The pipes are replacing two existing pipes currently located in a parallel pipe bridge. The drillings were commissioned by VolkerWessels sister company Trapp Infra as part of the full relocation of both pipes commissioned by Vattenfall Europe Mining AG.
This is the first time that an HDPE pipe with a diameter of 1,400 mm has been pulled in. Furthermore, a unique aspect of the project is that, following the pilot drilling, the borehole was reamed to 70” (approx. 1,750 mm) in a single pass.
Both pilot hole drillings were executed on 11th and 12th March 2016. The borehole for the Ø 1,400 pipe was subsequently reamed, with the pipe string being used in the other (first) borehole as a return pipe (for the purpose of pumping round the drilling fluid). After reaming and performing a wiper trip (cleaning run), the Ø 1,400 mm pipe was pulled in and the drilling rig immediately relocated to the other pilot borehole.
This second pilot hole was then reamed to 60” (1,520 mm) again in a single pass, after which the second pipe (1,200 mm) was pulled in.
A first-rate collaborative effort concerning all parties involved (Vattenfall Europe Mining AG, Trapp Infra and Visser & Smit Hanab) made this project a success within an exceedingly short lead time.
Enclosed you will find an article about this project which was published in the Vattenfall-newsletter (in German)