Bibby Offshore – logistics case study: unlocking subsea productivity

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Submitted by Vikki Thom (Subsea Business Manager)

Problem statement

The current climate has resulted in short inspection, repair and maintenance (IRM) scopes being deferred, delayed or cancelled as they are not viable to carry out on a stand-alone basis.

Aims

  • Share equipment and vessels over multi campaigns and operators to reduce non-productive time.
  • Demonstrate cost savings by increasing schedule efficiency.

Method

  • Framework with key clients
  • Dedicated project delivery team
  • IRM campaign builder database
  • Schedule control to support turnaround (TAR) shutdown and opportunities in the vicinity
  • Managing and minimising risks across campaigns
  • Streamlining processes

Impact

  • Sustainable campaign management resulting in traditional project costs being significantly reduced.
  • Innovative working relationship with operators and supply chain.
  • Non-productive time managed.
  • Value chain opportunities and economies of scale realised.
  • Efficient framework for a cohesive approach to project delivery.

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Proserv deploy abrasive cutting from a semi-sub on North Sea wells decommissioning project

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Submitted by Proserv

Impact

Proserv’s Multi-String Cutting (MSC) tooling was efficiently integrated with the drill pipe and recovery operations were optimised to allow the recovered wellheads to be removed from Proserv’s tool string without disconnecting the control lines or the tooling from the drill pipe. This minimised the time between deployments to the time required to skid between the wells.

Through the deployment of Proserv’s MSC tool the operator was able to achieve a smooth frictionless cut through multiple casing strings, cemented or not, in one trip. The rigidity and control of the drill pipe coupled with the sealing mechanism on the Proserv MSC decreased cutting times by around 25  per cent. This ultimately contributed to the successful, safe abandonment of the eight wells, well ahead of schedule.

The use of abrasives cutting technology, as part of a plugging and abandonment campaign from a semi-sub drilling rig, is believed to be an industry first in the North Sea.

Description of Best Practice

Proserv was contracted by a North Sea operator to abandon eight Category 1 subsea wells from a semi-sub drilling rig using our Multi-String Cutting (MSC) tooling, which uses abrasive water cutting technology. This tooling has an established track record in the Gulf of Mexico from vessels and platforms, and was introduced into the North Sea in 2014. Proserv has a successful track record in the North Sea of abandoning more than 20 Category 1 wells for multiple operators from light well intervention vessels. For this work scope, Proserv’s MSC tooling was deployed from a semi-sub rig using drill pipe. The MSC assembly was integrated with a wellhead retrieval tool that latches into the profile of the camhub wellheads. This allowed the cut and recovery of the wellhead to be carried out in a single trip regardless of casing configuration.

Over the course of nine operational days including recovery of the wells to deck and skidding the rig, Proserv successfully abandoned all eight wells. The well architectures had a variety of casing designs ranging from 10.75 inch through to 30 inch conductors.

Contact: Stewart Macindoe
Stewart.Macindoe@Proserv.com

Maersk Oil – Optimising to remove risk: 80 per cent cost saving on inspection of flexible hoses

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Problem Statement
An alternative method for inspecting flexible hoses on the Gryphon Alpha Floating Production Storage and Offloading (FPSO) vessel’s turret, which removes the need to use radiography was needed. Radiography cannot be carried out in the direction of the asset’s nucleonic detectors as this will trip the high-integrity pressure protection system (HIPPS) and cause an unplanned production outage. The entire turret area needs to be shut off to personnel during scanning as it poses a significant health risk. This prevents routine operations from taking place in the vicinity. Radiography was carried out over nine months but this only achieved around 50 per cent of the required work.

Aim
To inspect flexible hoses in a more cost and time effective manner while reducing personnel exposure to ionising radiations and spurious plant upsets.

Method

  • The Maersk Oil team engaged with innovative inspection specialist, Innospection, to investigate alternative techniques.
  • Innospection was already using Saturation Low Frequency Eddy Current (SLOFEC), an electromagnetic technique, on subsea risers so the team worked to adapt this technique for the much smaller flexible hoses on Gryphon.
  • A bespoke tool, small enough to work successfully with the flexible hoses, was developed and tested onshore.
  • To test, an old section of flexible hose was intentionally damaged onshore to see if the tool picked up the discrepancy, which it did.

Impact

  • Developing the tool and validating the technique took around six months.
  • It was then trialled offshore on the Gryphon Alpha FPSO where it scanned all of the six-inch flexible hoses, around 40 per cent of the turret system, in just two weeks, providing better coverage while delivering the required image quality.
  • In the past, radiography was carried out over nine months of the year, but this only achieved around 50 per cent of the required work. The new tool has proven to be a much more efficient method.

Total time saved: Significantly reduced. Only two fortnightly trips are now required.

Total savings anticipated: Over 80 per cent over the next five years

Click on the image above to download the case study.

Lokring: Lessons in pipe connections from the British MOD

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Submitted by Jake Rowley (Technical Sales Engineer)

Problem statement

  • During construction of the first British MOD Astute Class submarine, it was found that welding on small bore pipework was causing huge delays to the schedule.
  • For the duration of the weld, fire watch and post-weld non-destructive testing, all other 350 staff working within the vessel had to cease work and evacuate causing drastic delays to the schedule.

Aims

  • Reduce delays for the additional six Astute Class submarines and ensure delivery on schedule.

Method
In order to reduce delays, the British MOD looked for alternatives to welded pipework. Lokring provides a safer, faster and cheaper alternative to welding, without compromising integrity.
Given the criticality of the systems (missile launch hydraulics, fire water, steering hydraulics. etc), Lokring had to undergo highly stringent testing to prove it was up to the job, including:

  • 1,000G shock test (to simulate a depth charge or missile strike)
  • Vibration test with 10 million cycles and 500,000 pressure pulsations

Impact

It was found that only Lokring or properly done butt welds were suitable to be used. As a new build project there were no restrictions to welding, however, the speed of install offered by Lokring and the ability to stack trades saw over 7,000 Lokring fittings used on each of the Astute Class submarines and over 12,500 on both the aircraft carriers (HMS Queen Elizabeth and HMS Prince of Wales). It was suggested that the introduction of Lokring reduced hours spent constructing small bore pipework by over 90 per cent.

How does this relate to the oil and gas industry?

An operator in the southern North Sea recently replaced a diesel ring main on one of its offshore platforms. Initial plans, using pre-fabricated spools to be tied-in using flanges, came in over budget. An alternative method was therefore required and, by adopting the techniques used by the MOD, it was proposed that Lokring was used to construct the entire system offshore (site-run).

By changing the mind-set from “we always do it this way” to looking at alternative methods already used in other industries, the operator was able to make significant savings in both cost and time.  The operator took a product it was already using, Lokring, and combined it with a technique used by the British MOD. By doing so, they reduced offshore construction time by over 1,000 hours, freeing up bed space and allowing workers to move onto the next job. The cost of site-running Lokring came in 28.5 per cent cheaper than the pre-fabrication method.

Site-running with Lokring is becoming more and more common in the oil and gas industry, helping operators to complete projects efficiently and within budget.

Total hours saved: 1,288

Total savings achieved: 28.5%

Click on the image above to download the case study.

SETS – Applying subsea standardisation principles to conductor repair

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Submitted by Kevin Milne (Business Development & Brand Manager)

Problem statement

Delivery of safe conductor investigation and intervention operations through the splash zone on fixed assets typically requires the use of a dive support vessel (DSV), which is time sensitive and expensive. Alternative approaches offer the opportunity to make substantial efficiency savings without compromising safety.

Aim

  • Test application of standardisation (fit-for-purpose) principles to use alternative approaches to repeatable cleaning, inspection and repair operations through the splash-zone on wells/conductors and caissons.
  • Reduce operational expenditure (OpEx) on otherwise economically viable assets.
  • Increase integrity data and management.

Method

We took a commercially and technically de-risked approach to OpEx scopes. The SETS team collaborated with the asset owner to understand operational drivers, and the use of data collection for decision making to achieve better results. These discussions were used to develop the best fit-for-purpose solution.

Impact

  • Application of the standardisation/fit-for-purpose principles provided proof of concept for the new techniques for repairs that were adopted.
  • New tooling was developed.
  • Innovative methods for rope access were deployed.
  • Cost savings on these alternative non-DSV approaches were realised.
  • Rope access techniques and tooling delivered in splash-zone also permitted deployment of repairs in depths of up to 15 metres.
  • Produced repeatable methods for asset inspection, resulting in better data and integrity management
  • Facility for completing multiple repairs in short time window.
  • Budget reduced by over £6 million for client.

Total hours saved: 552 DSV hours

Total savings anticipated: £6 million+

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Halliburton – Vendor Managed Inventory

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Submitted by Halliburton

Impact

The average consumable spend per workshop hour Dec-14 to Jan-15 was £2.04 per hour.

The average consumable spend per workshop hour in Jan to Mar-16  spend was 81p per hour (i.e a 60% reduction in consumable cost per workshop hour)

Not included in the above figures are the saving and reductions that Vendor Managed Inventory (VMI) machine provides in the following:

  • inventory stock holding (releases working capital);
  • saves admin/processing time on: raising purchase requisitions/purchase orders, goods receipt, storage/counting, goods issuing; and most importantly,
  • saves the workshop technicians time in them walking to the stores to ask for basic consumables.

Description of Best Practice

A VMI machine was installed and became operational within one of Halliburton’s workshops in Aberdeen in March 2015. These machines hold fast moving consumable workshop items such as PPE, abrasives, glues, tape, aerosols, etc, and allow technicians controlled access to withdraw these goods straight from the machines instead of the traditional trips to stores or raising requisitions. Not only do these machines save the technicians time but they avoid the entire requisition/purchasing/invoice processing effort/costs involved with traditional sourcing as the contents remain the property of the supplier until used. The machines are connected directly to the internet and send stock usage info to the vendor’s office 3 times daily so that replenishment (against min/max levels) can be planned multiple days weekly as required. Monthly billing and online interface simplify administration while allowing detailed reviews of usage patterns. Swipe card security, touch screen and photo catalogue interface makes average “picking time” circa 15 seconds.

The VMI machines are supplied free of charge by the vendor and set-up costs are very minimal (electrical power and a native internet connection) and the machines are reconfigurable and can be relocated.

The usage of the machines is monitored and weekly and monthly usage reports are automatically e-mailed to facility supervisors and materials for review – supervisors were easily able to identify unusual or excessive use and challenge individuals.

Contact: John Suggett
john.suggett@halliburton.com

Nexen – EPC/operator collaboration successfully changes out single point failure equipment on Buzzard

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Submitted by Nexen

Impact

  • Nexen Petroleum U.K. Limited in collaboration with Amec Foster Wheeler successfully changed out one of the largest shell and tube reboiler heat exchanger bundle on the Buzzard installation during the 2016 Turnaround (TAR).
  • This was the first time this bundle, a single point failure for the processing facilities, was changed out since the Buzzard field was constructed in 2007.
  • The change-out workscope required engineering of movement corridor, the removal method and detailed sequencing of the removal c/w complex lift plans.
  • Plant clashes were resolved outwith the Buzzard TAR period, and the main bundle change out was managed during the TAR period with no detrimental impact to TAR duration.

Description of Best Practice

In line with vessel integrity inspection requirements, Nexen set out to a complete inspection of the amine reboiler shell vessel during the Buzzard 2016 TAR.

To ensure a best in class inspection was carried out, it was determined that the reboiler bundle would be withdrawn from the shell. Given the single point failure status of the unit operation, the bundle would be subsequently replaced with new equipment on reinstatement.

Driven by the duty of the exchanger, this was one of the largest bundles on the Buzzard installation at  16.4T, 1.7m diameter x 7.3m length, however it was located in a challenging position on a mezzanine deck within the process facilities deck. The weight of the bundle (with movement and lift cradles) approaches the capacity of the platform crane at minimum radius.

As this was is the first time the bundle had been changed within Buzzard production life, it was necessary to identify the extraction route and sequencing of the bundle movements to ensure no detrimental impact to the TAR duration.

This involved close collaboration between Nexen and the AmecFW team in engineering the extraction route, methodology and sequencing to minimise the impact on pre-work and shutdown duration, whilst offering the most stringent level of safety mitigations. Significant benefits were realised through this collaborative approach, with a strong focus during the scoping phase on the various methods available for such a complex activity.

The execution strategy was then confirmed by a  full onshore mockup trial that recreated offshore deck plan and validated the selection of air skates as the motive solution. The onshore trial also identified further safety and operational enhancements which were then incorporated into the final execution strategy.

Execution of the change out was completed and successfully managed within the planned TAR period.

Contact: Tracey Miller

Tracey.Miller@nexencnoocltd.com

Nexen – System Scaffold reduces risk of Confined Space Entry (CSE)

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Submitted by Nexen Petroleum U.K. Limited

Impact

Safety First – The use of System Scaffold resulted in a reduction in manual handling and the duration of personnel working within a confined space.

In total a 66% reduction in man hours was achieved using the System Scaffold.

The excellent team work and collaborative effort between Nexen and Stork resulted in the work scope being completed on time and without incident or accident.

Description of Best Practice

During the Buzzard 2016 turnaround, invasive maintenance was required on the first and second stage production separators.  Part of this activity required internal access to the vessels to erect scaffolding, which involved the hazard of entering and working in a confined space.

The Stork System Scaffold was not only quicker to erect and dismantle, with fewer components, it also required less manual handling and transportation of materials – which was particularly beneficial given the confined area where the worksite was based.

The use of System Scaffold resulted in a reduction in manual handling and the duration of personnel working within a confined space.

To reduce the risk of Confined Space Entry (CSE), System Scaffold was adopted as an alternative type of access.  This type of scaffolding could be erected and dismantled quicker than conventional ‘tube and fitting’ type scaffold.  It meant that there were significantly less components and eliminated the requirement for numerous fitting connections.

Contact: Tracey Miller

tracey.miller@nexencnoocltd.com  

Nexen – Innovative lance cleaning system washes gas cooler exchanger tubes in-situ

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Submitted by Nexen Petroleum U.K Limited 

Impact

The duration of the cleaning work scope was reduced by 72 hours, compared to the original forecast using traditional cleaning techniques.

The benefits of using the dual lance cleaning system resulted in a reduction in risk to personnel, manpower requirements and duration of workscope.

The system yielded superior cleaning results and an improved understanding of the inspection/integrity findings.

Description of Best Practice

The 2016 Scott Platform turnaround included a critical path workscope to clean the Dehydration Feed Gas Cooler.  A combination of simultaneous operations and the design of the facilities necessitated that the exchanger tube bundle could not be removed, which meant that the exchanger tubes had to be cleaned whilst they remained in the exchanger shell.

Nexen’s turnaround team investigated techniques and technology to use in this workscope and discovered a solution based around lance cleaning systems.  This lead the team to investigate a dual lance cleaning technique used by Stone Age.  The benefits of using the dual lance cleaning system were found to be a reduction in risk to personnel, manpower requirements and work scope duration.

The company Stone Age were affiliated with Stork, with whom Nexen already has a contract, which enabled Nexen to further look into how the cleaning method could be used on the Scott Platform.

Through collaboration between Nexen and Stork, resulted in Stork purchasing the cleaning facilities and technique.  Trial runs onshore were subsequently conducted, which were vital in ensuring the system worked proficiently.   The successful offshore execution of the cleaning was the result of excellent team work and collaboration between Nexen and Stork over the course of about 6 months.

Contact: Tracey Miller 

tracey.miller@nexencnoocltd.com

Chevron and core supplier Schlumberger collaborate to save millions of pounds on Alder

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As part of Chevron Upstream Europe’s (CUE) ‘total cost of ownership’ approach to ensuring a sustainable business, the company identified that silo working was creating the potential for missing delivery deadlines. To resolve this, CUE forged a closer working relationship between both its drilling and completions and supply chain management teams and one of its core suppliers, Schlumberger. CUE ensured the right people were in meetings to enable quicker decision-making and Schlumberger made a senior executive available for liaison at CUE’s office on a weekly basis. On the Alder project, this enhanced partnership helped resolve numerous technical, quality assurance, on-time delivery and commercial challenges resulting in expected savings of around $5.7 million. More detail on the approach taken is available here and a short film can be viewed here.