Oil production in unconsolidated reservoirs such as sandstone can be really challenging because of solids coming from the formation. In order to solve problems caused by produced solids, frac-packing is one of the methods used. It aims to maintain or increase production and control produced solids. This research focuses on the hydraulic fracturing part of that method. A numerical model is created using CMG-2015 with data from a given field to analyze the effects of some factors on oil production. Two cases are considered in this research, the first one is a one-layer case and the second one is a two layers case. Water is injected into the reservoirs in both cases. The results reveal that formation damage by its degree (Ks/K) and size can significantly decrease oil production and fracturing treatment can help recover the oil production to almost the initial value. After bypassing the damaged area, keeping increasing fracture half-length and conductivity is not important because there is no significant effect on the production. The results also show that for double layers case, the best way to increase oil production is to fracture the low permeability layer and maintain or leave the formation damage that will naturally happen.