This invention relates to a fluid accumulator comprising a wall (2) encompassing a reservoir (1) for receiving the fluid, part of the wall being elastically deformable. The wall (2) of the fluid accumulator comprises a first wall portion (2A) that is made of a first elastically deformable composite, with fibrous reinforcement material applied in a first density, and a second wall portion (2B) that is made of a second composite with fibrous reinforcement material applied in a second density and an elastic deformability that is the same as or different from the elastic deformability of the first wall portion, the density of the fibrous reinfrocement material in the first and second wall portion (2A, 2B) being different.