Brazil’s Petrobras has ordered six two-stage screw compressors from MAN Diesel & Turbo for managing gas at a subsalt field 190 miles (300 km) off São Paulo in the Santos Basin.

Each package will compress oil-associated gas in two stages, using a combination of Skuel and CP oil-free screw compressors, each of which represents one compression stage. Skuel compressors with horizontally-split casings draw in high volumetric flows at comparatively low discharge pressures. CP compressors with vertically split casings can generate discharge pressures that are three times higher but process lower volumetric flows.

MAN said using both types combines their respective advantages. The Skuel stage pre-compresses the process gas, but, with increasing density, its volumetric flow is reduced. The CP stage is then able to additionally increase the pressure.

In a further step of the process, turbocompressors will bring the gas to a discharge pressure of more than 7250 psi (500 bar) for reinjection, which prevents gas flaring and CO₂ emissions, the company said.