One thing I always wondered was why radio communication is banned during a perforation exercise. For those not in the know, perforation as explained by opcharlie is blasting through the production casing of a well so that hydrocarbons from the reservoir are able to make their way into the production string. Kinda like making holes in a blocked off straw so that your drink can enter the straw, and be sucked into your mouth.
‘Blast’ is the correct word, as explosives are used to perforate the production casing. The triggering of the explosives is done by a remote control. There is a concern that the inadvert triggering of the explosives may be caused by radio equipment. Hence, when a perf operation is underway, no radio equipment is allowed to operate. Portable handhelds may be recalled back from personnel, and an equipment tally is performed.
What I would like to know is, how many near misses / injuries / fatalities have occured due to radio equipment triggering perf explosives? This may happen if:
- the perf gun goes off before it enters the production string
- permature release when it goes off before reaching the required depth.
Wata - Malaysian Oil and Gas Engineer 
jabba needs to buy some of these explosive. As a sadistic dictator of a salt mine, it would be fun to strap some of these perf gun around my slave and get them to run. i can do an experiment to find out the range of my radio device then.
Oh by the way, you offshore guys must have some special mobile phones, i can’t get a decent signal sitting inside the toilet of my mobile operator’s building, but you can actually get signal downhole. amazing!
To jabba: I never said anything about mobile phones. Try hand-held radios. Another market you can corner.