Johnson type stainless steel gravel pre-pack well screens have two types.
One type consists of two layers wedge wire screens and the middle filter.
The other type consist of perforated base pipe or slotted API casing pipe and outer screen jacket.
The base pipe can be stainless steel or carbon steel API 5CT casing. Having the API casing inside a wire wrap screen jacket is supporting the screen and enhance the capabilities and high tensile strength Loads. Base pipe can be made from API pipe seamless casing spiral or stainless steel casing. Opening area for the base pipe is up to 15% and for the jacket is up to 30%. Johnson type jacket slot size is between 0.15mm to 3mm.
Gravel Prepacked Well Screens
Johnson Type Gravel Prapacked Well Screens