World Record 5.2 km HDD Twin Crossings of the Hong Kong Harbor

To meet the fuel demands of the expanded Hong Kong International Airport (HKIA), new twin aviation fuel pipelines were installed using horizontal directional drilling (HDD) by Langfang Huayuan Mechanical and Electrical Engineering Co., Ltd. The new pipelines included two parallel pipes with drive lengths of 17,060 ft. (5.2 km) each, a diameter of 20” (508 mm), and a buried depth of 330 ft. (100 m) under the seabed. The $1.3 billion HKD ($165.63 million USD) project started in early 2016. The first pipe installation was completed on December 27, 2017, and the second on March 9, 2018. The overall project duration was 30 months, which included 6 months for onsite preparation and 4 months stoppage due to the breeding season of the egret, a small bird. The length set a world record for HDD. As expected, the pipeline installation experienced numerous difficulties and challenges including pilot hole directional control, drilling fluid management, reaming torque, pullback force, and project management. The contractor optimized HDD intersect technology with an innovative “handshake” pilot hole drill-bit for the crossing. Additionally, they also utilized a global position system (GPS), sea surface ship positioning system, and geomagnetic sensing system to accurately guide the pilot hole. In order to reduce the reaming torque, a series of unique specialty reamers were developed for the extra-long distance reaming process. Accordingly, the contractor used a novel high-performance drilling fluid to meet the requirements of cuttings transportation and borehole stability. During the pipe pullback process, a redesigned thruster was used to protect the anticorrosive coating of the steel pipes. Additionally, the modular equipment accelerated the construction period greatly. With the aid of innovation and key drilling parameters, the contractor completed the world’s longest HDD crossing project successfully. Experiences learned in this project can be used as the HDD industry continues to break distance records.