Well perforation

Perforation is the process of creating holes in production casing to establish communication between the well and formation. Perforation holes are used to recover formation fluid, as well as to inject into formation or annual space water, gas, cement or other agents.
Perforation is a tool used to perform perforation job.

Types of perforation

One of the perforation pioneers was bullet perforation patented in the USA in 1926. Holes in production casing were punched by amour-piercing bullets. Once bullet perforator was run in the casing, the charges fired. However this method had two considerable disadvantages: sticking of bullets in the casing walls and inadequate penetration into formation. Bullet perforation has become obsolete in our days.

In 1945 an American company introduced jet perforation. The performance of shaped charges was identical to that of anti-tank weapons – bazooka, accepted by the US army during the 2nd World War. Incandescent jet of directed shaped charge burns through the casing walls and forms channels by penetrating into bottomhole area. Jet perforation is still widely used today. However, the most significant disadvantage of it is percussion impact on production casing and associated negative consequences; disintegration of cement column above and below perfs, which results in channeling with close vicinity of water/oil contact. When using jet perforation, especially in terrigenic sandstones, glass gets formed in the wellbore part of the formation and the adjacent rock gets compacted, plugging heavily the wellbottom zone. Lack of a centralization system during blasting perforation may cause an axial displacement of the guns run in the hole, and after they explode it may cause local swelling spots in the casing and a number of poor quality holes and channels.

Combined Plastisoft™ Perforation emerged at the beginning of the 21st century. NEKKO has invented duplex slot perforator with two mill-disks which cut the casing walls by plastically deforming the metal. Hard mill-disk perforator reciprocates making the disks create mechanical loading on the casing thus inducing metals fatigue. As the pressure gradually increases in a certain period of time metal walls get deformed making lengthwise slots. The casing open-up pressure is hydraulically created with active fluid. At the same time two lengthwise diametrically opposed slots are formed in the casing. NEKKO Plastisoft™ Perforator is equipped with two fluid guns which can jet-wash bottomhole zone.


Tool’ exterior	Tool in-the-well view

Combined Plastisoft™ Perforation is a non-explosive tubing conveyed perforating technique which complies with advanced well operation.

Well perforation

Types of perforation

Tool’ exterior

Tool in-the-well view