3.Three phase test separators per ten wells

### *4.1.5 Separation process*

Surface facilities in CO2-EOR requires recovery of CO2 and reinjecting it back to the well, with which CO2 release to the atmosphere can be minimized as well as purchasing cost of additional CO2 can be reduced. Typical surface facilities for CO2- EOR are gas separation. Water treatment of CO2 compression and injection and also dehydration can be seen in **Figure 7**.

Dehydration column removes the moisture content of the gas stream by using the contact with lean glycol in the upper part of the 14 tray column and the gas must be cooled first by the air cooler. Rich glycol is extracted from the bottom of the

**Figure 6.** *Modifications on CO2 production well head [5].*

**Figure 7.** *Typical surface facilities for CO2-EOR [21].*

column and directed to the regeneration system, and dry gas passes through from the top to the compressor package.

A slug catcher is to catch any water as water will be continuously dropping, which may unload in slugs. Then, three-stage reciprocating compressor is used to increase the pressure of CO2 from 700 kPa(g) to approximately 10,000 kPa(g). At the first stage reciprocating compressor at 3000 kPa the CO2 is dehydrated. Afterwards, CO2 liquid is trucked to the site to supplement injection requirement and stored in refrigerated bullet. Then, the cryogenic triplex pumps are used to pump the CO2 liquid to injection pressure. After that, the liquid and compressed gaseous CO2 are commingled in a mixer [40]. A minimum well head temperature must be maintained so as not to freeze the inhibited water in the well annulus. Should the injection compressor be shut in, liquid CO2 is warmed by a trim heater.
