Development of subsea infrastructure and intervention systems

The Seanovent team has extensive experience with design and development of all types of structures and piping modules needed for subsea production systems. This includes a multitude of foundations structures, manifold modules, distribution modules, jumpers and spools, pipeline support equipment and connection and intervention systems.

We utilize our cross functional team to develop the most cost-effective system solutions within the framework of client requirements and preferences and always looking for field architecture and hardware optimizations to reduce total cost for the Operator .

Through 30 years of experience within subsea developments in the North Sea, the Barents Sea, the Gulf of Mexico, Brazil, West of Africa, Caspian sea, the Mediterranean, North Atlantic and Australian waters the Seanovent team has played a central role in developing most types of subsea production system infrastructure. We are ready to support or fully take responsibility for development, design and follow-up of fabrication, testing and installation of:

  • Suction piles and mudmat foundations
  • Template and flow base solutions
  • CO2 and water injection manifold systems
  • Cluster manifold systems
  • Large bore gas manifold systems
  • Export manifolds, PLEM and PTS structures
  • Subsea distribution units (SDU)
  • Subsea coolers
  • PLETs
  • HIPPS modules
  • SSIV modules
  • Inline T’s
  • ROV and remote operated pig launchers
  • Tide water mill
  • Subsea separation systems
  • Connection and intervention systems
  • Tooling

Offshore renewables and marine industries

The subsea oil and gas industry and the renewable energy industries have differences, both in goals and technology, but there are also a series of technical and administrative areas where knowledge and experience can be transferred from one to the other.

The Seanovent team with extensive experience gained from subsea infrastructure is as such well fit to support infrastructure within the offshore renewables industry.

Typical areas where we can support:

Engineering and contractor integration and cooperation: 
Offshore renewable technology such as offshore windfarms and offshore hydrogen plants (topside or subsea) will involve many of the same technical disciplines and many of the same type of contractors as we see in the oil and gas industry. The technical integration work is therefore likely to be similar and also the interface work between the companies can be structured and planned in the same way. Lessons learned from one sector can as such be brought forward. The renewable industry has seen much progress the last few years. However, it seems to be clear that the sector needs to continue to reduce costs and continue to expand its reach into new markets, while also addressing environmental, health and safety aspects. The standardization developed in oil and gas can be used both at technical level, at specification level and in execution.  

Foundation structures: Bringing forward established understanding of how to develop, design and verify foundation structures located on the seabed, including geotechnical challenges and established work routines with geotechnical experts. The soil conditions have major implications for the design of all marine installations when they are resting or anchored to the seabed. This requires extensive seabed surveys and then processing of the data and finally an integration between the geotechnical findings and the actual steel structure.

Submerged steel structures, codes, load cases and material selection: It is important that the new industry does not start from scratch, but build upon the existing achievements in efficient design and material selection to minimize APEX and OPEX. All offshore assets, whether for oil and gas production or renewable energy generation, operate in the same environment. They experience harsh dynamic loads from winds, tides and currents and their operators face similar engineering challenges when designing, constructing, installing, maintaining and decommissioning them safely in the marine environment.

Piping and process systems: Design, material selection, engineering codes and documentation will all be generally the same.

Project execution: Renewables projects will have similar teams and resources, same project build up and likely many common challenges and goals as a typical oil and gas subsea project.

Based on the above, we believe Seanovent is well positioned to support early studies for renewable projects or support actual projects in many of the crucial areas. The team has extensive experience of supporting the offshore oil and gas industry at all development stages – experience applied for over three decades to reduce cost while still meeting all requirements. Our deep domain knowledge from the subsea industry covers a wide range of renewables disciplines, enabling us to offer already known solutions or find new solutions based on proven knowledge.   

Similarly, aquaculture is a growing business, both in Norway and in the rest of the world. In order to meet challenges with areas along the coast, the industry is looking into utilizing areas further out in the ocean. This will again result in need for developing subsea infrastructure for remote feeding and control. Seanovent Engineering can provide valuable support within project execution, innovative new solutions or standard pipe systems, structure system design and analysis.

Consulting services

Seanovent Engineering can provide engineering services and expertise to companies in need of a specialized skill-set within the subsea and marine industry. We have experienced engineers able to give short-term technical advice or enter into longer term contracts to provide:

  • Engineering support
  • Support or advice on project execution
  • Perform 3rd party verification
  • Perform peer review
  • Attend design reviews as an independent expert
  • Facilitate inspections, reviews or risk evaluations

Our consulting professionals will work with clients to define solutions to problems or to help determine and recommend the best course of action and as such save time, effort and money for companies that do not have the knowledge or expertise for handling a specific task.

Concept and product development

Concept or product development is typically driven by a general business demand or a specific consumer request.  It is Seanovent philosophy that success is best achieved based on a cooperation between our engineering team and customer/operator team. This will ensure all input and feedback in order to develop a product that deliver superior value to customers within the governmental and/or customer requirements.

Seanovent Engineering has a significant background from lead positions within concept development and detail engineering in the subsea Oil and Energy industry. Our combined experience covers subsea infrastructure all the way from the riser end, through effective field solutions and down to the subsea structure at any water depths, including ultra-deep water. We also have comprehensive experience with subsea lifting/replacement tooling and smaller ROV tools in addition to qualification and test equipment.

Areas of experience:

Field layout: Field layout optimization, pipeline and jumper reduction and smart solutions.

Flowlines/jumpers: Single bore, dual bore and multi bore types both pipe in pipe, piggyback and bundles. Optimized installation by installation method and integrated solution both for flowlines and umbilical.

Structures: Compact, simplified and cost-effective template and flow base solutions as well as large and small manifolds for oil and gas production or water and CO2 injection, both standalone and integrated modules for control distribution, integrated and standalone HIPPS modules, ROV and remote operated pig launchers, PLETs and PLEMs, reconfiguration of existing subsea structures, incorporate future tie-in modules and subsea separation.

Small and large foundations based on mudmats with and without driven piles, single- and multipile suction foundations, protection structures with and without fishing gear protection and tide water mill structures.

Connection systems: Both horizontal and vertical connection systems, connecting rigid or flexible flowlines, jumpers, umbilical, multi bore flying leads as well as flow modules.

Tooling: Component replacement tooling for typical choke modules, flow control modules, valve actuators and pigging loops. Installation tooling like manifold lifting frames, small and large spreader beams, flowline lifting tools, etc.

Test equipment: Bending and torsion qualification jig for small to large pressure containing couplings. Setup for thermal qualification of pressure containing equipment. Test jig for flowline, jumper and umbilical connection system qualification. Alignment test equipment for choke and flow control modules hook-up. Test equipment for well conductor hang-off simulation. Stretch bench for second end flowline lifting tool.

The Seanovent engineers have in total more than 25 filed patents within the Oil and Energy market.


The design, modeling and analysis of today’s subsea structures represents a major capital investment in subsea oil and gas production systems. By establishing effective design basis in compliance with industry standards, client requirements and critical interface parameters, we ensure a solid and cost effective  foundation for the design and verification process.

Seanovent Engineering features the right resources to properly establish your detailed design basis so that all relevant requirements are taken into account. This includes both functional requirements and regulations from industry and government/authorities that may apply. 

Depending on status of project, using either hand calculations, specialized code programs or advanced finite element analysis tools, Seanovent personnel can design and analyze complex offshore structural systems with confidence to establish and verify the capacity and function of the product using minimum material and manhours. We will supply innovative, persuasive, realistic, practical, co-operative and enthusiastic service on all your integrity verification tasks. 

Our experience cover management, supervision, verification and performing analysis such as:

  • Global analysis
  • Local analysis
  • Lifting analysis
  • Transport analysis
  • Pipe stress analysis
  • FEA for HISC analysis
  • VIV analysis
  • Dropped object and trawl protection analysis
  • Fatigue analysis
  • Code checks
  • Erosion screening

A wide range of standards and regulations, such as ISO, ASME, API, NORSOK, Eurocode and DNV are covered. We have had close relations with various specialized companies/resources  which makes it possible for our clients to get complete solutions for their projects.

Fabrication and test supervision

All engineered products will go through a fabrication and test phase to ensure that the quality and functionality meet the expectation and regulations/codes. Both fabrication and testing requires comprehensive preparation and planning to achieve a good technical result within schedule, budget and HSE targets, and this again requires knowledge of such operations and what can go wrong – everything from fabrication friendliness, yard capability and accessibility, fabrication methods/processes to test procedures, test equipment and test facilities.

The Seanovent team has through many years built up a unique competence on both fabrication and testing, domestically and abroad.

Fabrication: We have held positions such as site leaders, fabrication supervisors and site engineers in multiple projects spanning from fabrication of smaller items and systems and up to large subsea developments with up to 10.000 tonnes of fabricated steel.

Testing: Our competence cover multiple test stages, e.g. fabrication acceptance test, product qualification, system qualification, system integration test and shallow water test. We are capable of being responsible for procedures, site preparation and test execution, and have held positions as test engineer, test supervisor, test superintendent and test manager. In this manner we can support our customers directly in execution or we can review and consult in your planning or at site dealing with actual issues.

 Example of fabrication and test scope:

  • Subsea production system SIT and SWT
  • Subsea template and manifold, PLET and PLEM fabrication and FAT
  • Subsea Flowline and umbilical connection system fabrication, FAT, qualification test and SWT
  • Subsea tide water mill fabrication and FAT
  • Pressure containing connection system qualification test

Project control and execution

In Seanovent Engineering we have personnel with continuous oil and gas and marine project experience from the last 30 years from all over the world.  

Using recognized management methods will help you off to a good start, to control risks and keep your cost and time plan. However, every project lives its own life with its own challenges, scope, budget, stakeholders and priorities. This is where you need experienced resources. 

Our team of execution experts is recognized for its skills, agility, knowledge of industry challenges and not the least an ability to adapt to your needs. We can support your project team with experience for the complete duration of the project or consult you on smaller or larger issues.

You can count on our experienced and diverse team to meet each and every challenge:

  • Start-up routines
  • Organization/resources
  • Planning
  • Schedule review
  • Verification plans
  • Change management
  • Risk and opportunity management
  • Project audits
  • Customer relationship