What Is Slotted Pipe
Slotted pipe, also known as perforated pipe or well screen, is primarily used to allow liquids or gases to enter or exit a pipe while filtering out solid particles such as sand, soil, or gravel. The slots are cut into the pipe wall by machining or laser, and their width, shape, and density are selected according to the formation and flow requirements. Depending on the material, PVC, HDPE, or steel, it serves water wells, drainage, oil and gas, landfill, and civil engineering applications.
Water Well Construction
The most common use of slotted pipe is as a well screen in water wells. It is placed at the bottom of the well in the water-bearing zone, or aquifer; the slots allow water to flow into the pipe to be pumped to the surface while preventing the surrounding sand and sediment from entering and clogging the system or damaging the pump.
Drainage and Stormwater Management
Slotted pipes are essential for controlling groundwater and preventing erosion or flooding. French drains use slotted pipe buried in gravel trenches to collect excess subsurface water and redirect it away from building foundations. Road and highway drainage installs slotted pipe beneath or alongside roads to prevent water pooling under the pavement, and agriculture uses subsurface tile drainage to lower the water table in soggy fields.
Oil and Gas Sand Control
In oil and gas production, slotted liners are used in well completion. They allow crude oil or gas to enter the wellbore while keeping formation sand out; in deep or high-pressure wells these are made of high-strength steel. API 5CT slotted tubing covers outside diameters from 60.3 to 114.3 mm, grades J55 through P110, R2 and R3 length ranges, and NU, EU, LTC, STC, BTC, or premium connections.
Landfill and Civil Applications
Slotted pipes collect leachate at the bottom of landfills so it can be treated, and are inserted vertically to capture methane gas produced by decomposing waste. In civil engineering, slotted pipes relieve hydrostatic pressure behind retaining walls and distribute or collect chemical solutions in heap-leaching mining.
Slot Selection Guidance
Slot width is customizable from 0.15 to 4.0 mm; for formation sand with a D50 of 0.2 mm, a 0.25 to 0.3 mm slot width balances sand control and flow capacity. The keystone slot, wider inside and narrower outside, is recommended for most sand control applications because of its self-cleaning performance, resistance to clogging, and longer service life.
Frequently Asked Questions
Q: What is the difference between slotted and unslotted pipe?
A: Slotted pipe has pre-cut openings for fluid passage and filtration; unslotted pipe is fully enclosed for fluid transmission only.
Q: What is slotted pipe used for in water wells?
A: As a well screen that lets water enter while keeping sand and sediment out.
Q: What slot width suits 0.2 mm formation sand?
A: 0.25 to 0.3 mm, balancing sand control and flow capacity.
Q: Which slot shape is better?
A: The keystone slot, wider inside and narrower outside, for self-cleaning and clogging resistance.
Q: What grades are available?
A: J55, K55, N80-Q, L80-1, C90, T95, and P110 per API 5CT.
Q: What connections are available?
A: NU, EU, LTC, STC, BTC, and premium gas-tight threads.
For API 5CT slotted tubing quotations with slot width and connection requirements, contact our sales team.
