A method for processing a flowback composition stream from a well head includes controlling a first flow rate of the flow back composition stream to a second flow rate by regulating the flowback composition stream from a first pressure to a second pressure. The method also includes separating the flowback composition stream into a first gas stream and a condensed stream. The method includes discharging the condensed stream to a degasser and degassing a carbon dioxide rich gas from the condensed stream. The method also includes mixing the carbon dioxide rich gas stream with the first gas stream to produce a second gas stream. The method includes controlling a third flow rate of the second gas stream by regulating a third pressure of the second gas stream to a fourth pressure that is different than the third pressure.