A sight glass shows you the oil level and, on a three-phase vessel, the oil-water interface. However, that reading is accurate only if the glass is clean and opened correctly. Additionally, a level controller acts on what it senses through a displacer, a mechanical link that can fail quietly. If it does, the controller doesn't stop and keeps acting on whatever position it's stuck in, confidently managing a level that no longer reflects what's actually in the vessel. A three-phase separator runs two of these, one for oil and one for water, and either can fail the same way. The training walks through how that mechanical chain works and where it breaks.

Three devices generally protect the vessel and the process, each guarding a different failure: the pressure gauge, a high level kill, a low level kill, and the relief valve, the vessel's last line of defense at its maximum allowable working pressure. The training dives into what each one is watching for and when it's supposed to act.

In the field, a failed accessory shows up as one of two patterns. Gas out the dump line usually means the displacer has fallen off, and liquid out the gas line means the level rose too high before the high level kill caught it. The training covers the reasons these failures can happen, how to tell which one you're looking at, and strategies to fix them.

On a multi-well pad, a sales meter reads only the combined total for every well on the pad, and can't tell you what any single well is actually producing. A well test isolates one well into a dedicated test separator so per-well numbers an be measured and used for targeting work needs, production allocation, royalties, and decline tracking.

The valve lineup takes center stage during a well test, as getting the sequence wrong can deadhead the well, shut in against itself with nowhere for pressure to go. Accessories still play a major role as gauges or kills catch when a device has failed. Nothing catches a valve lineup done out of sequence except the person doing it, so training what that correct sequence looks like is critical.