Method and System for Co2 Enhanced Oil Recovery

An enhanced oil recovery system, comprising:

• a producer arranged to produce a well stream from a reservoir;
• a first gas/liquid separator arranged to separate the well stream into a liquid phase and a gas phase comprising both CO2 gas and hydrocarbon gas;
• a first cooler arranged to cool the gas phase;
• a first compressor arranged to compress the gas phase into a compressed stream;
• a mixer arranged to mix the compressed stream with an external source of CO2 to form an injection stream;
• and
• injection piping arranged to inject the injection stream into the reservoir.

A method used in Enhanced Oil Recovery (EOR) from an oil reservoir by CO2 flooding, comprising:

• producing a well stream from the reservoir;
• separating the well stream into a liquid phase and a gas phase with a gas/liquid separator;
• compressing the gas phase using a compressor;
• and
• recycling part of the compressed gas phase into the well stream upstream the gas/liquid separator or into the gas phase downstream the gas/liquid separator.