Methods to evacuate various hydrocarbon fluids from underground storage containment locations using cross-compression technique

A system for evacuating a fluid mixture from an underground storage location comprising:a fluid mixture flow line configured to tie in to a drawdown section carrying a fluid mixture from the underground storage location;a separation vessel configured to receive the fluid mixture from the underground storage location via the fluid mixture flow line, wherein the fluid mixture contained in the underground storage location is pressurized at a pressure higher than a pressure of the fluid mixture contained within the separation vessel, and wherein the separation vessel is configured to separate the fluid mixture into a hydrocarbon fluid phase and a brine phase;a first pump configured to pump the hydrocarbon fluid phase from the separation vessel to a first dedicated containment volume via a hydrocarbon fluid phase flow line;

• anda second pump configured to pump the brine phase from the separation vessel to a second dedicated containment volume via a brine phase flow line.

A method to evacuate a fluid mixture from an underground storage location comprising:flowing the fluid mixture from the underground storage location towards a separation vessel,wherein the fluid mixture contains a hydrocarbon fluid phase and a brine phase,wherein the separation vessel is located next or above the ground level,wherein the fluid mixture contained in the underground storage location is pressurized at a pressure higher than the pressure of the fluid mixture contained within the separation vessel;separating the fluid mixture in the hydrocarbon fluid phase and the brine phase, inside the separation vessel;

• andsequentially pumping each phase of the fluid mixture, contained inside the separation vessel, towards dedicated and separated containment volumes, using at least two pumps,wherein a first pump is dedicated to pumping the hydrocarbon fluid phase from the separation vessel towards a dedicated containment volume,wherein a second pump is dedicated to pumping the brine phase from the separation vessel towards a dedicated containment volume, which is different than the dedicated containment volume for the hydrocarbon fluid phase.