Page 121 - Drilling Technology in Nontechnical Language

112 Drilling Technology in Nontechnical Language Second Edition

Heavy and light land rigs might include accommodation for the crews,
or the crews might be accommodated elsewhere while not working (in a
hotel or a central camp, for instance).

A light land rig might cost around $25,000 to $40,000 a day.

Helicopter transportable land rig (heli-rig)

In remote areas where suitable roads do not exist, a rig can be placed on
location by helicopter. A heli-rig can be broken down into small packages;
the maximum package weight will be around 6,000 lb. Heli-rigs are used
in jungles and mountainous regions.

On heli-rig operations, everything is transported by air. The heaviest
loads are lifted early in the morning because the air is coolest and the
performance of the helicopter the highest.
A helicopter will generally be stationed at the wellsite when not in
use, so that it is immediately available for medivac, or emergency medical
evacuation, in the unfortunate event of an accident requiring medical care
beyond that provided on the rig.

Heli-rigs will include accommodation for the crews.
A heli rig might cost around the same as a heavy land rig, depending
on the capacity. Running costs apart from rig cost will tend to be higher
because one or two helicopters are kept with the rig.

Automated singles rig

One of the recent developments in rigs is for highly automated rigs that
use pipe handling systems to lay down all the drillstring components when
pulling out of the hole. It might or might not have provision to rack a few
things vertically in the derrick. An example of this is the Drillmaster rig,

shown in figure 5–3. The rig is truck mounted; it is raised off the ground
on a frame, and the derrick pivots upright. Rather than a wire rope, the
block is moved by a hydraulic ram. In front of the rig is a magazine, where
drillpipe, casing, and other tubulars are stored vertically.

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