Definition - What does Accumulator mean?
An Accumulator is an energy-storing device that is used in hydraulic systems during drilling processes. It is also used in other applications such as dampening pressure fluctuations. The device stores energy by compressing a gas bladder which is charged a little bit (pre-charged) by the hydraulic fluid. The energy that is stored during the operation can be used independently without any power source during well pressure control applications.
Petropedia explains Accumulator
Oil and gas accumulators store incompressible fluid under high pressure via external source such as using spring, liquid or a gas or a piston. These accumulators are hydro-pneumatic devices and can be used in the blowout preventers, drilling rigs and mud pumps. Their main purpose is to handle the pressure fluctuations, noise reductions, pulsation damping and leakage compensation. The material used for to manufacture accumulators depends on the applications in which these accumulators are to be used, i.e., based on different pressure ranges.
Well pressure-control systems typically incorporate sufficient accumulator capacity to enable the blowout preventer to be operated with all other power shut down.