Beyond the Yangtze River: part one

In January 2013, China’s Pipeline Bureau Planning, Shanghai Gas (Group) Company Ltd, commissioned CPP Crossing Company to manage a complex pipeline installation under the world famous Yangtze River in Chiangjiang City, near Shanghai, People’s Republic of China. Three parallel gas pipelines were planned under the Yangtze River and a strict, six month deadline was given to complete all three crossings.

In order to solve the multitude of problems encountered, CPP Crossing Company and Prime Horizontal conducted a feasibility study. The intersect method was selected as the best method as it offered the safest solutions to overcome the extreme conditions of the crossings. With Prime Horizontal’s track record of successful intersect drilling projects, the company was also selected as the guidance contractor.

Complex horizontal projects are often beyond the scope of conventional technology, either because the technology is not cost-effective or because the field problem itself is too complex due to drilling problems, extremes of local geology or long traverses.

These crossings were characterised by a high tidal flow, wide 3000 m crossings, heavy shipping traffic and alluvial sediments of soft sands and clays. The constraints meant that conventional crossing methods were severely limited, if not impossible. The soft sediments and long traverses would create high risks of becoming stuck in the hole with a conventional crossing. Intersect drilling from entry and exit effectively halved the length of the traverses and reduced the entry and exit angles, thus reducing the risk of becoming stuck. Shipping traffic would not be a problem since there would be no surface cables or obstructions.

Written by Prime Horizontal and edited from published article by Elizabeth Corner

To read the full version of this article, please download a copy of the February 2015 issue of World Pipelines.

Read the article online at: https://www.worldpipelines.com/special-reports/11032015/beyond-the-yangtze-river-part-one/