Brownline recently surveyed a series of directional drills for the offshore grid connection project 'DolWin 6'.
Two sets of parallel drills with a distance of around 1,100 m / 3,600 ft were made from the mainland and two from the island of Norderney.
The drill trajectory would cross a dune area and breeding ground for many bird species and has since several years been named UNESCO world heritage site. The total project spans 90 km / 56 mi of cable connections (half of that on the mainland and half off-shore), which connect the wind farm to the German grid. The wind farm with a capacity of 900 megawatts is envisaged to be operational around 2023.
Complicating factors
- Zero tolerance for mud blowouts
- Very strict environmental restrictions
- Full time control
Centimeter-precise punch-out
Our Gyro Steering Tool (GST) was combined with GPS track, a tool that provides centimeter-precise punch-outs, even for long drills. The surface unit was placed on top of the drill path at 200 m / 650 ft and 100 m / 300 ft from the exit. The pilot drills have been a success because of the deployment of Drillguide GST and GPS track.