Perforating
On a well site, to perforate means to pierce the casing wall and cement of a wellbore to:
- provide holes through which formation fluids may enter, or
- to provide holes in the casing so that materials may be introduced into the annulus between the casing and the wall of the borehole.
The gun shoots a bullet that perforates the casing and cement into the formation surrounding the wellbore.
Perforating is accomplished by lowering a perforating gun, or perforator into the well. The perforating gun is a device fitted with shaped charges or bullets that is lowered to the desired depth in a well and fired to create penetrating holes in casing, cement, and formation.
The perforation process includes the following steps:
- A specialized crew transports and operates the perforating equipment.
- Upon arrival to the site, the tools are assembled, then lowered into the well by a wireline unit or conveyed by tubing.
- The perforating gun then shoots small holes, or perforations, using shaped charges or bullets into the casing of the producing zone. The perforations allow the oil or gas to flow into the casing or liner. If the formation pressure is sufficient, the oil or gas will rise to the surface.
Knowledge Check Choose the best answer for the question.
5-4. After perforation, what criteria must be met before oil or gas will rise to the surface?
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