Page 127 - Drilling Technology in Nontechnical Language

118 Drilling Technology in Nontechnical Language Second Edition

Fig. 5–7. Drilling tender with derrick on platform
Photo courtesy of Schlumberger.

In the North Sea, semisubmersible drilling tenders have been used to
support a drilling package placed on a platform.
Drilling tenders are used for development drilling from established
platforms. They might be inexpensive ($30,000 a day) for a barge-type
tender as shown in the photo to $100,000 a day for a modern semisubmersible
tender in the North Sea.

Drilling barge

A barge has a large, rectangular hull that floats over the well, anchored

in position. A derrick is positioned at the end opposite the accommodation,
on a cantilever over the hull. They can drill wells up to around 20,000 ft
(fig. 5–8).

Barges are used in shallow waters (up to 50 m) that do not have large
waves or strong currents. A number of these drilling barges operate on
Lake Maracaibo in Venezuela.

_Devereux_Book.indb 118 1/16/12 2:08 PM