list in SAP by
investigating all means to perform the job during full production. Secondly, the work lists are
challenged, both regarding interval and duration. Since the organisation is “used to” having a
turnaround on a regular basis, it is quite a challenge to get the organisation to change its
behaviour. A key word in the change process is “opportunity maintenance”. As most of our
production units have low degree of redundancy or no redundancy at all, one has to use any
production trip or stop to perform maintenance. There must therefore exist pre-planned jobs
for any length of stop in production. It may also be situations where one will negotiate for
longer stops as an extension to a process trip to perform vital maintenance work. This requires
a close integration of the Operation and the Maintenance departments and a constant
cost/benefit optimisation. Since typical turnaround work includes welding and other types of
“Hot work” (Hot work during operation has up to now been banned in Statoil). To be able to
perform hot work in a safe manner, special precautions have to be made. This includes
welding habitats with overpressure in combination with automatic power cut on welding
device.
By excellent planning work and implementation of most recent welding safety precautions it
is expected that many typical turnaround activities can be performed during normal operation.
Prolong intervals
The second focus area in the RAPID model is to prolong the intervals between major
activities. In turnaround terms this is mainly inspection of pressure vessels and drums for
corrosion, and overhaul of large rotating equipments as turbines, pumps and compressors.
From experience we have learned that these inspections not seldom turn out with no findings,
as they hopefully should. If we had known this in advance, the whole activity could be
postponed to a time where we expect to find damage. This means that many labour and time
intensive activities could be saved. By applying existing and develop new condition
monitoring methods, vital process equipment is only opened and inspected when needed and
this will affect the time between turnarounds considerably.
For rotating machinery as pumps, turbines and compressors a variety of methods, techniques
and equipment is available and in use on our production units.
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The largest challenges are related to the areas of corrosion inspection and performance
verification of separators, pressure vessels and scrubbers. Since these equipments often are
insulated, they are hard to inspect from the outside during operation. Development of new
technology may be required.
Decrease duration
The third element in our concept is to decrease the duration of the turnaround. Since the main
objectives of the two first phases is to avoid work to enter the turnaround work scope the
main objective of this phase is to reduce the work further, in addition to plan and structure the
work in a manner that minimise downtime and production losses. Key elements here are a
strong turnaround planning organisation with authority to prioritise work to be performed, and
to exclude work that not have to be done within the time frame of the turnaround. Further the
turnaround organisation should have excellent planning skills and capabilities.
Example:
In the Heidrun pilot project, separator maintenance has been identified as the most critical
activity, both regarding duration and costs. Based on this fact, a considerable amount of work
has been performed, trying to challenge the separator work. In this case, a supplier is
responsible for performing the work, and several meetings have been performed together with
the supplier in order to identify improvement activities. The separator maintenance work was
divided into sub-tasks, where each sub tasks was challenged regarding time and costs. The
results for this work have been a long list of improvement activities, reducing the original
execution time estimate with 23 hours, from 117 hours to 94 hours.
The experience from the RAPID project so far is that considerable savings can be obtained
just by having a sufficient focus and a structured way of working.
ACADEMIC WORK
In general, turnaround activities are part of asset management and maintenance optimisation
in general. The fundamental system and process characteristics are defined in the design
phase of a facility, but there is always room for design improvement also in the operational
phase, if proven economical beneficial. Each turnaround activity is identified based on its
influence on production or other risk aspect, and is modelled as an activity with a duration
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and an associated cost. Each activity has an influence on production with three specific
phases: shut down period, execution period and start-up period. Obviously, the main reason
for grouping jobs in turnarounds is to minimize losses related to shutdown and start-ups. The
interval between turnaround activities is a risk optimisation problem (or a pure cost
optimisation problem if all risk elements can be measured in dollars). A long interval has high
risk for critical events whereas a short interval is costly due to lost production and the activity
costs. Activities governed by rules and regulations are not candidates for interval
optimisation. Based on the risk aspect, downtime costs and other relevant constraints, it is
possible to establish simulation models that calculates the costs of different turnaround
strategies, for example, the cost difference between having a large turnaround each year
compared to several small stops based on opportunities. There has been performed some
academic studies in the RAPID project. The result of this work will be published later.
In the future, more work will be performed related to mathematical optimisation of
turnaround strategies in addition to the more continuous improvement work. Students from
NTNU (Norwegian University of Science and Technology) play a vital role in this work
together with researchers from SINTEF/ MARINTEK. Also, it is planned to look further into
“global” optimisation of turnarounds in Statoil, taking all offshore and onshore facilities into
account, with their production infrastructure and various types of local and global constraints.
The main objective is to maximise the production, minimize the costs and to be a reliable
supplier of hydrocarbons to the market.
CONCLUSION
Our initial studies have shown that there are signification potentials of savings in optimising
turnarounds for our production units. The potentials are in magnitude of several million
dollars. The Heidrun pilot project has so far demonstrated that by ensuring high focus on
turnarounds and work systematic together with experienced personnel, significant
improvements can be obtain. In addition, more “academic” tools and methods can be
developed and implemented to further obtain savings. These methods will be investigated
further in future work, and a “best practice” related to turnaround planning and management
will be established for Statoil in general. To materialise these savings more effort must be put
into condition monitoring. New monitoring technologies have to be developed and the
planning capability has to strengthen significantly. It is important that turnarounds are not
seen upon as a special area, divided from other maintenance activities, but as a subset of asset
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management, with high criticality, that is, impact on production, safety, environment and
costs. In theory, a good design is to minimize maintenance that influence the production, but
it will always be a trade off between investment costs and operational costs related to this.
References
/1/ T.M. Andersen, Thorstensen et.al.; Aging Management: Aggregated Monitoring of
Technical Condition for Aging Equipment, 10th International Conference and
Exhibition Process & Power Plant Reliability, Houston, 2001.
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