Abstract: Lukeqing heavy oil reservoir is characterized by deep, thick and poor physical properties, difficult to exploit it using existing techniques for heavy oil thermal recovery. This paper presents the process of natural gas stimulation (huff and puff) to do it, which depends on the experiment of physical modeling. It is recognized that the key mechanism of this process is that there exists pseudo- bubble point after gas injection, forming foaming oil for disperse visbreaking besides conventional dissolution viscosity break. In the process of natural gas huff and puff, from the bottom hole of gas injection well to the distal formation, the formation zone will be divided into oversaturation section, saturation section and undersaturation one. Based on these, the field test is made and good effect is gained.

Key words: Tuha basin, Lukeqing field, heavy oil, natural gas huff and puff, stimulation, foaming crude