One of the key challenges along a combined onshore/offshore pipeline route is the interface connection. These installations require specialized construction techniques with minimum environmental impact and furthermore to meet the schedule of the pipeline laybarges. According to the specific project conditions, diameter, length and safety concerns, These sections can be installed in tunneled casings or using pipeline technologies, such as HDD or Direct Pipe®.
When HDD reaches its limits in permeable, heterogeneous ground conditions, the Direct Pipe® method is one solution to close this gap. Since 2007, about 110 pipeline crossings and landfalls have been successfully installed worldwide. Currently, Direct Pipe® is used in a growing number of shore approaches spread over the globe. The newly developed recovery module for remote disconnect of Direct Pipe® machine and pipeline before subsea recovery is a key innovation to realize demanding Direct Pipe® outfall projects.
Furthermore, tunnelling Technologies enable the construction of long-distance pipe jacked or segmentally lined casing tunnels out to the Sea to connect the offshore with the onshore section of the pipeline.
This paper focuses on the application potential of HDD, Direct Pipe® and tunneled casings and presents recent case studies.