Usually, if solids are being removed with shale shakers, a mud cleaner will probably be beneficial. Solids removed by mud cleaners will cover a wide range of quantities depending on formations drilled, borehole stability, dispersion of solids as they move up the borehole, type of drill bit, type of drilling fluid, and other variables.
Arranging And Operating Mud Cleaner
The weighted mud flows to the inlet head section of the desander and/or desilter entering the hydrocyclones for separation of particles. Mud leaving the underflow is further screened with fine mesh to separate larger particles allowing only barite size particles to pass through the screen returning and recovering then the clean mud.
Hydrocyclones discharge
Most hydrocyclones are of a balanced design. A properly adjusted,
balanced hydrocyclone has a spray discharge at the underflow outlet and exhibits a central air suction core. Many balanced hydrocyclones can be adjusted so that when water is fed under pressure, nothing discharges
at the apex. Conversely, when coarse solids are added to the feed slurry,
wet solids are discharged at the apex. Even with this adjustment, there
still should be a large opening in the bottom of the cyclone. This will
confirm that the cyclone is hydraulically balanced and discharges at the
bottom (apex) only when solids, which the cyclone can separate, are in
the feed slurry (drilling fluid).
Solids Control Equipment and Gas Cutting
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Shale Shakers And Gas Cutting
Shale shaker screening is dependent on a constant flow of drilling fluid
with cuttings. The fluid must pass through the screen, and the cuttings
must either pass through or be rejected by the screen. Gas cutting in the
drilling mud can have up to three different effects that upset the screening
process.
1. Gas heading can cause volume surges in the mud flow that exceed
the ability of the screen to handle fluid flow. This is usually from gas,
intermixed in the mud, rapidly expanding at the surface and pushing
large surges of drilling fluid out the flowline. Gas busters and gas
separators are the solutions to this problem.