Huayuan News
At 7:00 a.m. on July 2, 2012, the horizontal directional drilling (HDD) crossing project for the Wuhan–Guangshui refined oil pipeline through the People’s Liberation Army military restricted zone was successfully completed with the pipeline pullback operation. The crossing section had a total length of 736.55 meters, with a pipe diameter of Φ323.9 mm, and traversed primarily rock strata, including layers of highly weathered granite, moderately weathered granite, and slightly weathered granite.
The crossing site featured significant terrain undulation, with a height difference of 33 meters between the entry and exit points, making the HDD trajectory prone to deviation. To overcome the difficulties posed by this height difference and keep the trajectory deviation within the smallest possible range, Huayuan Company deployed its self-developed total station and steering system to monitor various drilling parameters in real time. Through multiple measurements, the optimal azimuth angle was calculated. During drilling, magnetic beacon positioning technology was also applied to monitor the drill bit location and adjust the drilling direction promptly, ensuring the exit point deviation remained within design specifications.
To avoid the military restricted zone and a military water well used for firefighting and daily needs, the pilot hole trajectory included several horizontal turns. Combined with the high hardness of the rock layers—exceeding 200 MPa—this made both pilot hole drilling and reaming operations exceptionally challenging. Leveraging its technical advantages, along with self-developed advanced steering equipment, precise surface tracking and positioning systems, and high-efficiency power reamers, Huayuan Company successfully completed the pilot hole and reaming work.
