A solids-control audit is a systematic inspection of the entire surface separation train — equipment condition, settings, plumbing and operating data — against the standard it is supposed to deliver. Every item corresponds to a failure mode with a cost, and the audit's value is finding those failures before they run for a section.
Shale shakers
- Screen condition: walk each panel; holes, worn spots, lifted edges.
- Fluid pool (beach): pool running off the end = overloaded. Dry deck = could go finer.
- Bypass gates: confirm every gate position — an open bypass is invisible from the cabin.
Hydrocyclones
- Feed head: h = 19.2 × p ÷ ρ. Below ~75 ft, the cones are not cutting.
- Apex spray: umbrella = healthy. Rope = overloaded or low head. Dry plugging = cut too aggressive.
Decanting centrifuge
- Bowl speed vs duty: confirm settings match one duty — not a compromise.
- Conveyor torque: rising torque = cake accumulating. Catch it before the bowl packs.
- Flushing log: confirm flush-at-shutdown is happening every shift.
Pit system
- Flow direction: dirty-to-clean with no open equalising valve.
- Agitators: all running; a still surface means solids on the floor.
The mass balance — the audit's bottom line
solids generated (bit size + footage) − solids discarded = solids in active
If the numbers don't close, solids are accumulating and dilution will follow. This single calculation often surfaces what the walk-around missed.
Key takeaways
Walk the train in order, write down what you see, calculate feed head, run the mass balance. The cost of an audit is a few hours; the cost of the faults it finds is measured in dilution barrels and rig time.