By Othman Soliman — Solids Control & Drilling-Waste specialist, 26+ yrs (GCC & MENA). Last reviewed .
ACT · Act now — correcting soonShale shaker →Cost of fault ≈ $60k+ / incident
Why it matters
Bypass is invisible from the cabin and quietly defeats the first removal stage. It shows up downstream as rising LGS, loaded cones and a centrifuge that can't keep up — chased everywhere except the one open path at the shaker.
Likely causes
Failed / missing screen gaskets or seals — mud tracks around the panel.
Holed or torn panels (see screen failure).
Worn deck rubbers leaving gaps at the panel edge.
Bypass gate / equaliser left open — invisible from the cabin.
Incorrect panel seating after a change-out.
How to diagnose it
Inspect gaskets, seals and panel seating for tracking paths.
Backlight panels for holes (screen failure).
Physically check every bypass gate / equaliser — open or shut.
Trend LGS / sand against shaker condition.
Confirm deck rubbers are sound at the panel edges.
The fix — step by step
Close and confirm all bypass gates and equalisers.
Replace failed gaskets / seals and re-seat panels correctly.
Replace holed panels with the correct API screen.
Renew worn deck rubbers so panels seal at the edge.
Standardise post-change-out checks to confirm a full seal.
Confirm it's fixed
✓ Verify: All flow confirmed going over the screen — bypass gates shut, gaskets sound — and LGS trending down.
Field note. An open bypass is invisible from the cabin — and it is the first thing I check when LGS is climbing and the shaker ‘looks fine.’ Nine times out of ten the mud problem downstream is a path around the screen, not a fault in any machine.
The 10 Solids-Control Numbers Every Engineer Must Track — what to measure, the formula, the field target and the red flag. Grounded in API RP 13B-1, RP 13C, EPA 40 CFR 435 & OSPAR.
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