SUPPORTING · GAS REMOVAL

Vacuum degasser

Well-control hardware that lives in the SC area

The degasser is the one machine most often misunderstood as “a well-control tool that lives near solids control.” It is both. Entrained gas in the mud is a well-control concern — it lightens the column — but it is also the fastest way to cripple the whole cyclone train, because a centrifugal pump cannot build head on gas-cut mud and a cone cannot hold its air core on aerated feed.

What it does

Strip entrained formation gas out of the returning mud, restoring its true weight, before the fluid reaches the cyclone feed pump — protecting both the hydrostatic barrier and the cones' feed head.

How it works

A vacuum degasser pulls a vacuum on a sealed vessel and spreads the mud into a thin film over internal plates, so the reduced pressure draws entrained gas out of the large exposed surface area and vents it off. (An atmospheric centrifugal degasser does the same job at atmospheric pressure, spinning the mud against the vessel wall in a thin film.) Either way the unit sits after the shakers and before the cyclone feed pump.

Key components

Sealed vessel & internal platesThe mud is spread thin over the plates so gas can break out under vacuum.

Vacuum pumpDevelops and holds the vacuum that draws the gas out; the heart of the unit.

Vent lineCarries the separated gas safely away; plugging or liquid carry-over defeats the unit.

Float / level controlHolds the correct mud level — too high floods, too low loses the seal.

Seals & gasketsHold the vacuum; an air leak here and the vessel can't develop vacuum.

Operating parameters

Parameter	Range	Notes
Position	after shakers, before cyclone feed pump	A pump can't build head on gas-cut mud
Type	vacuum / atmospheric centrifugal	Vacuum vessel, or spinning rotor at atmosphere
Confirm each tour	vacuum develops on start-up	A dead gauge = mechanical fault

Health indicators — what good looks like

Vacuum developing on start-up and holding.
Flowline-to-suction mud-weight gap closing on gas-cut returns.
Vent line clear, no liquid carry-over.
Pumps running smooth — no gas-induced cavitation.

Common problems & how to fix them

The failures this machine throws, each with a full field fix:

Poor gas removal

Gas-cut mud passing untreated — often a valve line-up error.

Troubleshoot →

Low / no vacuum

Mechanical — pump, belt, seal or vent line.

Troubleshoot →

Field tips

Prove the line-up and the vacuum every tour — a 60-second check; the line-up is the fault more often than the machine.
It's well-control hardware that happens to live in the SC area — prove it works before you need it.
A dead vacuum gauge on start-up is a mechanical job (pump, belt, seal, vent), not a process one.

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