Jet Perforation
Firing is initiated electronically or mechanically by a detonation via the detonating cord which in terms sheds off primary explosive. The Primary Explosive detonated secondary main explosives. The explosive pressure on metal liner caused it collapsed inwardly (Towards inside). Along it axis forming a high velocity jets of fludize metal.
Liners are form from a mixture of copper, Lead, Zinc, tin & tungsten. First thing fludize metal comes out happens only, 15-16 microsecond. Whole process of jet perforation takes only 100 microseconds.
The tip of the particle, jet moves at a velocity of 25,000-30,000 ft per seconds which is equal to 8,000-10,000 metre per seconds. The develop pressure is in order of 5 to 15 mega pascals psi.
Under this conditions of material in its path flow parasitically under impact, the jet crushes the reservoir rock and displaces both the rock and fluid, radically from its axis. The entire perforating process from initial to completion last only few micro seconds.
Although the formation rock crushed and compacted it is not fused together.
Depth of perforation
Depth of perforation is only 2 inch - 20 inch
Entrance hole diameter
Entrance hole diameter is between 0.2 to 1 inch.
Common Terms used in Jet Perforations
Total Penetration
Inner line from casing + cementing + Reservoir penetration depth or you can say total impact depth
Formation Penetration
From outer wall of formation zone to total formation depth.
Notes:- Information is collected from our university notes. This is useful for any students and industry persons.
Article written & composed by-
Ritu Raj Medhi
President & Founder
Chief Technical & Editorial Officers
Petroleumbuddy Initiatives
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