Effect of shhot per foot (SPF) and penetration depth?

[2310abim]

Hallo, I'm Abim..
I'm new in oil production.
I want to know, how to know the effect of SPF and penetration depth of perforation to the productivity since the perforation is done and the well is producing?
Thank You very much.

 

[DrillerNic]

There's a free software from Schlumberger than can let you model the effect of shots per foot and penetration depth.

Usually it's a trade off between SPF and depth. Deep guns can shoot past any near wellbore formation damage, caused by the drilling process (skins, mud filtrate damage) or caused during the production process (scales). Higher SPF, means more holes, which obviously means more flow into the casing. This can be a major advantage in high rate gas wells where velocity and turbulence effects in the near wellbore area can be a problem.

One way to look at this empirically is to look at the well's PI (aka inflow curve): if it has declined over time, then reperforating/ adding more perforations may help.