Connecting offshore platforms to a subsea cable system

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Connecting Offshore Platforms to a Subsea Cable System

PTC’14Jerry Brown

Ocean Specialists Inc.Technical Manager – Subsea

Bangkok

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• This presentation covers some of the key points and lessons learned from the implementation of a 1300km long submarine cable system in the Gulf of Thailand.

• The driver for the project was to improve offshore communications (based on performance, reliability and security) by means of a fiber optic cable network.

• The Oil and Gas Companies chose to select a carrier model rather than take ownership of the subsea system

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• Oil & Gas Fields are busy areas, with regular crew boat services, supply vessel operations, helicopter flights etc. with platforms, subsea assets & other obstacles

• Restrictions on vessels entering the Oil & Gas Field.

• Vessels and the personnel onboard have to comply with Oil Company Marine standards, rules and requirements.

• Restrictions on operations / activities & equipment –

● What operations can commence / equipment can be used● Where operations can commence / equipment can be over-boarded and

landed on the seabed● Why operations are planned in detail and procedures are approved in

advance.● When equipment can be used (daylight working / 24 hour working) and

impact on other operations (SIMOPS reviews).

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• Oil & Gas Companies have a huge Influence on the project marine operations -

• Regular monthly project review meetings with all contractors, sub-contractors, suppliers and installers.

• The complex project activities were broken down into smaller logical work packages.

* Field entry - Vessel selection and acceptance* Where the cable is located - Cable Route design* Cable protection strategy* Crossing Agreements* Platform preparation for cable pull-in* Pre-rigging procedures for each platform* Site specific Last Mile Cable Installation Procedures* Main Lay Cable Procedures –

Grapnel operations, Plough operations, Buoy Off and ROV burial procedures.

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Oil Companies have requirements for all operations involving deployment of subsea cable, plant and equipment within Oil Fields and OCBs

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Typical Oil & Gas Company key project team -

• Project Manager

• Full Time Subject Matter Expert (SME) – knowledge of subsea cable, plant and marine installation equipment and vessels.

• Logistics co-ordinator - to provide central point of contact for all aviation and sea transfers of materials and personnel. All offshore accommodation bookings with Asset Managers.

• Dedicated Health and Safety specialist – training workshop and HA/JSA review.

• Marine / Geomatics Expert to assist with cable route design, marine safety and future expansions.

• Facilities Engineering to ensure platform structure (J-Tubes, Communications Room, Topside cable runs, interface OJB etc) prepared to meet project timescales.

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• Clear division of responsibilities

• Oil & Gas Company responsible for J-Tube construction & installation, Topside Fiber Optic cabling and supports from Optical Junction Box to the Equipment Room. Also for Power Supply with UPS within equipment room and mounting supports for terminal equipment racks. Logistics covering transportation of personnel and equipment to platform, accommodation and storage space on platform during construction and service periods, meals on platform.

• Contractor is responsible for all subsea cable works, cable pull-in operations on the platform, cable hang-off at J-Tube and cable routing to Optical Junction Box and completion of optical subsea to topside cable joint.

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• Presentation material prepared to engage with each stake holder group* Health & Safety* Facilities Engineering* Aviation Services* Marine Department & Marine Control* Asset Planners* Offshore Installation Managers OIMs

• Information distributed to office and offshore staff in good time, explaining WHAT, WHY, WHERE & WHEN … activities would occur• Seeking assistance and support when required• Resulting in EFFECTIVE COMMUNICATIONS, TEAMWORK.

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Documentation Reviews -

• Marine Installer is required to produce detailed vessel specific / project specific documentation and operational procedures.

• The procedures are developed to enable incident free operations.

• Extremely important when working on or close to platforms or in close proximity to subsea assets.

• Review of procedures by Oil & Gas Company can involve several departments and take considerable time.

• May take several review cycles before the documentation is approved by Oil & Gas Company.

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• Site specific / vessel specific operational procedures were developed, reviewed and approved before commencing any work – the main driver being to prevent incidents.

• Detailed procedures are developed to cover –Burial by cable plough Buoy deployment operationsGrapnel operationsEmergency procedures for Tug supportPipeline Crossing operationsDeployment of flexible mattresses

• Vessels were identified for specific tasks within the field, and DP audits, inspections and follow ups on all ships working within the OCB. Successful inspections were performed to ensure ships were qualified to the standard required by the Oil Companies International Marine Forum (OCIMF).

• The procedures covering preparation works on the platforms completed 6 review cycles before they were agreed by all parties. This contributed to the safe and incident free deployment of the cable onto the platforms.

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• Many tasks involving physical work on the platforms were required during the initial platform survey, equipment mobilisation and rigging activities, cable deployment phase and finally equipment de-mobilisation and making good any damage.

• These activities have the potential to affect other platform operations and so involved careful preparation, planning, communication and control at all times.

• The preparation, planning and communication of activities was aided by the generation of detailed procedures which were used to evaluate and assess risks through the Hazard Analysis and Job Safety Analysis (HA/JSA) process.

• The mitigation measures identified were rigorously enforced and documentation used to support Permit to Work (PTW) applications on the platform.

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Connecting Offshore Platforms to a Subsea Cable SystemTeamwork / Co-operation -

• During the As-Built J-Tube Installation QC checks, some errors in the J-Tube heading were identified at the last moment, just a few weeks before cable deployment and when procedures were almost complete.

• On 2 platforms the J-Tube heading mis-aligned with the planned cable route heading. The marine installer was very proactive and assisted the Oil & Gas project team to find workable solutions, which did not require rework of the J-Tube orientation, which would have caused significant delays.

• The vessel position for the cable pull-in operation was adjusted to minimise the mis-alignment.

• The mitigation measures taken resulted in incident free cable pull-in operations.

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Spares held on Cable Ship -

• During operations some delays were incurred due to broken equipment.

• As there were no spares onboard and operations had to be delayed until replacement parts were shipped to site.

• Service provider / Marine Installer to ensure sufficient spares are held for critical equipment such as ROV, survey system, plough etc.

• Prior to operations QC checks on equipment condition and to identify critical single source items. These QC checks should be completed as well in advance of operations as possible so that long lead time spares can be located and shipped to site.

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• As the Oil & Gas Company had adopted a carrier level approach as opposed to a direct purchase of a submarine cable system, their influence over the control and avoidance of project delays was somewhat limited.

• An accurate project schedule is important to the logistics process of ensuring the correct equipment and personnel were available on the correct platforms, without impacting other platform operations.

• Consideration should be given to identifying specific milestones against a deliverables timeline.

• To ensure a strong commitment to maintaining the agreed timeline between all parties penalty clauses should be agreed.

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• Effective communications result in a well informed workforce.• The inclusion of all parties in regular meetings ensures co-ordination, understanding and commitment.• Key messages were delivered to all relevant parties simultaneously so that these could be discussed and clarified if required.• The monthly meetings provided a forum for the regular review and discussion of the overall project plan and Marine POW, progress, deliverables and issues.• Operationally, the Kick Off meetings held on each platform was essential to ensure co-ordination between vessel and platform staff. The regular use of HA/JSAs and tool box talks at each stage of the operation was critical to successful operations.

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• Some Conclusions –• Oil & Gas Companies expect to be provided with detailed documentation to explain the WHAT, WHERE, WHY, WHEN type questions.• All operations have to be planned, reviewed and implemented SAFELY.• If any changes are necessary a Management of Change record is generated & approved before operations can proceed.• The system of controlling activities works with no injuries or incidents.

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Conclusion

Connecting offshore platforms to a subsea cable system

Engineering

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