Oil technology to check Rogfast Mountains – Aftenbladet.no

In a few weeks, the ship “Island Performer” in place in Boknafjorden to drill four core holes in Rogfast-line between Kvitsøy and Bokn.

– This is the first time this technology is used in conjunction with construction of underwater tunnels, and there is therefore great interest to it. We expect a good deal of visits when the boat soon dock at Randfontein Industries to be ready for the mission, said project leader Rogfast, Tor Geir Espedalsvatnet to Aftonbladet.

The geological investigations so far made by the bedrock has revealed that Rogfast will face varying soil conditions. Among other things, it conducted test drilling from Kvitsøy 1,000 meters into the race track.

But now want Highways Agency to form a better picture of long stretches of the route that can not be reached by drilling from shore. This is where offshore technology comes into play.

– Typical horizontal core drilling is only pinpricks along the route, now we want to drill long distances parallel to the planned tunnels, said Espedalsvatnet.

The company is VTT Maritime which has been assigned a value of 65 million, and will do the job along with the subcontractor Island Offshore and Baker Hughes. Core drilling will take place from the ship “Island Performer” which was delivered from the shipyard Ulstein last month. Shipowner Island Offshore was also the raising of “Wyveren.”

The longest stretch to be drilled along the tunnel route is 400 meters, after it has been drilled 192 meters lodrett down the mountain. In all, drill four holes at depths varying from 190 to 288 meters. In order to implement vertical drilling with such a short distance from the sea floor down to the areas to be examined, it has been necessary to develop new technology.

To make it possible to drill a sharper angle, use Coiled tubing instead of screwed tube, which is to be fed into the seabed from a specially designed construction. When corresponding bores occur in the North Sea is fed normally coiled tubing from the drillship. It is an Island Offshore, which owns and operates “Island Performer”, while Baker Hughes owns and operates coiled tubing drilling equipment.

The plan is to work in Boknafjorden begin on Monday 18 August and take about a month, and report on what is hidden in the rocks under Boknafjorden is expected to be ready within the year.

– Are you big surprises?

– No, not large, but it is important to document the rock masses in nature. Although the seismic surveys are good, we know, among other things, not quite the direction of crush zones, says Tore Geir Espedalsvatnet.

When the job is done and core samples extracted, the gaps will be filled in with cement.