No vacuum means no gas stripping, so gas-cut mud passes through untreated — the same well-control and pump-cavitation risks as poor gas removal, traced to a mechanical cause. Cost basis: the headline figure is an illustrative exposure, not a measured incident cost or a validated typical value. No incident-specific inputs are provided for it. Estimate your case as incremental fluid loss or dilution (bbl/day × days × $/bbl), plus incremental waste treatment/disposal and documented NPT (hours × $/hour), avoiding double counting. Record the baseline, duration, fluid cost and verified change before claiming savings.
Likely causes
Vacuum pump fault — worn, fouled, or not turning.
Drive belt slipping or broken; motor fault.
Failed seals / gaskets letting air in.
Vent line plugged or liquid carry-over flooding the vessel.
Wrong mud level breaking the seal.
Heavy carry-over loading the vacuum system.
How to diagnose it
Confirm the gauge reading on start-up against design vacuum.
Check pump, belt and motor operation.
Inspect seals / gaskets for air ingress.
Check the vent line for plugging or carry-over.
Verify mud level holds the seal.
The fix — step by step
Service or replace the vacuum pump; renew the belt; fix the motor.
Replace failed seals / gaskets so the vessel holds vacuum.
Clear the vent line and stop liquid carry-over.
Set the correct mud level to maintain the seal.
Confirm design vacuum is restored before relying on the unit.
Confirm it's fixed
✓ Verify: Design vacuum developing on start-up and holding; vent line clear and seals tight.
Field note. Low vacuum and ‘not pulling gas' are usually the same fault from two ends. Always confirm vacuum develops on start-up — if the gauge is dead, you have a mechanical job (pump, belt, seal, vent), not a process one.
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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