2009 Mar 24. 19:36, Lu-Wan pipeline 2nd oil product pipeline project, 3000m HDD crossing through Yellow river main channel for China Petroleum & Chemical Corporation Sales company had announced a completion, which made a new historical record for HDD crossing length.
Zhengzhou-Tangyin 3000m oil product pipeline construction, with diameter 355.6mm and wall-thickness 10.3mm of oil product pipeline, and diameter 121mm and wall-thickness 8mm of cable pipeline, was regarded as a very harsh HDD crossing project. The pipeline was set to be went through a very complex geological condition in fine sand, medium coarse sand with gravels locally.
It was very difficult to drill over such a long distance pilot hole in sand layer without collapsing, unstable drill string and losing control of drill direction. To solve this problem, the team smoothed the hole to diminish the resistance, and assured the quality of the mud, meanwhile, fastened the pilot hole reaming by lower range and more series. To decrease super-long distance hole reaming torque and the risk of dill locking, we use the tech of Double-Driller Reaming. After twenty days hard work, we finished the reaming construction, and pulled back the main pipe with cable together once.