Crossing the Yangtze

摘要

Alluvial sediments, a high tidal flow, heavy shipping traffic, 3,000m crossings and a strict six-month deadline all contributed to a complex pipeline installation under the Yangtze River. The combined challenges meant that conventional crossing methods to install the three parallel gas pipelines were limited and so CPP Crossing Company and Prime Horizontal decided on the intersect method. Intersect drilling from entry and exit effectively halved the length of the traverses and reduced the entry and exit angles, reducing the risk of becoming stuck. With no surface cables or obstruction it also posed no problems for shipping traffic.