What is Slotted Casing?

What is Slotted Casing?

Slotted Casing is a method of cutting multiple longitudinal or spiral straight-arranged and staggered slits of certain specifications on oil casing or tubing in various ways. It is made by using a special ultra-thin cutting sheet and beam cutting, with a slit width (0.2-0.5mm). The cross-sections of the seams are rectangular, trapezoidal (trapezoid angle is 3-8 degrees) and special shapes (round holes), which can ensure the permeability of 0.5%-10%. The layout of the seams can be processed according to user requirements.

The use of slotted pipes when extracting oil can filter out 99% of sand and dust, reduce the maintenance rate of oil pipes by 80%, and improve the strength, stability and continuity of sand and dust filtration in oil pipes, greatly improving work efficiency. Laser cutting can cut smooth, thin, high-density slits. The structure is simple and the effect is remarkable.

Advantages and features:

1. The slotted pipe is suitable for sand control in sand wells with a sand particle size greater than 0.3mm.
2. The edge of the cutting seam has good verticality, the cutting edge is smooth and burr-free, and the cutting seam is even.
3. Large flow area, 27/8” screen tube has 300 slits/1.5m, which is 2.4 times larger than the flow area of oil pipes of the same specification.
4. The overall anti-corrosion treatment improves the corrosion resistance and wear resistance of the screen tube, which can extend its underground working life.
5. The slotted pipe is made of J55 or N80 petroleum casing body, which has high strength and is not easy to deform.
6. Large inner diameter makes it easy to configure the pipe string.

The main technical parameters

Material: carbon steel, stainless steel
Pipe categories: oil casing, oil pipe;
Pipe length (single pipe): ≤15m;
Pipe outer diameter: 50~500mm (length ≤15m)
Wall thickness: ≤20mm;
Slit width: (0.10～4)mm ±0.03mm;
Number of seams: any;
Slit layout: parallel, staggered, spiral;

Performance and Specifications:

1. Slotted screen pipes Slotted screen pipes can be divided into two categories according to their uses: petroleum slotted pipes and water production slotted pipes, which use various steel grade pipes. It complies with the regulations of API Spec 5CT and China Petroleum Materials and Equipment Corporation's "Supplementary Conditions for Ordering Tubing and Casing" and adapts to various requirements.

2."PRS" screen tube ("PRS" screen tube includes: wire-wound drum screen tube, straight wire-wound screen tube, punched seam (FL) drum screen tube). The gap of the wire-wound screen tube can be in the base pipe ( (Oil, casing) can be precisely wound at will, and the seam width can be controlled within 0.15--05+005mm, which can meet the needs of downhole sand control. 

Stainless steel wire is resistant to acid, alkali, and salt corrosion, and the gaps will not widen due to corrosion. The filter sleeve of the slotted (hole) cylindrical screen is supported internally by the base pipe (sleeve, oil pipe) and has sufficient overall strength to resist the extrusion and deformation of the formation. Even if it is deformed, the gap in the pressure-bearing part will not increase, overcoming the This eliminates the disadvantage that when the punched screen tube is squeezed from the outside, the pressured part will reduce or close the gap under the action of external force, so the reliability of sand control is high.

3.Mosaic screen tube inlay

The screen parts of the embedded screen tube are made of special materials, so the gaps are small and evenly distributed. Although they are embedded in the tube body and fixed twice, they are easy to fall off. Laser oil slotted screens are an ideal product to replace the metal wire-wound screens currently used in oil fields. The sand prevention efficiency reaches 99%, reducing the oil well overhaul rate by 80%. The strength, integrity and stability of the oil well sand barrier are It has been improved, providing conditions for the realization of secondary sand control and multi-round steam injection production. To control long-stop wells, the advantages of high pipe joint strength, good sand control effect, and simple structure are fully utilized to fundamentally avoid the problem of "tangled wire" in the wire winding pipe. Slotted screen pipes are made with 0.10-0.5mm fine slits cut into the pipe wall. They are used in oil well sand control and other constructions. Its advantages are: good rigidity, scratch resistance, high strength, corrosion resistance, and uniform gaps.