NASTT Abstract

Parametric Study of Pullback Forces on Pipelines Installed by Horizontal Directional Drilling (HDD)

Authors:
Ashkan Faghih, CCI Inc., Edmonton, Alberta
Anup Ghimire, CCI Inc., Edmonton, Alberta
Dave Dupuis, CCI Inc., Calgary, Alberta

Abstract
This paper reviews the design parameters for the pullback force calculation during Horizontal Directional Drilling (HDD) method. A comparison was made between actual measured pullback forces and theoretically calculated values for over fifty HDD projects. The study showed that the measured pullback forces were higher than the theoretically calculated forces for small HDD installations, while the results were reversed in the case of medium and particularly large HDD projects. Among many factors affecting pullback force, the design values for soil coefficient of friction, fluidic drag coefficient, drilling mud density and roller coefficient of friction are often assumed the same in the calculation for all different HDD projects.

A parametric study was carried out to show the significance of these design input values in the pullback force estimation. Comparison of the results with the actual recorded pullback forces suggested modifying the design values based on the specific design case in order to enhance the accuracy of theoretical calculations. Design of Experiment (DOE) methodology was also used to further study the significance of design parameters on pullback force. The study showed that the order of significance of the design parameters varied for different case studies and the impact of one factor on pullback force is relatively independent of the level of the other factors.

Publication Date: 2015

Presented at: 
NASTT’s 2015 No-Dig North Show, Denver, Colorado
March 15-19, 2015
Paper Number: WM-T1-01

For more information on this article, please contact Ashkan Faghih (ashkan.faghih@ccisolutions.ca).