Upstream · Production
Primary treatment
What comes out of the well is not crude: it is a mix of oil, water, gas and sand. Primary treatment makes it shippable — separated, dry, stabilised, desalted — before it enters the pipe. It is the step websites forget and the pipeline never forgives.
What the well delivers, and what the pipe demands
At the wellhead the effluent arrives hot, pressurised, laden with formation water, dissolved gas and solids. The export pipeline accepts only crude that is stabilised (controlled vapour pressure), dehydrated (under 0.5% water and sediment) and desalted (chlorides corrode steel and poison the refiner’s catalysts). Between the two sits a chain of unit operations the industry calls primary treatment, run in a central processing facility — the CPF.
The six operations, in flow order
- Manifold and gathering — lines from several wells converge; each well is test-metered before blending.
- Three-phase separation — in successive high- then low-pressure separators, gas breaks out, free water settles, oil floats. On heavy crude separation is slow: heat and residence time are added.
- Heating and dehydration — the oil-water emulsion is broken by heat, demulsifiers and, where needed, an electrostatic field. This is the most sensitive stage on Doba crudes, whose naphthenic acids stabilise emulsions.
- Desalting — fresh water is injected then removed to carry away dissolved salts.
- Stabilisation — the lightest fractions are flashed off so the crude does not “boil” in tanks or in the pipe.
- Fiscal metering and export — treated crude is gauged, sampled, then pushed to buffer storage and the pipeline. The metered figure is the number that binds producer, State and carrier.
In Chad: a heavy, acidic crude that rewards method
Doba crudes are heavy (21–24° API), viscous and rich in naphthenic acids. Three consequences for primary treatment: stubborn emulsions that need heat and chemistry, acid corrosion that dictates steels and inhibitors, and abundant produced water — often several barrels of water per barrel of oil on a mature field — to be treated and reinjected rather than discharged. Associated gas, small in volume but real, fuels the site’s heaters and engines instead of being flared: the “zero routine flaring” rule we adopt from design.
What we put in place
Skid-mounted separators, heaters and desalter, sized per field and movable from one marginal block to the next — the same logic as our mini-refinery.
Demulsifiers and inhibitors formulated with our chemicals pole; Chadian natron as neutralising alkali, lab-tested before any deployment.
Treatment, reinjection for pressure maintenance, and valorisation where possible — the Water-to-Value™ programme.
Certified fiscal metrology, corrosion monitoring, inspection of pressure vessels: primary treatment is also an HSE station.
Benchmarks
| Parameter | Export target | Why |
|---|---|---|
| Water & sediment (BS&W) | ≤ 0.5% | pipe corrosion, metering penalties |
| Salt | ≤ 10–20 mg/l (PTB) | corrosion, catalyst poisoning |
| Vapour pressure (RVP) | per carrier specification | storage and transport safety |
| Routine flaring | zero | GreenTech commitment, value of gas |
Industry orders of magnitude; contractual specifications are set with the carrier and the refiner.