Tuesday, May 20, 2008
Basic Drilling Concepts: Perforation
After the production hole is cased and cementing, now the well is ready to be perforated. Perforation gun is conveyed down the hole with the use of either wireline, drill pipe or coiled tubing. Wireline can be conveyed typically for wells with an inclination of <60 deg. This is because it is lowered by gravity.
Explosives are carefully positioned on the gun based on spf (shots per foot). Phasing is also used to describe the arrangement of the explosives. The charges are detonated either hydraulically (via drill pipe or coiled tubing) or using current (via wireline).
Different types of explosives will determine size of perforation tunnel, which connects the wellbore to the reservoir and temperature rating.