Page 320 - Hydrocarbon Exploration and Production Second Edition

Surface Facilities 307

Figure 11.39 Monopod system.

a line for the appropriate capacity, or to withstand operating conditions over the
field lifetime, can prove very costly in terms of deferred oil production.
Long pipelines are normally installed using a lay barge on which welded
connections are made one at a time as the pipe is lowered into the sea. Pipelines are
often buried for protection as a large proportion of pipeline failures result from
external impact. For shorter lengths, particularly in-field lines, the pipeline may be
constructed onshore either as a single line or as a bundle. Once constructed the
pipeline is towed offshore and positioned as required. It has become common
practice to integrate pipeline connectors into the towing head, both for protection
and easier tie in (Figure 11.40).