Abstract: With the discovery of a mass of natural gas resources and the continuous improvement of EOR technology by natural gas injection process, the heavy oil reservoir developed by natural gas injection process has become significant technical means for EOR. In view of the geology and exploitation of deep heavy oil reservoir in an oil field, based on the lab experiment and phase behavior simulation, this paper builds up the numerical simulation model for such a reservoir, and optimizes the parameters of the EOR program by cyclic natural gas injection process using the compositional model after history match and modification. According to the parameter optimization program of deep heavy oil reservoir by cyclic natural gas injection process, good effects of incremental oil production and reducing water cut have been gained.

Key words: deep zone, heavy oil, natural gas, huff and puff, numerical simulation, optimized design