WATCH · Watch — trend and planMud system →Cost of fault ≈ $150k+ / incident
Why it matters
High dilution is the symptom that pays for every upstream fault. Rising LGS thickens the mud, slows ROP, raises ECD and drives barite-sag risk — and the only short-term lever, dilution, is the most expensive barrel on the rig.
Likely causes
Upstream removal failing — shaker bypass, low cone head or centrifuge offline. The real root, most often.
Screens too coarse / bypass gates open — fines never removed at stage one.
Centrifuge under-run — not enough hours to strip colloidal fines.
Excess dilution masking the problem — building volume instead of removing solids.
High near-size / colloidal load the equipment can’t catch.
No mass-balance discipline — nobody tracking solids in vs solids out.
How to diagnose it
Run the mass balance: solids generated (bit size + footage) − solids discarded = solids in active. If it doesn’t close, solids are accumulating.
Trace the train upstream: shaker pool, cone apex (feed head), centrifuge hours.
Check bypass gates — an open bypass is invisible from the cabin.
Trend LGS / PV against dilution volume.
The fix — step by step
Fix removal at the earliest stage first: shaker screen + managed pool, then cone feed head, then centrifuge duty/hours.
Close bypass gates; confirm dirty-to-clean flow with no open equalisers.
Increase centrifuge run-time on colloidal load before reaching for dilution.
Treat dilution as the last lever, not the first.
Confirm it's fixed
✓ Verify: LGS trending back into band with a falling dilution rate, and a mass balance that closes. The proof isn’t one good shift — it’s dilution volume per foot dropping over the section.
Field note. Dilution is where every other failure shows up as money. Before you build more mud, walk the train: nine times out of ten the “mud problem” is a shaker screen, a cone running at low head, or a centrifuge that’s been off all tour.