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Are you maximising offshore production?

Friday, September 13, 2013

How can you be sure your offshore asset is producing as much as possible - and identify the easiest ways to improve production? Neil Wragg of GL Noble Denton explains how to do it.

Everybody wants to improve production from offshore assets, but how do you know if there is more you can do to improve production without incurring enormous costs?

To help answer this question and improve, oil & gas consultancy GL Noble Denton has developed a Reliability, Availability & Maintainability (RAM) software tool and service.

It looks at the commercial, design, operations and maintenance aspects of your operation, said Neil Wragg, Principal Consultant - Reliability and Availability with GL Noble Denton.

He was speaking at the Digital Energy Journal March 2013Aberdeen conference ''Improving offshore facilities management, operations and maintenance''.

The information can be useful to everybody involved in an offshore platform-because everybody cares about production - not just the maintenance managers.

The production rate is linked to the efficiency the plant is operating, how much shutdowns there are, and if the maximum production throughput is going through the system.

To manage operations costs, you need to work out which are the best are as to focus your attention - which systems and equipment are worth spending most time maintaining, because they have the biggest impact on asset uptime.

Commercial, design, operations, maintenance

Traditionally, people just looked at equipment reliability when doing a RAM model - but there is much more which needs to be taken into consideration, he said.

Optimising asset design is important, because bad design, or design decisions made without the full information, can be very expensive.

When it comes to operations and maintenance, ''it''s not just about how often equipment fails, it''s how easy they are to be repair, and is there a workaround for that failure?''

''What''s the right number of maintenance teams? What does a maintenance team constraint impose on our production? Could we achieve the same production levels with less people, could we improve production by more people? You have to understand logistics around getting maintenance teams offshore.''

Lifecycle

At the early design stage, different options are considered, which might have different capital expenditure costs, but also different operating costs.

The front end design stage looks at optimising the design, and identifying which pieces of equipment could have a bigger impact on production if they fail.

As the design progresses ''more information becomes available so we might see more information about maintenance strategy and operational strategy. But there''s a lot less we can do, things become more nailed down in the later stages of design.''

Once the asset is in operation, the main task is benchmarking performance and making predictions.

You can make a hit list of areas where improvements would make the biggest contribution to overall operations.

Quantitative

''The key thing about this approach is, we put in hard information from the assets and we get hard results out so we can make an informed judgment.''

''It cuts through a lot of subjectivity,'' he said.

Maintenance staff might tell you which items they are spending the most time on, but they might not be the most critical items for the asset as a whole.

For example ''the maintenance manager might be telling you that this pump is the biggest problem; the guys are fixing this pump every week. But actually that might be a spare pump so it''s not really hurting production.''

OPTAGON software

GL Noble Denton has developed the OPTAGON software for RAM modelling.

The software was first introduced over 20 years ago, when GL Noble Denton was part of British Gas, which wanted a tool to help model reliability of oil and gas facilities.

It uses ''Monte Carlo'' simulations, where a computer model calculates what will happen with different input data. ''What we''re essentially doing is ten thousand simulations, to look at likely outputs,'' he said.

You can generate information showing the cause of most of your lost production, so you can focus your attention most on those.

GL Noble Denton typically develops 2 OPTAGON models for each asset it works on.

The first model is made from historical data about the asset (including actual failure rates, repair times and logistic delays) - this data can be sourced from maintenance management systems like IBM''s ''Maximo''.

A second model can be built showing how the platform would operate if it was to achieve ''Industry Standard'' levels of production performance - data for this model can be taken from generic industry recognised sources of reliability data.

You can compare the two models, to understand in what areas the asset is under-performing compared to similar assets within the industry.

It is important to update your RAM model regularly, so it takes account of changes in how the facility is operating, and see how failure patterns are changing and performance of certain components is deteriorating.

Updating the model means you can take account of changes to the system, for example new tiebacks and modifications.

You can add in new data about actual mean time between failure of certain components, and your maintenance resource constraints (how many maintenance personnel you have available).

On some offshore platforms, Noble Denton has been doing this work since 2008, providing quarterly updates to the RAM model, so people get a continually updated idea about where problems are coming from and how the asset is performing, and what the likely production will be over the next quarter, taking everything into account.

Improvement plan

Once you have built the models, you can create and test out your improvement plan.

You can work out where you should focus and set goals, and what the maintenance costs will be. You can identify where you can achieve ''quick wins''.

You can get an idea of how much you can potentially produce, and how close you are to that.

You can answer questions such as, how much would replacing a certain pump affect performance?

You can see which equipment is deteriorating (its performance is gradually reducing). You can see what impact future design changes will have.

You can also look at the long term trends, and see if you are doing the right things, or what impact your work is having, which equipment is improving availability, which equipment is getting worse, and what recommendations there are.



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