Pipeline Crossing

With the enormous number of pipelines and cables providing a complex network subsea, many pipelines have to cross existing infrastructure laid by other operators. Usually a minimum separation distance is required, therefore pipelines need to be lifted above the seabed to cross other cables and pipelines.

We provide multiple solutions:

Sleepers
Pre-filled Bulk Bags
Grout Inflated Fabric Formworks
Concrete Mattresses
X-Matt™

FAQ’s

Which product should be used for a pipeline crossing application?

The choice regarding which solution to implement will depend on the following:

Product type ie flying lead, pipeline
Crossing height
Clearance requirements
Pipeline lateral expansion
Scour risk
Available installation spread

What is the required height difference between 2 pipelines?

DNV standard prescribes a 0.3m minimum separation distance.

Will settlement have an effect on the sleepers?

When settlement issues can arise, the sleepers can be produced with a hybrid base of voided concrete and geotextile, reducing the weight while maximizing bearing capacity.

Can the sleepers be easily transported?

Most sleepers can be transported by barge or even by truck, when the large size of certain sleepers complicate transportation, they can be fabricated on a local quayside, removing costly logistics.

How can scour be controlled post deployment of pipeline crossing?

Scour can be mitigated by using mattresses to build the support or by including grouted roll out skirts on the sleepers. Fronded mattresses can also be deployed to assist with scour protection and remediation.

Run away scour at the touch down point can be mitigated by a mattresses or frond matts at the touch down point.

If lateral pipeline movement occurs at the touch down we recommend pre installing an X-Mat to effectively engineer in the touchdown support.