Abstract: The application of top gas injection-assisted gravity drainage technology in domestic oilfields is still in the exploratory stage. Based on the comprehensive consideration of the formation's geological parameters, development parameters, and other factors, preliminary qualitative and quantitative screening conditions for identifying reservoirs suitable for gas-assisted gravity drainage were established. A bottom water sandstone oil reservoir in the western part of China, where top gas injection-assisted gravity drainage technology was implemented for the first time first in China, was used as an example. Combined with the reservoir engineering method, numerical simulation method, field dynamics, and monitoring results, studies on the key points of gas-assisted gravity drainage reservoirs, estimation of gas injection scale, optimization of well opening timing, and stability of the gas-liquid interface were carried out. Key technologies of gas-assisted gravity drainage technology were discussed, including injection optimization control technology, production well switch and control technology, injection and production optimization perforation technology, dynamic tracking, and adjustment technology. Finally, for the control of gas-liquid interface stability, the technology policy was proposed that recommended focusing on both injection and production, zoning to control pressure and limit production, and tracking interface adjustment.

Key words: gravity drainage, screening conditions, gas injection scale, gas-liquid interface stability