Rig shaker screen cloth is a complex topic for oil drilling solids control also for industrial separation, and so on

Rig shaker screen

A standard rig shaker screen or fine shaker screen is vital to the solids control and should process 100% of the mud returning from the starting pit before allowing this mud to be processed by any of the down stream equipment you may utilize in your solids control system.

Some proprietary computer programs are available that reportedly allow predictions of screen sizes used on some shale shakers. Most of these computer programs have been verified with data taken from laboratory-prepared drilling fluid with limited property variation. Different drilling-fluid ingredients can reduce the capacity of a shaker system. For example, a drilling fluid containing starch is difficult to screen because starch, acting as a good filtration control additive, tends to plug small openings in screens. Drilling fluids with high gel strengths are also difficult to screen through fine screens. No charts will be presented here that purport to predict screen sizes that will handle certain flow rates. Screen selection for various shale shakers is primarily a trial-and-error evaluation. The best advice is to contact the manufacturer for recommendations for various geographical areas

Shaker screen cloth weave

Common rig shaker screen cloth weaves available in the petroleum drilling industry are the plain square weave, the plain rectangular weave, and the modified rectangular weave. These are simple over/under weaves in both directions, which can be made from the same or different wire diameters. By making the spacing between the wires the same in both directions, a square weave is created. By making the spacing in one direction longer than the spacing in the other direction, a rectangular weave is made.

Plain square and rectangular weaves are often referred to by the number of wires (the same as openings) in each direction per linear inch. This is the mesh count. Mesh is determined by starting at one wire center and counting the number of openings along the screen grid to another wire center 1 linear inch away. For example, an 8 mesh screen has 8 openings per inch in two directions at right angles to each other. When counting mesh, a magnifying glass scale designed for the purpose is helpful.

Use of a single number for screen description implies square mesh. For example, ‘‘20 mesh’’ is usually understood to describe a screen having 20 openings per inch in either direction along the screen grid. Oblong mesh screens are generally labeled with two numbers. A ‘‘60   20 mesh,’’ for example, is usually understood to have 60 openings per inch in one direction and 20 openings per inch in the perpendicular direction. Referring to a 60   20 mesh screen as an ‘‘oblong 80 mesh’’ is confusing and inaccurate.

Summarize on rig screen cloth

The actual separation that a rig shaker screen makes is largely determined by the size of the openings in the screen. The opening size of a square mesh screen is the distance between wires measured along the screen grid, expressed in either fractions of an inch or microns. Screen opening size is most often stated in microns. One inch equals 25,400 microns. Specifying the mesh count does not specify the opening size! This is because both the number of wires per inch and the size of the wires deter- mine the opening size.