ESP
ESP is an abbreviation of 'Electrical Submersible Pump'. When a reservoir does not have enough energy to flow naturally, artificial lifting techniques are used to flow the formation fluid to the surface. The most adopted artificial lift method is ESP. An Electrical Submersible Pump houses multiple centrifugal pump stages mounted in series coupled to a submersible electrical motor. This assembly is lowered in the well and is connected to controls at the surface. Multiple stages of ESP connected in a series use impeller and diffuser arrangements to increase the flow pressure. The ESP stages are designed so that after the last stage, fluid attains enough pressure to flow to the surface naturally.