This paper discusses two novel findings. Firstly, 4D microgravity data are used to estimate density changes for each reservoir layer using deconvolution technique supported by reservoir physical properties and volume of fluid injection and production. Secondly, the density change values resulted from the deconvolution technique are applied for 3D simulation of a reservoir fluid flow. In this study, the 3D numerical approximation of two-phase incompressible and immiscible problems derived from fluid flow formulation in conjunction with 4D microgravity formulation has been developed. The implication of gravity effect in fluid flow has been quantified by the 4D microgravity method. In addition, a 3D gravity forward modeling program has been created to test the value of density changes resulted from the deconvolution and simulation techniques. For case study, 4D microgravity measurement data at âSSâ oil Field, Central Sumatra, Indonesia, has been used. âSSâ oilfield is a multilayer sandstone reservoir and the depth of reservoir target is approximately 700 m. The result has shown that application of the 4D microgravity data in fluid flows monitoring and simulating gives a better interpretation of reservoir fluid flow dynamics.