Calculation of critical forces accompanying the installation of a high‑pressure gas pipeline in Mrzygłód, with trenchless HDD technology

The basic element providing the safety of HDD drilling jobs is properly selected pull force and torque. They also have an effect on the time of the realization of the wellbore and the cost of the investment. The professional literature offers a number of algorithms according to which the theoretically maximal installation force can be calculated. The calculated installation force values are presented in this paper, referring to some of the procedures used globally, and compared with the actual force encountered in practice. Real geological and drilling conditions are accounted for in the calculations. They are juxtaposed with the real forces recorded while installing a DN 1000, MOP 8.4 MPa gas pipeline. The discrepancies in the analytical results are explained. The paper closes with some conclusions and recommendations.