Since the 1960s, because of the relevance to the oil industry, the numerical simulation of hydrocarbon reservoirs has received special attention and has been the subject of extensive studies. The main goal of computational modeling and the use of numerical methods for reservoir simulation is to allow better placement and control of wells, so that there is a optimized oil recovery. In this work, production of hydraulically fractured horizontal wells in light tight oil reservoirs will be studied. In this case, fractures do not form a continuous conductive network and can communicate hydraulically with only the horizontal producer well. In order to do that, a simulator for three-dimensional oil flow in reservoirs, suitable for applications in the field scale, already developed, using the Cartesian coordinate system and a finite difference approach, will be applied for the study of hydraulically fractured horizontal wells. Originally, this simulator and its grid refinement tools had been used only on the simulation of naturally fractured reservoirs. The nonlinear partial differential equation resulting from physical-mathematical modeling, written in terms of pressure, will be solved numerically after discretization and linearization using the Preconditioned Conjugate Gradient method. The main objective is to study the combined effects of hydraulic fractures and horizontal well on the wellbore pressure profile, considering different light tight oil production scenarios. Numerical simulations displayed the influence of important parameters on the well-reservoir system in study, such as fracture permeability and matrix porosity. A study of this type is relevant on the discussion of reservoir production strategies, helping on the decisions about a hydraulic fracturing operation in order to obtain economic viability for the hydrocarbons recovery project.