Slotted Liner

Slotted Liner

Slotted liner or standalone screen is a popular sand control screen in long horizontal completions and low productivity wells. Precision slotted liners are manufactured by CNC controlled slotting machines or laser machine. All slots are de-burred, cleaned and drift tested according to API standards. Base pipe are per API casing or tubing specification with diameters from 1.5 inch to 18 inch. Pipe lengths of any diameter are available.

Sorts: API Base Pipe With Customized Slot Size
Length: ≤15m (each)
Outside Diameter: 2 3/8" - 20" (60.3mm-508mm)
Slot Number: as per customer's requirement
Slot Shapes: straight in line pattern, staggered pattern, spiral pattern
Slot space: as per customer's requirement

slotted casing pipe

Slot Size
Slot size including slot width and length is customized to suit customer’s requirement. For straight or keystone slots, minimum slot width is 0.012 inch and maximum slot width would be 0.25 inch.

1.5 inch long 2.0 to 2.5 inch long 2.5 inch long
0.012 inch wide 0.024 inch wide 0.078 inch wide
0.015 inch wide 0.025 inch wide 0.125 inch wide
0.016 inch wide 0.038 inch wide 0.250 inch wide
0.018 inch wide 0.048 inch wide
0.058 inch wide

Slotting Pattern

There are three types of slotted liner (slotted casing) arrangement:
A: refers to single staggered slots.
B: refers to straight slots.
C: refers to multiple staggered slots.
The edge of the slit is perpendicular, the cut edge is smooth, no burr, and the slit is even. The slotted pipe is treated with anti-corrosion treatment as a whole, and a dense protective layer is formed on each surface of the screen tube, which improves the corrosion resistance and wears resistance of the screen tube, and can effectively prolong the life of the underground working.

Slot Shape

Straight Slot
Straight slot has straight sides with equal width through the wall of the casing. It is normally used in consolidated formations or when slots of 0.030” or wider are specified.
Pros: Higher resistance to wear and more economical than keystone.
Cons: The possibility of clogging is higher than keystone slot.

Keystone Slot
Keystone slot is like a reversed “V” with narrower spacing at the liner surface and wider spacing in the inside casing wall. This shape allows for sand grains to bridge across the opening and ensures all the particles that enter into the hole will completely go through the wall.
Pros: Keystone shaped slots substantially reduce the possibility of clogging and improve work efficiency.
Cons: A little expensive than straight slotted liner.

Slot shape

Applications of Slotted Liner:
Laser liner pipe is a special pipe body installed at the bottom of seamless or welded steel well pipes such as oil wells, water wells, geothermal wells, and brine wells to separate the mined liquid from the sand in the stratum. Due to the basic structural characteristics of the formations involved, the particle size difference of the contact sand and the viscosity difference of the produced fluid, the specifications and shapes of the slits required by the screens are also different. In recent years, with the rapid development of China’s petroleum and geo-mine industries, the oil well drilling technology in the desert area has matured, the development of oilfields has increased in the middle and late stages, the rise of offshore oil production and the booming of geothermal wells, brine wells and deep wells. Development, the demand for laser liner screens is increasing.

Laser liner pipes (slotted casing) are widely used in old well regeneration of petroleum exploration, new oil wells and exploration (test) wells, offshore oil production wells and oil suction pipes for horizontal wells, side drilling, radial branching wells or open-hole, gravel packing The screen is completed and limited sand control is carried out. In people’s daily life, geothermal wells, saltwater wells, drought-resistant wells and domestic water wells are also screened for limited sand control. In general, the vertical shaft adopts a circular slit (hole) screen instead of the blasting perforation to eliminate many troubles caused by the ejection hole. To ensure that the sand is not caulked, the inner surface of the tube is wider than the outer surface to meet the requirements. With the huge increase in international oil prices, miners must increase the oil recovery rate of each well to reduce land occupation, save pipe body, reduce drilling costs and reduce oil production costs, in order to pursue greater profits. The original horizontal wells used mechanical, laser and other methods to process rectangular screens. Due to the permeability problem, mechanical slits and screen screens to make up for their shortcomings, lasers have been plagued by the laser processing screen industry for a long time because of the beam problem.

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