Case Study of Productivity Analysis for Horizontal Directional Drilling

Horizontal Directional Drilling (HDD) is a steerable system for the installation of pipes, conduits, and cables in an underground bore-path created by a surface launched drilling operation. HDD is the most suitable technique for crossing beneath obstacles, such as rivers and lakes, highways, or special areas such as airport runways. Additionally, HDD is a suitable and cost-effective method for constructing new water and wastewater pipelines where excavation is not practical or possible. HDD operations are capable of traversing various soil conditions and meeting a wide variety of project requirements (pipe size and material, placement distance and depth). Nonetheless, the specific soil conditions and project details are important factors in determining the productivity of the overall operation, and these conditions must be carefully investigated during the HDD design phase. The present case study provides observed HDD productivity values (ft/hr) during pilot-hole operation in different soil formations (shaly clay, sandy shale, and silty clay). The case study also provides the variations in HDD productivity during the reaming stage based on the soil and project conditions encountered (diameter, depth, and length of borehole), while other conditions (e.g., contractor, and HDD machine) remain constant.