Pipe in Pipe Flowline

A PiP (pipe-in-pipe) is a pipe inserted inside another pipe. The created intermediate annulus can be used to place an insulation material usually known as dry insulation. Indeed this insulation material is protected by the outer pipe from the hydrostatic pressure and from water penetration. PiP generally allow reaching optimized thermal performance compared with wet insulated lines.

ITP pipe-in-pipe flowline solutions are unique since they combine excellent thermal performance with a fast offshore Field Joint (FJ) technique.

On one hand, the ITP solution offers the best thermal performance in the market within the most compact design due to the features of the proprietary IzoflexTM insulation that can be described as follows: - Best as-installed thermal conductivity on the market (7mw/mK). - Mineral structure: silica based, no ageing. - Wide temperature application range (-195 to 900 °C/-320 to 1600°F) - Base material proven in industries such as aeronautics, automotive & nuclear since the 1960's - In operation since 1998 in subsea oil and gas flowlines. - Load bearing insulation: no need for centralizers, the IzoflexTM acts as a continuous centralizer due to its excellent compressive strength. On the other hand, ITP developed a specific Field Joint solution for J-lay and S-lay operations to achieve enhanced layrates and therefore reduce the cost of offshore installation by a factor of at least 2 compared with conventional PiP designs. Please refer to ITP Field Joint section. ITP Pipe-in-Pipes are suited for shallow, deep and ultra deep water as well as HP/HT fields.		Pipe-in-Pipe using ITP swaged end design

1. Pipe-in-Pipes for shallow and deep water applications

ITP systems are particularly well suited for shallow, deep and ultra deep offshore projects: - The pipe in pipe structure accommodates large hydrostatic pressure. - Due to the low thermal conductivity of IzoflexTM, only a thin layer of insulation is required to obtain highly insulated systems, which reduces the outer pipe size and thickness, thus reducing weight and costs (less welding time, less steel). - The compact & efficient insulation allows long tiebacks and long cooldown time. - For J-lay & S-lay, the specific ITP Field Joint (FJ) allows a quick offshore installation (one single weld offshore). - The ITP single/double/quad joint design offer integrated water stop and buckle arrestor every 12/24/48 metres.

Insulation of Quad Joints (48m/158ft) for DeepWater Rosa, Angola

Double Joints assembly yard, Forvie North project	Double Joints ready for collection, Bonga project

2. High Pressure/High Temperature

High Pressure (HP), typically 500bar+ (7252psi+) internal pressure, has a major impact on the flowline design since it can lead to very high wall thicknesses, which makes the fabrication and installation more complex (longer welding times, heavier system ...) High temperature (HT), typically greater than 90°C (194°F) , means that the system operates over a great temperature range between non-producing situations, such as installation, shutdown and the operational case. It implies the use of specific materials to address issues such as fatigue life. ITP offers solutions that comply with HP / HT requirements & constraints: - The insulation, IzoflexTM, can operate up to 900°C (1650°F) without any damage. - The high thermal efficiency of the system allows reducing the flowline thermal variations (increasing fatigue life). - ITP provided the first HP/HT PiP in the North Sea, the (SHELL ETAP project) operating since 1998 at 610bar-155°C/8847psi-311°F. Bibliography : http://www.itp-interpipe.com/products/pipe-in-pipes/pipe-in-pipes.php

Forvie HP/HT Project