The IEA’s Offshore Energy Outlook (2024)1 marks a notable shift from investment in shallow water to deepwater assets. As shale oil starts to level off, there is an increased need to tap into more expensive to produce oil in challenging and complex reservoirs. This increases the attractiveness of deepwater projects, as well as smaller onshore fields and less productive areas, but it comes with its own set of challenges.
As operators push further into harsher environments, the limitations of conventional steel pipelines are becoming more visible; corrosion, fatigue, and logistical challenges in remote locations are delaying projects and increasing the total cost of ownership. Thermoplastic composite pipes (TCP) are emerging as a credible, field-tested alternative that addresses these issues head-on.
TCP Jumpers have been successfully used for several years now, mainly for water injection, gas injection, or water alternating gas (WAG) applications. To enable the use of TCP Jumpers as production jumpers, Strohm developed an insulation solution which can be used in combination with either its carbon fibre and PA12 composite, or the next generation high temperature resistant composite material based on carbon fibres and polyvinylidene difluoride (CF-PVDF).
Cold and high-pressure subsea fields
Recent developments show how insulated TCP solutions can maintain flow assurance in cold, high-pressure subsea fields without compromising weight or flexibility. In a recent paper, thermoplastic composite pipe (TCP) producer Strohm presented its application towards an insulated production solution for temperatures up to 93°C (200°F) and the testing carried out to confirm the product viability for these extreme temperatures.
An optimal insulation solution for TCP must not only meet the required heat transfer coefficient (U-value), but also take the system’s on-bottom stability into account, given that TCP is relatively light. Additionally, the insulation must not negatively impact the TCP’s flexibility and its ease of installation, particularly when it comes to subsea pallet deployment. This means the insulation must provide adequate submerged weight while maintaining the installation efficiency of the system.
An insulation solution based on polyurethane half shells, with integrated ballast, was selected and further optimised during detailed engineering. In alignment with the standard for TCP (DNV ST-F119), a key element of the qualification was to prove the system’s predictability and validate its performance.
U-values were measured on bare TCP and on TCP with insulation. In both cases, during the test conditions, the measured U-value was found to be very close to the calculated values, therefore proving its predictability and validating its performance. In dry conditions the measured U-value was 1.0 W/m2K, corresponding to a U-value of 3.9W/m2K in submerged condition.
However, an optimal insulation solution for TCP must address more than just achieving a specific U-value. Due to TCP’s relatively low weight, on-bottom stability must also be considered. Additionally, the insulation should not compromise the installation benefits of TCP jumpers, particularly their compatibility with subsea pallet deployment. In other words, the optimal insulation solution must be flexible and easy to install – which are key features of the TCP Jumpers – and must have sufficient submerged weight when delivering the required insulation properties.
1. https://iea.blob.core.windows.net/assets/140a0470-5b90-4922-a0e9-838b3ac6918c/WorldEnergyOutlook2024.pdf
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